Journal of Advances in Microbiology

5(2): 1-21, 2017; Article no.JAMB.35591 ISSN: 2456-7116

Archaea Domain as Biocatalyst in Environmental Biotechnology and Industrial Applications: A Review

Mohd Asyraf Kassim1*, Noor Haza Fazlin Hashim2,3 and Nur Athirah Yusof4

1Bioprocess Technology Division, School of Industrial Technology, Universiti Sains Malaysia (USM), Malaysia. 2School of Biosciences and Biotechnology, Faculty of Sciences, Universiti Kebangsaan Malaysia (UKM), Malaysia. 3Water Quality Laboratory, National Hydraulic Research Institute Malaysia (NAHRIM), Seri Kembangan, Malaysia. 4Biotechnology Research Institute, Universiti Malaysia Sabah (UMS), Malaysia.

Authors’ contributions

This work was carried out in collaboration between all authors. Author MAK manage the outline and literature search and wrote the first draft of the manuscript. Authors NHFH and NAY helped in the writing certain part of the manuscript such as introduction and revised the manuscript. All authors read and approved the final manuscript.

Article Information

DOI: 10.9734/JAMB/2017/35591 Editor(s): (1) P. Rama Bhat, PG Biotechnology, Alva’s College, Karnataka, India. Reviewers: (1) Eliton da Silva Vasconcelos, Federal University of São Carlos – UFSCar, Brazil. (2) Selma Gomes Ferreira Leite, Universidade Federal do Rio de Janeiro, Brasil. Complete Peer review History: http://www.sciencedomain.org/review-history/20731

Received 20th July 2017 Accepted 21st August 2017 Review Article Published 30th August 2017

ABSTRACT

Achaea constitute a considerable fraction of the prokaryotes which colonize marine and terrestrial ecosystem especially in the extreme environments. These microorganisms play crucial roles and contribute significant impacts on global energy cycles. In fact, the extremophilic characteristics acquired by many archaeans display unusual properties of adaptations to extreme conditions which make them a potentially valuable resource in exploring new biotechnological processes and a wide range of industrial applications. In this review, the role of domain as biocatalysts in environmental biotechnology and industrial applications were summarized and discussed. This review has been categories into three main sections, (a) archaeal characteristics and their extremozymes (b) environmental biotechnology that covers on , hydrocarbon biodegradation and biomining (c) industrial applications, which discusses on the production of polyhydroxyalkanoates (PHA), biosurfactant, and antibiotic produced by archaea domain.

______

*Corresponding author: E-mail: [email protected], [email protected];

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

Keywords: Archaea; aromatic; ; extremozyme; halocin; polyhydroxylalkanoate (PHA).

1. INTRODUCTION shapes, ranging from spherical, spiral, oblong, rectangular to rod. One of the distinguishing Archaea are prokaryotic microorganisms that can features of archaea is the structure of their be found in the extreme environments. Due to membrane glycolipids; where archaea do not their capability to live under extreme conditions, contain murein at their cell wall. Archaea exhibit the exploration on the potential of archaea as unique features of cell surface organelles that biocatalysts for industrial applications has are not present in bacteria such as flagella, hami, become the subject of intensive research, aiming cannulaeand pili [1]. on the cell structures, enzyme characterizations and its adaptability under extreme conditions. Year 1977 marked a history when Carl Woese, a These exclusive properties make them as a microbiologist discovered two distinct groups of valuable resource with great potential organisms that were not related to one another applications in a wide range of new technologies. than they were to eukaryotes [2]. Later, a new classification was proposed based on Moreover, the study on archaeal enzymes that comparisons of gene sequences of the small are able to maintain their activity under extreme ribosomal subunit (SSU), which was accepted conditions such as high temperature, salinity, pH until now; three domains of life consist of and pressure has also gain great interest among Eukarya, Bacteria and Archaea [3]. After the researchers. The discovery of extremophilic discovery by Woese, molecular biology archaea and their enzymes has lead to techniques have been the preferred choice to significant effects conspicuously on biocatalysis distinguish between archaea and bacteria. activities. In addition, extremozymes produced by Indeed, the organization and information archaea are widely used in the synthesis of processing system in archaea point to a closer pharmaceutical products, antibodies, cosmetics, relationship to eukaryotes rather than bacteria. dietary supplements, enzymatic preparations, Apart from that, the structures of ribosomes and bioremediation, renewable energy, as well as all chromatin, presence of histones and sequence kinds of chemical compounds production. The similarity contribute to the classification of application of extremozymes from archaeal cells archaea [4,5]. In contrast, the metabolic has allow great improvements in multiple industry pathways of archaea show similarity to sectors and help to reduce the quantity of waste prokaryotic rather than eukaryotic counterparts production, energy usage and material [6]. Table 1 shows the comparison of consumption. Thus, archaeal applications harbor characteristics between bacteria and archaea. promise for creating cheaper technology, cost- effective sustainable energy sources and 3. BIOCATALYST environmentally friendly. The trend to an increasing number of researches The main hallmarks of this review are to discuss on genome data of extremophilic microorganisms and provide a comprehensive review on the worldwide has able to discover hundreds of future prospects of achaea as biocatalysts in enzymes with great potential in white environmental biotechnology and other industrial biotechnology. Currently, extremozymes are applications. In this review, the emphasis highly in demand in industries as they are able to encompasses on the type of extremozymes that withstand harsh processes for a long period of are produced by different group of achaea, time. Overall at present, microbial enzymes are enzymes and metabolites production and their currently on demand in various industries as they potential industrial applications. This review contribute immense advantages such as would be beneficial to scientists and researchers reducing the risk of contamination, improving the in understanding the potential of achaea as tools transfer rates, lowering viscosity and increasing for various value-added products and the solubility of substrates. Majority of the revolutionize the current industrial applications. industrial enzymes have been derived from bacteria and fungi. Nowadays, archaeal enzymes 2. ARCHAEA are in the limelight of intensive investigations due to their nature that grow optimally at extreme In general, Archaea have similar characteristics conditions. In terms of definition, extremozymes as bacteria in terms of shape, size and are enzymes that are able to withstand appearance. Archaeal cells can take all types of harsh and extreme conditions in industrial

2

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

Table 1. Comparison of the distinctive characteristics of Archaea and Bacteria

Archaea Bacteria Ribosome Present Present Cell wall Pseudopeptidoglycan Peptidoglycan/Lipoposacchari de Habitat Extreme environment: hot spring, Soil, water, animal, plant and salt lake, ruminant etc. Growth Asexually by the process of binary  Asexually by the fission, budding and fragmentation binary fission, budding and fragmentation  Ability to form spore Genomic organization  Topoisomerase I I/III  Recombinase RadA RecA  DNA ligase NAD dependant ATP dependant  Replicative HelicaseA DnaB helicase  DNA polymerase Family B polymerase DNA E polymerase (PolIII)  Histones Yes No  Introns Some present Rare/none  Protein synthesis Methionine as start codon Formylmethionine as start codon Example Family Family Enterobactericeae Euryarchaeota (Aciduliprofundum (Escherichia coli) and boonei) and Crenarchaeota Streptococaceae ( solfataricus) (Streptococcus pneumoniae) processes [7]. Perhaps, the high demands of the temperature such as increased hydrophobicity biotech industries for tailor-made novel and surface charge, higher hydrogen bonds, biocatalysts, and the rapid development of new shorter loops structure, reduction in thermolabile techniques such as genomics, proteomics and amino acid, and lowered in surface area to metabolomics are the main factors contributing volume ratio [9]. Owing to that, thermophilic the enhancement of the development of novel enzymes are currently on demand in vast extremozymes. Here, this review will focus on industries which require superior biocatalysts that enzymes that are derived from extremophilic are capable to work at high temperatures. archaea and their relevance for industrial Moreover, reactions at high temperatures reduce applications. the probability of undesired by-products and microbial contamination. In addition, thermophilic 3.1 Thermophilic Extremozymes archaea also show high resistance under high pressure and presence of chemical denaturants can be further categorized either such as solvent and detergents [10]. as thermophiles or hyperthermophiles. Hyperthermophiles can grow optimally up to Glycoside hydrolases are large group of 115°C, whereas thermophiles grow best between enzymes involve in carbohydrate hydrolysis. 50 and 70°C. Majority of thermophiles/ Enzymes in this group are greatly in demand hyperthermophiles are identified to date belong especially those that are able to perform at high to the archaeal domain mainly from temperatures. Glucose production from starch for Crenarchaeota, Euryarchaeota, Korarchaeota instance, involves two-step processes where and Nanoarchaeota [8]. Most common habitats both are carried out at high temperature of (60- where archaea are naturally found are in the 105°C) and acidic pH of (4.5–6.0) [11]. The volcanic areas, geothermal systems and hot usage of thermostable amylolytic enzymes springs. To date, protein structural studies on (α-amylases, α-glucosidases, α-pullulanases) thermophilic enzymes show several factors provides advantages as novel energy which contribute to the enzymes stability at high alternatives, cost saving, as well as

