An Emphasis on Xenobiotic Degradation in Environmental Clean Up

ediation & m B re i o o i d B e

f g Jaiswal, J Bioremed Biodegrad 2011, S11

r Journal of o

t r

i DOI: 10.4172/2155-6199.S11-001

o u

o J ISSN: 2155-6199 Bioremediation & Biodegradation

Review Article OpenOpen Acc Accessess An Emphasis on Xenobiotic Degradation in Environmental Clean up Y.M.Varsha1*, Naga Deepthi CH2 and Sameera Chenna3 1School of Chemical and Biotechnology, SASTRA University, India 2Department of Microbiology, Andhra University, Visakhapatnam, India 3Department of Biotechnology, SVKP & Dr. K.S.Raju Arts and Science College, India

Abstract Setting up of new industries or expansion of existing industrial establishments resulted in the disposal of industrial effluents, which discharge untreated effluents causing air, water, soil and soil solid waste pollution. These disposed materials have high persistence capacities and also can change in to toxic recalcitrant up on combining with other eco-materials or manmade products. Remediation is the only way to tackle these so called xenobiotic compounds and to reduce the hazards caused by them. Even though, several practices have been implemented for degrading these recalcitrants, bioremediation step is proved to show the significa t impact on them. Giving a brief note on types of xenobionts and their impact on the environment, this study attempts to highlight on different xenobiotic degradation methods like bacterial bioremediation, phycoremediation, phytoremediation, photoremediation etc.

Keywords: Remediation; Industrial effluents; Xenobiotics; Biosorp- chemical and pharma industries like coal refineries, phenol tion; Photoremediation; Eco-industrial parks manufacturing, pharmaceuticals, dying, petrochemical, pulp mill etc., include wide variety of organic chemicals like phenol Introduction and various substituted phenol. Phenol is the simplest aromatic Pollution consequence on environ compound with hydroxyl group attached to the benzene [8]. Phenol is one among the most prevalent chemical and pharma pollutants, In early times, we had an unlimited abundance of land and due to its toxicity even at lower concentrations and formation resources; today, due to our carelessness and negligence in using them of substituted compounds during oxidation and disinfection however, the resources in the world show, in lesser degree [1]. The processes. Its direct effects on the environment include depletion of quick growth of various industries in the past century has extremely ozone layer, effect on the earth’s heat balance, reduced visibility and increased the release of toxic waste effluents in to water bodies along adding acidic air pollutants to the atmosphere [9]. Phenol removal with ground water [2]. Environmental pollution caused by the release of a these wide range of compounds (i.e. persistent organic pollutants, from the industrial wastewaters is very much necessary, prior to POPs) from industries are creating disturbance to the ecosystem [3], the wastewater discharge, so as to decrease all these effects. Phenol causing climatic changes, reduction of water levels in the ground as well being a carcinogenic compound requires biodegradation method as oceans, melting of icecaps, global warming, ozone layer depletion which results in minimum secondary metabolites and harmless due to photochemical oxidation etc. [4,5] and this made ecologists to end products [10]. Several studies and extensive investigation on focus more on impacts of pollution and its reduction. biodegradation of phenol and its derivative compounds have shown that phenol can be aerobically degraded by a wide variety of pure In some cases, industrial effluent releases are well regulated cultures of microorganisms [11]. (e.g., industrial emissions) while in other they are accidental (e.g., chemical or oil spills) which may be lethal and persistent in terrestrial 2. Plastics: Derek Pullen, a conservator at the Tate Gallery, explains, and aquatic environments. Substances in the environment are “Plastics are giant molecules held together by forces which can derived either by biogenic or anthropogenic sources. Anthropogenic be broken by attacking energy forces such as light” [12]. Plastics compounds (synthetic) plays a major role in polluting the environment are durable and degrade very slowly due to the molecular bonds [6]. Xenobiotics are anthropogenic compounds found in living systems and interactions. Plastics are made of polystyrene and polyvinyl or in the environment which are not natural and are unusually present chloride, polyethylene and its derivatives. Nowadays plastics (from in high concentrations. The potential health hazard of a xenobiotic crude oil) are used as fuels in industries since it breaks down in to compound is a function of its persistence in the environment as well as liquid hydrocarbons [13]. Microbial degradation of plastics gained the toxicity of the chemical class [7]. The issue of xenobiotics (and their importance in the last few years, but the fragmented compounds metabolites) in the environment, has been a growth area for research in released by these also lead to further environmental issues. Hence environmental chemistry for several years.

Sources of xenobiotics *Corresponding author: Y.M.Varsha, School of Chemical and Biotechnology, SASTRA University, India, E-mail: [email protected] Direct sources: The prime direct source of xenobiotics is wastewater and solid residual releases from the industries like chemical Received September