3

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

environmentally friendly process. Currently, was isolated from thermophilic bacteria, hydrolytic enzymes from Bacillus Thermusaquaticus [19]. Recently, polymerases stearothermophilus and B. licheniformis are from archaeal have been developed since these currently being used in the industry. Interestingly, polymerases show prominent advantages such several studies have reported higher activities of as stringent proofreading ability and five to thermostable hydrolases enzymes from archaea tenfold lower of error rates compared to compared to bacterial enzymes. On the other Taqpolymerase. Several DNA polymerases from hand, hyperthermophilic amylases are also archaea are already isolated and exhibited high reported from archaea of the genera Sulfolobus, commercial values such as from Thermococcus Thermophilum, Desulfurococcus and celericrescens (TceI) [20], Thermococcus Staphylothermus, which are recorded to be fumicolans (Tfu) [21], Thermococcus zilligii (Tzi) active at a broad range of temperatures ranging [22], Pyrococcusabyssi (IsisTM) [23]. from 40–100°C [12]. In addition, another study on thermostable α-amylase from Pyrococcus 3.2 Psychrophilic Extremozymes furiosus reported that the enzyme has a half life activity at 120°C after autoclaving for 2 hours Psychrophiles are defined as microorganisms and fascinatingly still exhibit residual activity at that are able to proliferate at 0–10°C, 140°C [13]. In another study, thermophilic metabolically active at subzero temperatures and pullulanases which usually belong to the type II also able to survive as low as −45°C [24]. class acquired enzymes that are able to Psychrophiles can be found either in hydrolyze both α-1,4- and α -1,6-glycosidic permanently cold environments such as bonds in branched polymers [11]. A heat-active permafrost, sea ice, polar, glacier or artificially pullulanase with an optimum temperature of cold environment such as the refrigerator. In 100°C has been discovered in Thermococcus order to adapt, psychrophiles produce enzymes kodakarensis KOD1 [14]. α-glucosidases are that are able to work optimally at cold involved in the final step of starch degradation, temperatures. Generally, cold adapted enzymes hydrolyzing terminal glucose residues. have higher structural flexibility and catalytically Thermophilic archaeal P. furiosus α-glucosidase effective at cold. Several features of cold has been characterized extensively where it adapted proteins have been reported to show works optimally at the range of temperatures unique characteristics compared to their between 105–115°C [15]. mesophilic and thermophilic counterparts. These include fewer disulfide bonds and salt bridges, Similarly, xylanases have been widely studied more solvent interactions, lower number of due to their ability to degrade hemicelluloses; the hydrogen bonds at domain interfaces, lower core most abundant natural resources. This type of hydrophobicity, and longer loops structure [25]. enzymes advocates attractive value to the paper bleaching industry; as an alternative to current Studies on psychrophilic archaea mainly focus chemical treatment; thus promoting an on methanogens as they play important roles in environmentally friendly industry [16]. However anoxic permanently cold environment like lake bleaching process performs optimally only at sediments, deep sea and permafrost. Genome high temperature therefore, the need of and proteome analysis on Methanococcoides thermostable xylanase is crucial. Recently, a burtonii have disclosed mechanisms for its thermostable xylanase was reported from survivability at cold environment [26,27]. The Thermotogathermarum, Xyn10A with a maximal usages of cold adapted enzymes are currently activity exhibited at 95°C, pH 7.0 [17]. In the center of attention of many researchers due addition, it has demonstrated high thermostability to their natural properties that able to grow/work over broad range of pH 4.0–8.5 and temperature optimally at cold temperatures. However, studies 55-90°C upon the addition of 5 mM Ca2+. On the of archaea and cold adapted enzymes from other hand, a xylanase from Thermococcus archaea are still in infancy level compared to zilligii is reported active at 100°C and has bacteria. To date, several applications have been preferences to different substrates [18]. reported of using archaea in wastewater treatment and methane production [28,29]. DNA polymerase; the key enzyme that is Similarly, archaeal enzymes/cofactors are also responsible in molecular biology especially for reported to involve in metabolic, light-harvesting DNA amplification in polymerase chain reaction, complexes and ether-linked lipids, which show has drawn high interest in biotechnology impressive values in biotechnology applications industries. The first DNA polymerase used, Taq [30,31].

4

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

3.3 Haloarchaeal Extremozymes candidates in the industrial applications especially in food processing. Halophiles are organism that is able to thrive optimally at high salt concentration (> 0.6M NaCl; 4. BIOREMEDIATION seawater salt concentration). In this context, archaea have been discovered in several Bioremediation is a process of utilizing natural or ecological niches like Dead Sea and Great Salt genetically engineered living organisms such as Lake, where most of the isolated archaea are fungi, bacteria and archaea to transform pollutant able to adapt with the osmotic changes in their and contaminants from the environment into less environments [32,33]. Enzymes from halophiles toxic compound. Accordingly, bioremediation has remain active and stable although being exposed been proven to degrade hydrocarbon and other to high salt concentration due to the presence of aromatic compounds in soil and water. The unique properties in their proteins like high acidic success of this technology depends on the ability amino acids content, less hydrophobic surface to establish and maintain the favor of microbe to contact and presence of specific ion binding site grow and enhance the biodegradation rates in [34,9]. the contaminated environment. Hence, it is unsurprising that the suitable conditions such as Due to the ability to withstand extreme salt pH, temperature and salinity have been reported concentrations, halophiles have been first to influence the microbe growth and chosen to be applied in various industries. Many biodegradation metabolic activity [40,41]. enzymatic activities of halophilic archaea have Moreover, the physical and chemical been characterized, however no commercial characteristics of oil and oil surface also play applications have yet been developed for such crucial role to ensure the bioremediation enzymes [35]. Still, some archaeal enzymes success. Though this technology has been have triggered some potential interests, such as proven to be able to remediate contamination, the amylase of Haloarcula sp. that functions however there is a limitation for the optimally at 4.3 M salt at 50°C and known to be bioremediation process in extreme condition stable in the presence of benzene, toluene and such as high salinity and temperature. This is chloroform [36]. In addition, halophilic due to the fact that not many microorganisms galactosidases from Haloferax alicante that are have the capability to grow in these harsh active at 4M NaCl with the ability to cleave broad conditions. Archaea are one of the microbes that galactosidases excluding lactose have been long have gained much attention to remediate identified [37]. Besides, the archaeon Haloferax hydrocarbon contamination especially in the mediterranei has been reported to be able to extreme conditions. Analysis of microbial produce up to 38% Poly-β-hydroxyalkanoate community on soil sample contaminated with (PHA) compound from its dry weight grown at petroleum hydrocarbon in the European Alps, 150 g/L salt under phosphate limitation [38]. using fish-in-situ hybridization (FISH) and identification via 16S rRNA, revealed that a 3.4 Piezophilic Extremozymes number of archaea related to the orders of Methanomicrobiales, Methanosarcinales, Organisms that are able to thrive at high Methanobacteriales and Thermoplasmatales pressure are generally called as piezophilic. have been detected in that area [42]. In another Often they colonize in habitats like deep sea and study, a range of archaeal community that has extreme heat of hydrothermal vents. Piezophilic functions in hydrocarbon-degradation, production archaea are usually characterized as of surfactant and methanogenesis during the thermophilic as they are mainly being isolated displacement of oil such as Thermus, from thermophilic habitats [39]. The general Thermincola, Thermanaeromonas have been properties of piezophilic enzymes usually similar found in high-temperature oil reservoir [43]. to their temperature adaptation but with additional features; exist as multimers, smaller On a large scale, many researchers have hydrogen bonding amino acids and packed reported on the potential of archaea as hydrophobic core [9]. Paradoxically, research on biocatalyst in bioremediation [44-46]. Mainly, as piezophiles archaea are limited due to the archaea can grow in hypersaline condition and difficulties in culturing the strain at high pressure. encapsulate great catabolic activity compared to Albeit, the piezophiles are usually coupled with bacteria and fungi hence, archaea probably either high or low temperature adaptations comprise excellent selections as best possible mechanisms that making them as a great biocatalyst candidates [47]. On top of that,

5

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

archaea can growth in either high or low of incubation. Based on previous studies, these temperatures and extreme pH conditions, findings suggested that halophilic archaea have contrariwise to bacteria which are commonly the capability to degrade crude oil at high used for bioremediation but are unable to survive temperatures and are probably the most suitable in these harsh conditions [43,48]. This unique candidates to be applied in bioremediation ability clearly provides advantages for archaea process at extreme environment conditions. especially to remediate contaminations that occur in extreme environments. Fascinatingly, it 4.2 Aromatic Compound Degradation has also been reported that some archaea show high resistant towards variety of antibiotics Apart from degrading aliphatic hydrocarbon, including cycloheximide, streptomycin and archaea have also been reported to acquire the penicillin, which turn archaea as a great potential ability to degrade aromatic hydrocarbon. Several to be applied in bioremediation in the presence of studies have been conducted to isolate and antibiotic [49]. determine the archaea that could degrade aromatic hydrocarbon. It has been reported that 4.1 Hydrocarbon Biodegradation Haloarchaea Haloferax sp. has the capability to degrade phenanthrene [46,49]. Study by Studies on bioremediation using archaea Emerson et al. [53] reported that Haloferax strain have been reported previously by other D1227 isolated from soil contaminated with oil researchers [49,50]. Table 2 shows the isolated brine was able to use aromatic hydrocarbon such halophilic archaea that have been reported to as benzoate, cinnamate and phenylpropanoate demonstrate capability to degrade hydrocarbon. as carbon source with 70% degradation. Archaebacterium strain EH4 which was isolated Similarly, Bonfa et al. [44] who investigated the from sail-mash was found to be able to grow in potential of Haloferax sp. to degrade aromatic medium supplemented with 20% NaCl [50,51]. reported that this archaea was able to degrade This study reported that this archaea could grow the mixture of aromatic compound. For this and degrade eicosane up to 62% of particular study, Haloferax sp. was cultured in a biodegradation in 10 hours of generation time. In medium with aromatic compound mixture of another study, three extreme halophilic benzoic acid, p-hydroxybenzoic acid, salicylic Haloferax, Halobacterium and Halococcus have acid and mixture of polycyclic aromatic been isolated from hypersaline coastal area of hydrocarbon. It was found that this archaea was Arabian Gulf. All of these archaea are able to use able to grow and degrade these compounds. crude oil as sole carbon source for energy. This In another study, other archaea members study also demonstrates that these strains are such as Halobacterium piscisalsi, Halorubrum able to use and degrade n-alkanes and mono- ezzemoulense, Halobacterium salinarium, and polyaromatic compounds as carbon and Haloarcula hispanica, Haloferax sp., Halorubrum energy source [49]. Interestingly, these archaea sp., Haloarcula sp. isolated from Camalti Saltern, could degrade crude oil up to 47% after 3 weeks Turkey have also exhibited capability to degrade of incubation at 40-45°C. Similar observation has aromatic hydrocarbon compound [45]. It was also been reported by Tapillatu et al. [46], who reported that Halorubrum sp. and Halorubrum isolated Haloarcula and Haloferax sp. that could ezzemoulense could grow in medium degrade 95% heptadecane at 40°C after 30 days supplemented with 20% NaCl.

Table 2. Halophilic archaea that are able to grow and use hydrocarbon as carbon and energy source

Archaea Hydrocarbon References Haloferax sp. n-alkane C10-C30 [46] Haloferax sp. Heptadecane [46] Haloarcula sp. Heptadecane [46] Halobacterium sp. n-alkane C10-C34 [49] Halococcus sp. n-alkane C10-C34 [49] Strain EH4 Tetradecane [51] Hexadecane Eicosane Heneicosane Halobacterium sp. n-alkane C10-C30 [52]

6

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

4.3 Biomining There are several recent reviews on the biomining mechanisms that can be carried out by Metals and sector is considered as one of microbes. The bioleaching process of metal the major industries that is dedicated for could also contributed by the type of metals, its extraction of metal and valuable minerals from properties and mineral species [54]. There are lode, orebody, seams, and reef reserves in the two different reaction mechanisms that control world. These minerals are mine for profit the dissolution of metal : the thiosulfate and widely used in a vast range of industrial pathway and the polysulfate pathway. The applications, for instance, jewelry making, oxidation of acid-insoluble metals (, construction, ceramics, automobiles, electronics, molybdenite, tungstenite) and acid-soluble metal plastics and paper. Current mineral extraction sulfide (chalcopyrite and pyrrhotite) can be involved high temperature and chemicals which categories into the thiosulphate intermediate potentially lead to environmental pollution. pathway and polysulphide intermediate pathway Therefore, biomining using microbial has been (Fig. 1) [55]. The thiosulphate pathway is a considered to be an alternative approach to process where the metal is solubilized by ferric overcome the problem. In this process, microbes ion that generated by microbial process. In this are utilized to recover mineral resources such as pathway, the acid-insoluble metals sulfide such and other metals or minerals from low- as pyrite (FeS2), molybdenite (MoS2) or grade , waste, slag and sludge. This tungstenite (WS2) are exclusively oxidized via technique experimentally showed that it could electron extractions by ferric (Fe(III)) ions and improve recovery rate, reduce operational cost, thiosulphate is generated as main intermediate require less energy and reduce pollution product. On the other hand, the polysulphate problems. Biomining of minerals is carried out on pathway is a mechanism that the acid soluble different scale with different type of microbes metal sulfide such as sphalerite (ZnS) and including bacteria and archaea. The biomining chalcopyrite (CuS) are solubilized by process artificially can be divided into two modes combination attacked of ferric ion and proton. In namely bioleaching and bioxidation. this process, an element such as stable sulfide + Bioleaching- can be related to solubilization of cation (H2S ) is generated as main intermediate. metals such as copper, nickel, and from However, this sulphate can spontaneously ores by microorganisms. While, biooxidation is dimerize to free disulfide (H2S2) and further used for bioleached solubilized metals which oxidized by sulphur-oxidizing microbes such as wrapped/locked in sulfide minerals such as gold archaea and bacteria via higher polysulfides and and silver. polysulfide radical to generate sulfur element.

Fe2+ (a)

Oxidizing-microbe, O2

Metal sulfide 2+ 2- 2- SO 2- + H Cu + S2O3 SnO6 , S8 4 2 Fe3+ Oxidizing-microbe Oxidizing-microbe

Fe2+ (b)

Oxidizing-microbe, O2

Metal sulfide 2+ SO 2- + H Cu + H2S+(H2S2) H2Sn, S8 4 2 Fe3+ Oxidizing-microbe Oxidizing-microbe H+

Fig. 1. The schematic diagram of the bioleaching mechanisms (a) The thiosulfate pathway (b) The polysulfate mechanisms

7

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

3+ H+ Non-contact mechanisms Fe

2+ 2- Fe SO4 Fe 3+ or Fe 2+ - proton attack HS-

0 2+ S S2O3

EPS

2+ cell SO4

S0 cell

Contact mechanisms Fe 2+

Fe 3+

Fe 2+, sulfur intermediate and minerals fragment for and sulfur oxidizer microbes Cooperative leaching

Metal sulfide Leachate solution

Fig. 2. Contact and non-contact leaching mechanisms by microbes (Archaea and bacteria)

Removal of metals and minerals from can + 2 → + (1) occur in two different processes: contact and non-contact reactions [56]. Contact bioleaching is Theoretically, the mechanism can be continued where the microbe acts on the ore directly to until all the substrate orr metal sulfide (MeS) is extract metals and minerals which involve converted to product (MeSO4). The oxidation of oxidation and direct enzymatic reaction by the other metal sulfides are represented as follows: microorganisms. In this mechanism, the cells attach to the mineral surface where this process Chalcopyrite: takes place within minutes or hours. Microorganisms typically form an 4 + 17 + 2 → 4 + exopolysaccharide (EPS) layer when attach to 2( ) + 2 (2) the surface of minerals and provide a space for biooxidation reaction in the compound (Fig. 2). Pyrite: While for non-contact bioleaching, it occurs when the microbe produces some strong oxidizing 4 + 15 + 2 → 2 ( ) + chemical substances like ferric ions and 2 (3) sulphuric acid that lead to the solubilization of metals and minerals (iron and sulfur) from ore. Chalcocite: This mechanism involves oxidation of reduced 3+ metal which is mediated by ferric ions (Fe ) 2 + 5 + 2 → 4 + formed from the microbial oxidation of ferrous ion 2+ (Fe ) compounds present the mineral. In this 2 (4) matter, acidic environment is important in indirect bioleaching in order to keep the ferric ion and Covellite: other metals in solution form. This can be done through continuous oxidation of iron, sulphur, + 2 → (5) metal sulphides and carbonate in solution. Non-contact mechanism: The following equations (1-12) describe the contact and non-contact biomining mechanisms In non-contact bioleaching, the microbes of various type of metals by microorganisms: generate chemicals that will oxidize the sulfide minerals. The process for non-contact Contact mechanism: mechanism is represented by the oxidation of In this process, metal sulphides are oxidized sulphide minerals by ferric ions as shown in directly by bacteria or archaea to soluble metal equation 6. This particular reaction occurs by sulphates as shown in equation 1. the action of archaea or bacteria whereas the

8

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

chemical reaction in equation 7 occurs without Sulfolobus brierleyi which are thermophilic and any association of microbes. acidophilic archaea respectively are among the archaea that involve in bioleaching of copper and 4 + 2 + 2 → 2() + 2 molybdenum from chalcopyrite and molybdenite (6) [58,59]. Additionally, another archaea that is commonly used in biomining is Metallosphaera sedula, which is a single-cell microorganism that + () → + (7) produce enzymes to alter metal-sulfur compound and produce elemental form of the metal that can 2 + 3 + 2 → 4 + 2 (8) be used for industrial application [59]. Study by Metal dissolution takes place by a cyclic Kozubal et al. [60], who isolated Metallosphaera process between reactions shown in equation 6 strain MK1 from geothermal spring in and 7 and the generation of H+ during sulphide Yellowstone National Park indicated that this oxidation in equation 8 enhances the overall archaea showed a maximum bioleaching activity efficiency. The following equations represent under an extreme condition of pH value of 2.5 chemical oxidation processes; and temperature of 70°C. In another study, the optimum growth of Ferrosplasm athermophilum Chalcopyrite: sp. nov. isolated from leaching bioreactor was obtained when the process was carried out at temperature of 45°C and pH value of 1 [61]. Most + 2() → + of these archaea show optimum bioleaching 5 ( ) + 2 (9) activity under extreme temperature (>60°C) and the pH value below 3 (Table 3). Pyrite: The capability of archaea in bioleaching and + () → 3 + 2 (10) biooxidation activity is highly attributed by several factors such as types of archaea, quantity of Chalcocite: minerals, ore type, nutrient addition, pH, temperature, pulp density and agitation [67-69]. + () → 4 + 3 + In order to obtain high extraction yield, there is a (11) need to optimize the operating conditions which could provide favorable conditions for the Covellite: archaea growth, acid consumption and enhance metals recovery [70]. In the biomining process, + () → 4 + 3 + there are two major important factors that need 2 (12) to be considered: (1) pH and (2) temperature [71,72]. Generally, the leach dump for biomining According to Stott et al. [57] based on their study process is in acidic condition due to the presence on the bioleaching of chalcopyrite by 11 different of acidic mine water supplied during the process. microbes found that the process in archaea and On top of that, the temperature in the dump may bacteria were identical. To date, probably high due to the overheating from the thermoacidophile archaea such as Sulfolobus bioprocessing of ores, which release a great deal metallicus, Ferrroplasma, Sulfobacillus, of heat that could kill or hinder the microbes Acidianus and Metallosphaera are among growth during the process. Thus, in order to the archaea that have been reported to be increase the efficiency of biomining activity, the able to thrive in this extreme environment microbial strain that have capability to survive in [56,58]. Sulfolobus acidocaldarius and low pH and high temperature is required.

Table 3. Optimum temperature and pH for bioleaching by different extremophile archaea

Archaea Temperature (°C) pH References Ferroplasma acidophilum 35 2.2 [62] Acidianus brierly 70 2 [63] 75 6 [64] Sulfolobus acidocaldarius 65 1.3-1.7 [65] Acidianus manzaensis 65 1.5 [66]

9

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

The pH value and ores quality play a major role would provide favorable environment for archaea in leaching of material into solution [73,74]. to grow and for mineral removal. Besides, new Dynamic bioleaching can be reduced by the bioreactor with additional features like less presence of alkaline content in the materials. corrosive, cost effective material that can Study by Zhu et al. [74] on bioleaching of low- withstand high temperature and highly versatile grade ore by four different microorganisms where may be applied to any type of ore may namely, Sulfolobus metallicus, bring advantages to bioleaching process. Apart ferrodixine, Acidianus brierleyi, Leptospirillum of the reactor materials, the understanding of the ferriphilum indicated that pH and ore quality interaction between microbes available at the significantly affect the microbial growth and metal bioleaching site, which consisted of wide range recovery. It is found that, the archaea S. of different mixed culture either autotrophic, metallicus exhibits better growth in high cuprum heterotrophic, thermophilic, acidophilic and etc concentration up to 0.5%. Besides, reducing pH may be useful towards understanding to improve value 3 to 1 would enhance S. metallicus growth. the bioleaching and mineral bio-oxidation This could be due to the fact that low pH sector/industry. In principle, the continuation of provides Fe3+ and S° for microbial growth and archaeal activity exploration by determination of lead to the more proton consumption of the the proteins and metabolites as industrial mineral surface. Temperature is also one of the bioindicators for bioleaching purposes through important parameters that guarantee the omic technologies should be able to provide a bioleaching process [75]. The bioleaching comprehensive overview on the reactions that process is carried out from a wide range of occur during the process. Therefore, by temperatures from ambient to high temperatures understanding the mechanisms and interactions up to 90°C. Basically, the optimum temperature involved in the archaea, the bioleaching process for the bioleaching process is highly dependent could be optimized effectively and efficiently. on the type of archaea used in the process. Study on the effects of temperature on Cu 5. METHANE PRODUCTION BY removal by Sulfolobus sp. shows that rise of METHANONGENIC ARCHAEA temperature reaction from 50 to 75°C would enhance Cu removal from low-grade granitic Production of biomethane as renewable chalcophyrite [58]. It is found that the maximum bioenergy from anaerobic fermentation of various removal of 85% is obtained at 75°C, as organic matters such as dead animals and plant compared to other temperature tested; 59% at materials, manure, sewage and organic waste is 50°C, 63% at 60°C and 74.2% at 65°C one of the alternative approaches to overcome respectively. global energy issues. The biomethane is a non- poisonous, odorless and colorless gas, where The role of archaea in biomining industry has this gas is produced from the series of complex been proven to recover valuable minerals and anaerobic reaction of nutrient-rich substrate by metals from low-grade ore and it is now actively several bacteria and methanogenic archaea [76]. being practices in developing countries. Methanogenic archaea or methanogens are one However, there are few limitations that have of the important groups of the microorganisms been identified which can be improved in order to that play a significant role in conversion of sustain this process. The crucial limitation of carbon dioxide (CO2) and other bacteria waste bioleaching is the slow kinetics of metal recovery byproducts in order to produce methane as the by the archaea. In order to increase the reaction, final metabolic byproduct [77-79]. a new technique should be adopted by targeting on the new biocatalyst reaction that can 5.1 Methane Production accelerate the growth and metal recovery activity. This can be achievable by selecting Generally, production of biomethane involves enzymes that have (1) better activation on the three different stages, (1) conversion and mineral surface (2) enzyme inhibition activity and hydrolysis of raw materials by acidogenic (3) provide more electrons for the microbes bacteria into simpler organic acids, sugars and during the bioleaching process. On top of that, amino acids (2) production of H2, CO2 and the development of bioreactor for bioleaching acetate from organic acid by hydrogen producing process should also be taken as part of the bacteria (3) methanogenesis (Fig. 3). The approaches to improve future impact of the methanogenesis process is the formation of bioleaching process. Stirrer-tank or bioreactor methane from CO2 and acetate by methanogenic with better aeration and controlled conditions archaea. According to Liu and Whittman [80,65],

10

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

methanogenesis can occur through six different can normally be found in lower temperatures reactions, where these reactions are highly between 30–55°C. For the fourth group, the dependent on the type of methanogens and Methanosarcinales, are rod shaped methanogen substrates availability. that have the widest substrate ranges among all methanogens. Most of the Methanosarcinales 5.2 Methanogenic Archaea produce methane by disproportionating the methyl group in the organic compound or splitting There are 5 well established methanogenic acetate. Some of the group could also reduce archaea orders that involve in methanogenesis CO2 with H2. This group is found mostly in low namely, Methanobacteriales, Methanococcales, temperatures and has different types of cell Methanomircobiales, Methanosarcinales, and shapes. The last methanogen order is the Methanopyrales [80]. Table 4 shows the major Methanopyrales, which are rod-shaped, motile taxonomic groups of methanogens that play and capable of reducing CO2 and H2 for important roles during methanogenesis phase. methanogenesis. The only member for this group Methanogens of different orders contain different is M. kandleri which has been identified as a cell envelope structures, lipid compositions, thermophilic methanogenic archaea. This substrate range and other biological properties. species was reported to be able to grow at high temperatures ranging from 84–110°C. The first order which is the Methanobacteriales are generally the methane producers which use Due to the ability of methanogens to degrade H2 as electron donor and CO2 as electron organic materials efficiently, these organisms are acceptor. In most general terms, the cells are also widely been used in wastewater treatment non-motile, rod shaped and can be found in plant. Analysis on the archaea distribution in higher pH range 6 to 9. For the second order wastewater has been reported by other which is the Metanococcales, are cocci that have researchers [81,82]. Tabatabei et al. [81], who flagella and utilize CO2 and H2 for methane analyzed the archaea community in palm oil mill production. Most of these archaea have been effluent using 16S ribosomal RNA (rRNA)- isolated from marine habitats and require sea targeted fluorescent in situ hybridization salt for optimum growth. In addition, the third combined with polymerase chain reaction (PCR)- order which is the Methanomicrobiales, most of cloning found the presence of Methanosaeta sp. these archaea in this order acquire the ability to and Methanosarcina sp. cells where utilize acetate to produce methane. This group Methanosaeta concilii dominated the sample.

Fig. 3. Methane production by microorganisms (Adapted and modified from [80])

11

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

Table 4. Characteristics of major taxonomic group of methanogens [80]

Order Family Genus Temperature (°C) Methanobacteriales Methanobacteriaceae Methanobacterium 37–45 Methanobrevibacter 37-40 Methanobacter 55-65 Methanothermaceae Methanothermus 80-88 Methanococcales Methanocaldococcaceae Methanocaldococcus 35-40 Methanotorris 60-65 Methanococcaceae Methanococcus 80-85 Methanothermococcus 88 Methanomicrobacteriales Methanomicrobiaceae Methanomicrobium 40 Methanoculleus 20-55 Methanofollis 37-40 Methanogenium 15-57 Methanolacinia 40 Methanoplanus 32-40 Methanospirillaceae Methanospirillum 30-37 Methanocorpusculaceae Methanosorpusculum 30-40 Methanosarcinales Methanosarcinaceae Methanosarcina 35-60 Methanococcoides 23-35 Methanohalobium 40-55 Methanohalobphilus 35-40 Methanolobus 37 Methanmethylovorans 20-50 Methanimicrococcus 39 Methanosalsum 35-45 Methanselacaea Methanoseala 35-60 Methanopyrales Methanopyraceae Methanophyres 98

Furthermore, Vanwonterghem et al. [82] reported definitely provide more information on the activity the discovery of divergent methyl-coenzyme M and microbial involvement during the methane reductase genes in population genomes production process. recovered from anoxic environments with high methane flux that belong to a new archaeal 6. VALUE ADDED PRODUCTS phylum, the Verstraetearchaeota from palm oil mill effluent (POME). These archaea encode Archaea produce variety of secondary the genes required for methylotrophic metabolites and proteins during their methanogenesis, and may conserve energy metabolisms. These proteins and metabolites using a mechanism similar to that proposed for such as wide range of extremophile enzymes the obligate H2-dependent methylotrophic have adapted to function under extreme Methanomassiliicoccales. Even though methane conditions, which can be applied in wide range of is one of the potential negative impacts on the biotechnology applications. global warming, it has also been suggested to capture the methane and use it as a renewable 6.1 Exopolysaccharides energy source [76]. Nevertheless, research and thorough understanding are needed in order to Extracellular polymeric substances (EPS) are increase methane production and sustain the high molecular polysaccharides and major process. Since methane production involves functional component released by archaea as other microorganisms such as bacteria at early protection mechanisms against several stage of the process, thus the knowledge on environmental stress such as dessiccation, microbial ecology distribution and interaction predation and ultraviolet radiation. The EPS between bacteria and archaea are required for molecules have several industrials application better biological control of the process. The such as bioaggregation in wastewater treatment considerable attempt for example, determination process and also as gelling or emulsifying agents of microbial community structure using molecular in food industry [83,30]. The EPSs produced approaches and metabolite analysis would by microorganisms have exhibited immense

12

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

advantages, like short fermentation process, of EPSs by archaea is highly depending on the easily formed and stable emulsion [84]. fermentation condition especially types of substrates used during the fermentation process. Several extremophilic archaea mainly belong to Parallel to these findings, another study has the thermophilic and halophilic groups have been reported that the fermentation media contributed reported to produce EPSs [85,86]. Among the approximately 30% of the EPS production cost. thermophilic archaea that could produce EPSs Thus, in order to maximize the cost-effective are Thermococcus, Sulfolobus, Archaeoglobus process, utilization of cheaper substrate such as fulgidus and Thermococcus litoralis [85]. While, molasses, biomass spent grains and industrial for the halophilic archaea, Haloferax, Haloarcula, wastewater should be adopted in biotechnology Halococcus, Natronococcus, and Halobacterium industries. Hence, development and are among the most common archaea that have improvement on the archaea strains and been reported to be able to produce EPSs [87- identification of their potential usage in the high- 89]. It has been reported that archaea Haloferax value market niches such as cosmetic and sp. could produce EPS in order to remove heavy pharmaceutical should be established in order to metal from environment that contained high salt ensure the EPS from archaea is marketable. [90]. On the other hand, the common EPS producing Halomonassuch as H. maura, H. 6.2 Polyhydroxyalkanoates (PHA) eurihalina, H. ventosae and H. anticariensis have been reported to produce EPS that contained Production of PHA from microorganisms has high sulphate content and uranic acids which gain great attention globally due to its corresponding to their good gelifying agent characteristics that have high biodegradability in properties [91,92]. different environments, flexible thermoplastic

The EPSs produced from the archaea has been polymer and high potential sustainable characterized by many researchers [83,82]. It replacement production of fossil-fuel plastic. PHA was found that most of the EPSs produced by has wide range of applications based on its archaea contain heteropolysaccharide such as characteristics. Currently, PHA is used in film mannose, glucose and galactose with different packaging mainly for containers, paper coating ratio depending on the type of archaea [86,93]. and disposable plastic items such as razor, For instance, sugar analysis of EPSs produced utensils, diaper, cosmetic container and cups by Haloferaxginnonsii (ATCC 33959) indicated [94,95]. The PHA is also useful as a that the extracellular polysaccharide contained biodegradable carrier for drugs, hormones, D-Man, D-Glc, D-Gal and L-Rha in the ratio of insecticides and herbicides in agriculture industry 2:1:3 respectively. While in another study by [96]. It is can also be used in medical and Nicholaus et al. [87], who isolated Haloarcula pharmaceutical applications, for instance as japonica, which was an obligate halophilic osteosynthetic in bone plates, surgical sutures archaea revealed that EPSs produced by this and blood vessel replacement [84,80]. However, archaea consisted of mannose, galactose and there is a limitation on PHA application in gluconic acid with relative ratio of 2:3:1 medical and pharmaceutical industries due to the respectively. slow degradation and high hydraulic stability in sterile tissues [97]. In this context, PHA can be The EPSs produced by microorganisms can be synthesized by microorganisms including applied in wide range of industries. At present, archaea. Generally, PHA is produced as reserve the most well known products such as xanthan, energy during stationary phase in the presence dextran, gellan and curdlan are among the of excess carbon and during nutrient depletion products that are obtained from EPSs produced [95]. by microorganisms. Even though the EPSs have exhibited potential characteristics for industrial There are a number of producers of PHAs applications, however, these non-toxic and as shown in Table 5. Most of the PHA biodegradable EPSs only contribute a small produced by archaea are from Haloarchaea. fraction in polymer market. This is due to the high Most of the Haloarchaea, Haloarculasp, production cost and poor physiochemical Halobiforma haloterrestris strain 135T and characteristics compared to the industrial EPSs Halopiger aswanesnsis 56 exhibit high PHA from starch, cellulose, pectin and seaweed, content up to 63% of their cell dried weight. A which make the EPSs from archaea unsuitable previous study also indicated that supplying for big markets [84,85]. Besides, the production different nutrient sources during fermentation

13

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

Table 5. List of PHA archaea producers supplied with different types of nutrient sources [84]

Microorganism Carbon source Type Yield Haloarcula hispanica YE/Glc PHB 2.4% H. hispanica YE/Glc PHVB 0.58* H. marismortui YE/Glc PHB 21% Haloarcula sp. IRU1 Glc PHB 63% H. japonica T5 Glc PHB 0.5% Halobacterium noricence YE/Triptone PHB/PHVB 0.03-0.08% Halobiforma haloterrestris 135T YE/butyric acid PHB 40% H. haloterrestris 135T YE/casamino acid/proteose PHB 15% Halococcus dombrowskii YE/HyCase PHB/PHBV 0.15% Halococcus salifodinae YE/HyCase PHB/PHBV 0.05% Haloferax mediterranei YE/Glc PHB 17% H. mediterranei Glc PHVB 23% H. mediterranei Starch PHB 6.48% H. mediterranei Casamino acid/YE PHVB 1.33% H. mediterranei YE/Stach PHVB 1.74% Haloferax gibbonsii YE/Glc PHB 1.2% Haloferax volcanii YE/Glc PHB 7% Haloterrigena hispanica YE/Casamino acid PHB 0.14% Halopiger aswanesnsis 56 YE/ Sodium acetate/ butyric PHB 34% acid Natronobacterium gregoryi YE/Casamino acids PHB/PHVB 0.03-0.1% *YE: Yeast extract, Glc: Glucose could affect the PHA production in archaea [98]. a mixture of glycolipids, fatty acids, proteins, and Replacing glucose with extruded cornstarch was sugars, which act by reducing surface tension found to enhance H. mediterranei growth and (ST) and interfacial tensions between individual increased 43.3% of PHA content [99]. In another molecules at the surface and interface, study, fermentation of H. mediterranei with respectively. Biosurfactants have displayed many hydrolyzed whey, glucose and galactose in fed advantages compared to traditional chemically batch system resulted in high PHA content up to derived surfactants by being renewable, 72.8% [100]. nontoxic, biodegradable and active under a range of extreme conditions [102]. These Production of PHA from halophilic archaea is compounds have been proven can be applied in pointed to produce more advantages than non- bioremediation of oil in soil and water samples halophile microorganisms due to its ability to [103]. Besides, it can also be applied in wide operate under high salinity, which also can range of industries for instance food, cosmetic prevent traces of contamination. Apart from that, and pharmaceutical industries [104]. its applications can also reduce operation cost as only low energy is required for sterilization of the Several halophilic archaea have been identified equipment and fermentation medium. On the to produce biosurfactants at the highest salt other hand, another advantage of PHA concentration recorded [105]. Gana et al. [105] production from halophilic archaea is the simple has screened and isolated two biosurfactant polymer recovery which can be performed archaea Halovivax strain A21 and Haloarcula through hypoosmotic shock with salt-deficient strain D21 from a pond in Ain Salah, Algeria. It water. Thus, its applications are seen to greatly was found that both archaea were able to benefit the cost by reducing the downstream produce high biosurfactant at high salinity processing cost which contributes approximately condition. The capability of archaea 40% of the total production cost [101]. Haloferaxmediterranei and Haloarcula japonica to produce biosurfactant have also been reported 6.3 Biosurfactants elsewhere. Both of these archaea produced high sulphated EPS and acid heteropolysaccharide, Biosurfactants (BS) are amphiphilic compounds where high sulphated-EPS was reported produced by a wide range of organisms including inhibited viral penetration into the cell [106]. In archaea. These extracellular compounds contain another study, Selim et al. [107] has successfully

14

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

isolated 29 strains of biosurfactant haloalkaphilic products. The presence of this halocins was archaea from water and sediment of Soda found to inhibit the undesirable halophilic growth Lakes of Wadi An Natrun, Egypt. The isolates [112]. Additionally, halocins which are produced have been identified from Natrococcus, by archaea mostly acquire tolerant to high salt Natronolimnobius, Halorubrum and Natromonas concentrations where they inhibit growth of genera, where most of these archaea have undesirable strains of other haloarchaea thus shown their capability to emulsify crude oil. promoting them as great potential to be applied Furthermore, the isolated archaea can also stand in salted food preservation. extreme conditions hence they are proposed to be good candidates to be applied in 7. CONCLUSION bioremediation especially to remediate harsh environment contaminated sites. Recently, an As a summary for this review, it is clear that extreme halophilic archaeon Natrialba sp. that archaea which have unique characteristics cater has the capability to emulsify both aliphatic and immense potentials to be applied in variety of aromatic hydrocarbon has been isolated from industries. Their capability to grow at extreme contaminated saline water [108]. It has been conditions provides advantages to these reported that this archaea is probably a potential organisms to be applied in the environmental candidate to be applied for remediation biotechnology fields especially for bioremediation especially with high aromatic hydrocarbons at and biomining activity. Among the archaea extreme environment conditions. members, Haloferax, Haloarcula, Halobacterium and Sulfolobus play important roles in 6.4 Antibiotics bioremediation and biomining of mineral processes. Similarly, peptides, proteins and Most antibiotic peptides by archaea can be found enzymes (PHA, biosurfactants, extremophile widely amongst Haloarchaea (termed halocins) enzymes and archeocins) produced by archaea and more recently from the Sulfolobus genus can potentially be used in other industries such (sulfolobicins) [109]. Furthermore, other archaea as food processing, agriculture, and such as Natrinema sp, an extreme halophilic pharmaceutical industry. Although numerous archaea have also been reported to be able to studies and reports on archael studies have been produce halocin [110]. The production of halocin made recently, more information especially on by Haloferax larsenii has also been reported by the gene regulation, enzymes and metabolites previous study [111]. The halocin produced by H. related to the archaea metabolisms and activity larsenii isolated from Pachpadra in Rajasthan are still required in order to improve the efficiency has been characterized and it was found that this of the process. It is imperative that we continue halocin was stable up to 100°C and in pH range to study archaea as comprehensive 5.0-9.0. Halocin are either peptide (<10kDa: investigations will likely unveil additional microhalochin) or protein (>10kDa) antibiotics industrial capabilities resulting in inexpensive and that commonly produced by members of archaea eco-friendly alternative resources. Overall, it is Halobacteriaceae. The microhalochins are clear that archaea serve as great biocatalysts hydrophobic and robust, where they can undergo that can be applied in wide range of industries. desaltation without losing their activities. In addition, it is also relatively insensitive to heat COMPETING INTERESTS and can be stored for a long period of time up to 7 years [112]. The antimicrobial property of Authors have declared that no competing halochin has narrow range that only affects their interests exist. close relatives. As for sulfolobicins, the antibiotic activity is predominantly associated with the cells REFERENCES [113]. The apparent sulfolobicin antimicrobial activity is recorded to be restricted only to other 1. Ng SY, Zolghadr B, Driessen AJ, Albers members of Sulfolobales. To date, the SV, Jarrell KF. Cell surface structures of application of this antibiotic is not yet well archaea. Journal of Bacteriology. 2008; established. However, a particular application 190(18):6039-6047. that is relevant to halocin producing archaea is 2. Woese CR, Fox GE. Phylogenetic the textile industry, where high amount of salt is structure of the prokaryotic domain: The used during the tanning process. This condition primary kingdoms. Proceedings of the could allow the growth of other halophilic National Academy of Sciences. 1977; organisms, which resulted to the damage of the 74(11):5088-5090.

15

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

3. Woese CR, Kandler O, Wheelis ML. Letters in Applied Microbiology. 2013; Towards a natural system of organisms: 57(4):336-343. Proposal for the domains Archaea, 15. Constantito HR, Brown SH, Kelly RM. Bacteria, and Eucarya. Proceedings of the Purification and characterisation of an a- National Academy of Sciences of the glucosidase from a hyperthermophilic United States of America. 1990;87(12): archaebacterium Pyrococcus furiosus, 4576-4579. exhibiting a temperature optimum of 105 4. Reeve JN, Bailey KA, Li Wt, Marc F, and 115C. Journal of Bacteriology. 1990; Sandman K, Soares DJ. Archaeal 172(7):3654-3660. histones: structures, stability and DNA 16. Viikari L, Kantelinen A, Sundquist J, Linko binding. Biochemical Society Transactions. M. Xylanases in bleaching: From an idea 2004;32(2):227-230. to the industry. FEMS Microbiology 5. Lecompte O, Ripp R, Thierry JC, Moras D, Reviews. 1994;13(2):335-350. Poch O. Comparative analysis of 17. Shi H, Zhang Y, Li X, Huang Y, Wang L, ribosomal proteins in complete genomes: Wang Y, Ding H, Wang F. A novel highly An example of reductive evolution at the thermostable xylanase stimulated by Ca2+ domain scale. Nucleic Acids Research. from Thermotoga thermarum: Cloning, 2002;30(24):5382-5390. expression and characterization. 6. Makarova KS, Koonin EV. Comparative Biotechnology for Biofuels. 2013;6(26):1-9. genomics of archaea: How much have we 18. Uhl AM, Daniel RM. The first description of learned in six years, and what's next? an archaeal hemicellulase: the xylanase Genome Biology. 2003;4(8):115-115. from Thermococcus zilligii strain AN1. 7. Elleuche S, Schröder C, Sahm K, Extremophiles. 1999;3(4):263-267. Antranikian G. Extremozymes — 19. Chien A, Edgar. D.B., Trela JM. biocatalysts with unique properties from Deoxyribonucleic acid polymerase from the extremophilic microorganisms. Current extreme Thermus aquaticus. Opinion in Biotechnology. 2014;29:116- Journal of Bacteriology.1976;127(3):1550- 123. 1557 8. Egorova K, Antranikian G. Industrial 20. Kim KP, Bae H, Kim IH, Kwon ST. Cloning, relevance of thermophilic Archaea. Current expression, and PCR application of DNA Opinion in Microbiology. 2005;8(6):649- polymerase from the hyperthermophilic 655. archaeon, Thermococcus celer. 9. Reed CJ, Lewis H, Trejo E, Winston V, Biotechnology Letters. 2011;33(2):339- Evilia C. Protein adaptation in archeal 346. extremophiles. Archaea. 2013;1-14. 21. Cambon-Bonavita MA, Schmitt P, Zieger 10. Eichler J. Biotechnological uses of M, Flaman JM, Lesongeur F, Gérard R, archaeal extremozymes. Biotechnology Bindel D, Frisch N, Lakkis Z, Dupret D, Advances. 2001;19(4):261-278. Barbier G, Quérellou J. Cloning, 11. Lévêque E, Janeček Š, Haye B, Belarbi A. expression, and characterization of DNA Thermophilic archaeal amylolytic enzymes. polymerase I from the hyperthermophilic Enzyme and Microbial Technology. 2000; archaea Thermococcus fumicolans. 26(1):3-14. Extremophiles. 2000;4(4):215-225. 12. Bertoldo C, Antranikian G. Starch- 22. Griffiths K, Nayak S, Park K, Mandelman hydrolyzing enzymes from thermophilic D, Modrell B, Lee J, Ng B, Gibbs MD, archaea and bacteria. Current Opinion in Bergquist PL. New high fidelity Chemical Biology. 2002;6(2):151-160. polymerases from Thermococcus species. 13. Koch R, Zablowski P, Spreinat A, Protein Expression and Purification. 2007; Antranikian G. Extremely thermostable 52(1):19-30. amylolytic enzyme from the 23. Dietrich J, Schmitt P, Zieger M, Preve B, archaebacterium Pyrococcus furiosus. Rolland JL, Chaabihi H, Gueguen Y. PCR FEMS Microbiology Letters. 1990;71(1-2): performance of the highly thermostable 21-26. proof-reading B-type DNA polymerase 14. Han T, Zeng F, Li Z, Liu L, Wei M, Guan Q, from Pyrococcus abyssi. FEMS Liang X, Peng Z, Liu M, Qin J, Zhang S, Microbiology Letters. 2002;217(1):89-94. Jia B. Biochemical characterization 24. Cavicchioli R. Cold-adapted archaea. of a recombinant pullulanase from Nature Review Microbiology. 2006;4(5): Thermococcus kodakarensis KOD1. 331-343.

16

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

25. De Maayer P, Anderson D, Cary C, Cowan Environmental Technology. 2010;31(8-9): DA. Some like it cold: Understanding the 825-834. survival strategies of psychrophiles. EMBO 36. Fukushima T, Mizuki T, Echigo A, Inoue A, Reports. 2014;15(5):508-517. Usami R. Organic solvent tolerance of 26. Allen MA, Lauro FM, Williams TJ, Burg D, halophilic α-amylase from a Haloarchaeon, Siddiqui KS, De Francisci D, Chong KWY, Haloarcula sp. strain S-1. Extremophiles. Pilak O, Chew HH, De Maere MZ, Ting L, 2005;9(1):85-89. Katrib M, Ng C, Sowers KR, Galperin MY, 37. Holmes ML, Scopes RK, Moritz RL, Anderson IJ, Ivanova N, Dalin E, Martinez Simpson RJ, Englert C, Pfeifer F, Dyall- M, Lapidus A, Hauser L, Land M, Smith ML. Purification and analysis of an Thomas T, Cavicchioli R. The genome extremely halophilic β-galactosidase from sequence of the psychrophilic archaeon, Haloferax alicantei. Biochimica et Methanococcoides burtonii: The role of Biophysica Acta (BBA) - Protein Structure genome evolution in cold adaptation. The and Molecular Enzymology. 1997;1337(2): ISME Journal. 2009;3(9):1012-1035. 276-286. 27. Goodchild A, Raftery M, Saunders NFW, 38. Don TM, Chen CW, Chan TH. Preparation Guilhaus M, Cavicchioli R. Biology of the and characterization of poly cold adapted archaeon, Methanococcoides (hydroxyalkanoate) from the fermentation burtoniidetermined by proteomics using of Haloferax mediterranei. Journal of Liquid Chromatography-Tandem Mass Biomaterials Science, Polymer Edition. Spectrometry. Journal of Proteome 2006;17(12):1425-1438. Research. 2004;3(6):1164-1176. 39. Fang J, Zhang L, Bazylinski DA. Deep- 28. Fredriksson NJ, Hermansson M, Wilén sea piezosphere and piezophiles: BM. Diversity and dynamics of Archaea in Geomicrobiology and biogeochemistry. an activated sludge wastewater treatment Trends in Microbiology. 2010;18(9):413- plant. BMC Microbiology. 2012;12(1):140. 422. 29. McKeown RM, Scully C, Enright AM, 40. Thavarasi R, Jayalakshmi S, Chinalia FA, Lee C, Mahony T, Collins G, Balasubramanian T, Banat IM. Effect of O'Flaherty V. Psychrophilic methanogenic salinity, temperature, pH and crude oil community development during long-term concentration on biodegradation of crude cultivation of anaerobic granular biofilms. oil by Pseudomonas aeruginosa. Journal The ISME Journal. 2009;3:1231-1242. of Biological and Environmental Science. 30. Patel A, Prajapati JB. Food and 2007;1(2):51-57. health application of exopolysaccharides 41. Hamzah A, Rabu A, Azmy RFHR, Yussoff produced by lactic acid bacteria. Advances NA. Isolation and characterization of in Dairy Reserch. 2013;1(2):1-7. bacteria degrading Sumandak and South 31. Cavicchioli R, Siddiqui KS, Andrews D, Angsi oils. Sains Malaysiana. 2010;39(2): Sowers KR. Low-temperature 161-168. extremophiles and their applications. 42. Zhang DC, Mörtelmaier C, Margesin R. Current Opinion in Biotechnology. 2002; Characterization of the bacterial archaeal 13(3):253-261. diversity in hydrocarbon-contaminated soil. 32. Oren A, Gurevich P. Dynamics of a bloom Science of The Total Environment. 2012; of halophilic archaea in the Dead Sea. 421–422:184-196. Hydrobiologia. 1995;315(2):149-158. 43. Lin J, Hao B, Cao G, Wang J, Feng Y, Tan 33. Tazi L, Breakwell DP, Harker AR, Crandall X, Wang W. A study on the microbial KA. Life in extreme environments: community structure in oil reservoirs microbial diversity in Great Salt Lake, developed by water flooding. Journal of Utah. Extremophiles. 2014;18(3):525-535. Petroleum Science and Engineering. 2014; 34. Siglioccolo A, Paiardini A, Piscitelli M, 122:354-359. Pascarella S. Structural adaptation of 44. Bonfá MRL, Grossman MJ, Mellado E, extreme halophilic proteins through Durrant LR. Biodegradation of aromatic decrease of conserved hydrophobic hydrocarbons by Haloarchaea and their contact surface. BMC Structural Biology. use for the reduction of the chemical 2011;11(50):1-12. oxygen demand of hypersaline petroleum 35. Oren A. Industrial and environmental produced water. Chemosphere. 2011; applications of halophilic microorganisms. 84(11):1671-1676.

17

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

45. Erdoğmuş SF, Mutlu B, Korcan SE, Güven – a presentation. K, Konuk M. (2013) Aromatic hydrocarbon Biotechnology Reports. 2014;4:107-119. degradation by halophilic archaea isolated 56. Mikkelsen D, Kappler U, Webb RI, Rasch from Çamaltı Saltern, Turkey. Water, Air, & R, McEwan AG, Sly LI. Visualisation of Soil Pollution. 2013;224(3):1449. pyrite leaching by selected thermophilic 46. Tapilatu YH, Grossi V, Acquaviva M, archaea: Nature of microorganism– Militon C, Bertrand JC, Cuny P. Isolation ore interactions during bioleaching. of hydrocarbon-degrading extremely Hydrometallurgy. 2007;88(1–4):143-153. halophilic archaea from an uncontaminated 57. Stott MB, Sutton DC, Watling HR, hypersaline pond (Camargue, France). Franzmann PD. Comparative leaching of Extremophiles. 2010;14(2):225-231. chalcopyrite by selected acidophilic 47. Fathepure BZ. Recent studies in microbial bacteria and archaea. Geomicrobiology degradation of petroleum hydrocarbons in Journal. 2003;20(3):215-230. hypersaline environments. Frontiers in 58. Abhilash, Ghosh A, Pandey BD. Microbiology. 2014;5(173):1-16. Bioleaching of low grade granitic 48. Andrei AŞ, Banciu HL, Oren A. Living with chalcopyrite ore by hyperthermophiles: salt: Metabolic and phylogenetic diversity Elucidation of kinetics-mechanism. of archaea inhabiting saline ecosystems. Metallurgical Research and Technology. FEMS Microbiology Letters. 2012;330(1): 2015;112(5):1-14. 1-9. 59. Auernik KS, Maezato Y, Blum PH, Kelly 49. Al-Mailem DM, Sorkhoh NA, Al-Awadhi H, RM. The Genome Sequence of the metal- Eliyas M, Radwan SS. Biodegradation of mobilizing, extremely thermoacidophilic crude oil and pure hydrocarbons by archaeon Metallosphaera sedulaprovides extreme halophilic archaea from pnsights into bioleaching-associated hypersaline coasts of the Arabian Gulf. metabolism. Applied and Environmental Extremophiles. 2010;14(3):321-328. Microbiology. 2008;74(3):682-692. 50. Elevi R, Assa P, Birbir M, Ogan A, Oren A. 60. Kozubal M, Macur RE, Korf S, Taylor WP, Characterization of extremely halophilic Ackerman GG, Nagy A, Inskeep WP. Archaea isolated from the Ayvalik Isolation and distribution of a novel iron- Saltern, Turkey. World Journal of oxidizing crenarchaeon from acidic Microbiology and Biotechnology. 2004; geothermal springs in Yellowstone 20(7):719-725. National Park. Applied and Environmental 51. Bertrand JC, Almallah M, Acquaviva M, Microbiology. 2008;74(4):942-949. Mille G. Biodegradation of hydrocarbons 61. Zhou H, Zhang R, Hu P, Zeng W, Xie Y, by an extremely halophilic Wu C, Qiu G. Isolation and archaebacterium. Letters in Applied characterization of Ferroplasma Microbiology. 1990;11(5):260-263. thermophilum sp. nov., a novel extremely 52. Al-Mailem DM, Sorkhoh NA, Marafie M, Al- acidophilic, moderately thermophilic Awadhi H, Eliyas M, Radwan SS. Oil archaeon and its role in bioleaching phytoremediation potential of hypersaline of chalcopyrite. Journal of Applied coasts of the Arabian Gulf using Microbiology. 2008;105(2):591-601. rhizosphere technology. Bioresource 62. Golyshina OV, Pivovarova TA, Karavaiko Technology. 2010;101(15):5786-5792. GI, Kondratéva TF, Moore ER, Abraham 53. Emerson D, Chauhan S, Oriel P, Breznak WR, Lünsdorf H, Timmis KN, Yakimov JA. Haloferax sp. D1227, a halophilic MM, Golyshin PN.Ferroplasma acidiphilum Archaeon capable of growth on aromatic gen. nov., sp. nov., an acidophilic, compounds. Archives of Microbiology. autotrophic, ferrous-iron-oxidizing, cell- 1994;161(6):445-452. wall-lacking, mesophilic member of the 54. Fu K, Ning Y, Chen S, Wang Z. Ferroplasmaceae fam. nov., comprising a Bioleaching of different copper sulphide distinct lineage of the Archaea. minerals and their physicochemical International Journal of Systematic and properties dependence. Mineral Evolutionary Microbiology. 2000;50(3): Processing and Extractive Metallurgy. 997-1006. 2016;125(1):1-4. 63. Konishi Y, Yoshida S, Asai S. Bioleaching 55. Tao H, Dongwei L. Presentation on of pyrite by acidophilic thermophile mechanisms and applications of Acidianus brierleyi. Biotechnology and chalcopyrite and pyrite bioleaching in Bioengineering. 1995;48(6):592-600.

18

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

64. Huber T, Faulkner G, Hugenholtz P. (2004) of Nonferrous Metals Society of China. Bellerophon: A program to detect chimeric 2013;23(8):2383-2388. sequences in multiple sequence 75. Willner J, AFornalczyk A. Extraction of alignments. Bioinformatics. 2004;20:2317- metals from electronic waste by bacterial 2319. leaching. Environment Protection 65. Börje Lindström E, Wold S, Kettaneh-Wold Engineering. 2013;39(1):197-206. N, Sääf S. Optimization of pyrite 76. Balat M, Balat H. Biogas as a Renewable bioleaching using Sulfolobus Energy Source—A review. Energy acidocaldarius. Applied Microbiology and Sources, Part A: Recovery, Utilization, and Biotechnology. 1993;38(5):702-707. Environmental Effects. 2009;31(14):1280- DOI: 10.1007/bf00182813 1293. 66. Ding J, Zhang R, Yu Y, Jin D, Liang C, Yi 77. Merlin Christy P, Gopinath LR, Divya D. A Y, Zhu W, Xia J. A novel acidophilic, review on anaerobic decomposition and thermophilic iron and sulfur-oxidizing enhancement of biogas production through archaeon isolated from a hot spring of enzymes and microorganisms. Renewable tengchong, yunnan, China. Brazilian and Sustainable Energy Reviews. 2014; Journal of Microbiology. 2011;42(2):514- 34:167-173. 525. 67. Bosecker K. Bioleaching: metal 78. Goswami R, Chattopadhyay P, Shome A, solubilization by microorganisms. FEMS Banerjee SN, Chakraborty AK, Mathew Microbiology Reviews. 1997;20(3-4):591- AK, Chaudhury S. An overview of physico- 604. chemical mechanisms of biogas 68. Fang D, Zhao L, Yang ZQ, Shan HX, Gao production by microbial communities: A Y, Yang Q. Effect of sulphur concentration step towards sustainable waste on bioleaching of heavy metals from management. 3 Biotech. 2016;6(72):1-12. contaminated dredged sediments. 79. Ali Shah F, Mahmood Q, Maroof Shah M, Environmental Technology. 2009;30(12): Pervez A, Ahmad Asad S. Microbial 1241-1248. ecology of anaerobic digesters: The key 69. Chen SY, Lin JG. Effect of substrate players of anaerobiosis. The Scientific concentration on bioleaching of metal- World Journal. 2014;1-21. contaminated sediment. Journal of 80. Liu Y, Whitman WB. Metabolic, Hazardous Materials. 2001;82(1):77-89. phylogenetic, and ecological diversity of 70. Choi YS, Kim JJ, Kim MJ, Son J, Kim GH. the methanogenic archaea. Annals of the Optimization of bioleaching conditions for New York Academy of Sciences. 2008; metal removal from CCA-treated wood by 1125(1):171-189. using an unknown Polyporales sp. 81. Tabatabaei M, Rahim RA, Abdullah N, KUC8959. Journal of Environmental Wright ADG, Shirai Y, Sakai K, Sulaiman Management. 2013;121:6-12. A, Hassan MA Importance of the 71. Johnson DB, Okibe N, Wakeman K, Yajie methanogenic archaea populations in L. Effect of temperature on the bioleaching anaerobic wastewater treatments. of chalcopyrite concentrates containing Process Biochemistry. 2010;45(8):1214- different concentrations of silver. 1225. Hydrometallurgy. 2008;94(1–4):42-47. 82. Vanwonterghem I, Evans PN, Parks DH, 72. Yang T, Xu Z, Wen J, Yang L. Factors Jensen PD, Woodcroft BJ, Hugenholtz P, influencing bioleaching copper from waste Tyson GW Methylotrophic printed circuit boards by Acidithiobacillus methanogenesis discovered in the ferrooxidans. Hydrometallurgy. 2009; archaeal phylum Verstraetearchaeota. 97(1–2):29-32. Nature Microbiology. 2016;16170:1-9. 73. Plumb JJ, Muddle R, Franzmann PD. 83. Llamas I, Amjres H, Mata JA, Quesada E, Effect of pH on rates of iron and sulfur Bejar V. The potential biotechnological oxidation by bioleaching organisms. applications of the exopolysaccharide Minerals Engineering. 2008;21(1):76-82. produced by the halophilic bacterium 74. Zhu W, Xia Jl, Peng A, Nie Z, Qiu G. Halomonas almeriensis. Molecules. 2012; Characterization of apparent sulfur 17:7103-7120. oxidation activity of thermophilic archaea in 84. Poli A, DiDonato P, Abbamondi GR, bioleaching of chalcopyrite. Transactions Nicolaus B. Synthesis, production, and

19

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

biotechnological application of from two thermophilic archaea belonging to exopolysachharides and polyhydroxy- the genus Sulfolobus. FEMS Microbiology alkanoates by archaea. Archaea. 2011; Letters. 1993;109;203-206. 1-13. 94. Bugnicourt E, Cinelli P, Lazzeri A, Alvarez 85. Nicolaus B, Kambourova M, Oner ET. V. Polyhydroxyalkanoate (PHA): Review Exopolysaccharides from extremophiles: of synthesis, characteristics, processing From fundamentals to biotechnology. and potential applications in packaging. Environmental Technology. 2010;31(10): Express Polymer Letters. 2014;8(11):791- 1145-1158. 808. 86. Parolis H, Parolis LAS, Boán IF, 95. Singh Saharan B, Grewal A, Kumar Rodríguez-Valera F, Widmalm G, Manca P. Biotechnological production of MC, Jansson PE, Sutherland IW. The polyhydroxyalkanoates: A review on trends structure of the exopolysaccharide and latest developments. Chinese Journal produced by the halophilic Archaeon of Biology. 2014;1-18. Haloferax mediterranei strain R4 (ATCC 96. Yogesh C, Pathak B, Fulekar MH. PHA- 33500). Carbohydrate Research. 1996; Production application and its 295:147-156. bioremediation in environment. 87. Nicolaus B, Lama L, Esposito E, Manca International Science Congress MC, Improta R, Bellitti MR, Duckworth AW, Association. 2012;2:46-52. Grant WD, Gambacorta A. Haloarcula spp 97. Williams SF, Martin DP. Applications of able to biosynthesize exo- and polyhydroxyalkanoates (PHA) in medicine endopolymers. Journal of Industrial and pharmacy.Bioplymer Online. 1-38. Microbiology and Biotechnology. 1999; 98. Hermann-Krauss C, Koller M, Muhr A, Fasl 23(6):489-496. H, Stelzer F, Braunegg G. Archaeal 88. Anton J, Meseguer I, Rodriguez-Valera F. production of polyhydroxyalkanoate (PHA) Production of an extracellular co- and terpolyesters from biodiesel polysaccharide by Haloferax mediterranei. industry-derived by-products. Archaea. Applied and Environmental Microbiology. 2013;1-10. 1999;2831-2386. 99. Huang TY, Duan KJ, Huang SY, Chen 89. Jachlewski S, Jachlewski WD, Linne U, CW. Production of polyhydroxyalkanoates Bräsen C, Wingender J, Siebers B. from inexpensive extruded rice bran Isolation of extracellular polymeric and starch by Haloferax mediterranei. substances from biofilms of the Journal of Industrial Microbiology and Thermoacidophilic archaeon Sulfolobus Biotechnology. 2006;33(8):701-706. acidocaldarius. Frontiers in Bioengineering 100. Koller M, Hesse P, Bona R, Kutschera C, and Biotechnology. 2015;3:1-11. Atlić A, Braunegg G. Potential of various 90. Popescu G, Dumitru L. Biosorption of archae- and eubacterial strains as some heavy metals from media with high industrial polyhydroxyalkanoate producers salt concentrations by halophilic archaea. from whey. Macromolecular Bioscience. Biotechnology and Biotechnological 2007;7(2):218-226. Equipment. 2009;791-795. 101. Choi JI, Lee SY. Process analysis and 91. Arias S, del Moral A, Ferrer MR, Tallon R, economic evaluation for Poly(3- Quesada E, Béjar V. Mauran, an hydroxybutyrate) production by exopolysaccharide produced by the fermentation. Bioprocess Engineering. halophilic bacterium Halomonas maura, 1997;17(6):335-342. with a novel composition and interesting 102. Cameotra SS, Makkar RS, Kaur J, Mehta properties for biotechnology. SK. Synthesis of biosurfactants and their Extremophiles. 2003;7(4):319-326. advantages to microorganisms and 92. Mata JA, Béjar V, Llamas I, Arias S, mankind. In: Sen R (ed) Biosurfactants. Bressollier P, Tallon R, Urdaci MC, Springer New York, New York, NY. 2010; Quesada E. Exopolysaccharides produced 261-280. by the recently described halophilic 103. Van Hamme JD, Urban J. Biosurfactants in bacteria Halomonas ventosae and bioremediation. In: Singh A, Kuhad RC, Halomonas anticariensis. Research in Ward OP (eds) Advances in Applied Microbiology. 2006;157(9):827-835. Bioremediation. Springer Berlin 93. Nicolaus B, Manca MC, Romano I, Lama Heidelberg, Berlin, Heidelberg. 2009;73- L. Production of an exopolysaccharide 89.

20

Kassim et al.; JAMB, 5(2): 1-21, 2017; Article no.JAMB.35591

104. Nitschke M, Costa S. Biosurfactants in salinity. Extremophiles. 2015;19:1109- food industry. Trends in Food Science & 1120. Technology. 2007;18(5):252-259. 109. O'Connor EM, Shand RF. Halocins and 105. Kebbouche-Gana S, Gana ML, Khemili S, sulfolobicins: The emerging story of Fazouane-Naimi F, Bouanane NA, archaeal protein and peptide antibiotics. Penninckx M, Hacene H. Isolation and Journal of Industrial Microbiology and characterization of halophilic Archaea able Biotechnology. 2002;28(1):23-31. to produce biosurfactants. Journal of 110. Karthikeyan P, Bhat SG, Chandrasekaran Industrial Microbiology & Biotechnology. M. Halocin SH10 production by an extreme 2009;36(5):727-738. haloarchaeon Natrinema sp. BTSH10 106. Riccio R, Kinnel RB, Bifulco G, Scheuer isolated from salt pans of South India. PJ. Kakelokelose, a sulfated mannose Saudi Journal of Biological Sciences. polysaccharide with anti-HIV activity from 2013;20(2):205-212. the Pacific tunicate Didemnum molle. 111. Kumar V, Saxena J, Tiwari SK. Description Tetrahedron Letters. 1996;37(12):1979- of a halocin-producing Haloferax larsenii 1982. HA1 isolated from Pachpadra salt lake in 107. Selim SA, El-Alfy SM, Hagagy NI, Rajasthan. Archives of Microbiology. 2016; Hassanin AAI, Khattab RM, El-Meleigy ES, 198(2):181-192. Aziz MHA, Maugeri L. Oil-biodegradation 112. Shand RF, Leyva KJ. Peptide and Protein and biosurfactant production by Antibiotics from the Domain Archaea: haloalkaphilic archaea isolated from Soda Halocins and Sulfolobicins. In: Riley MA, Lakes of the Wadi An Natrun, Egypt. Chavan MA (eds) Bacteriocins: Ecology Journal of Pure and Applied Microbiology. and Evolution. Springer Berlin Heidelberg, 2012;6(3):1-11. Berlin, Heidelberg. 2007;93-109. 108. Khemili-Talbi S, Kebbouche-Gana S, 113. Atanasova NS, Pietilä MK, Oksanen HM. Akmoussi-Toumi S, Angar Y, Gana ML. Diverse antimicrobial interactions of Isolation of an extremely halophilic halophilic archaea and bacteria extend archeaon Natrialba sp. C21 able to over geographical distances and cross the degrade aromatic compounds and to domain barrier. Microbiology Open. 2013; produce stable biosurfactant at high 2(5):811-825. ______© 2017 Kassim et al.; This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Peer-review history: The peer review history for this paper can be accessed here: http://sciencedomain.org/review-history/20731

21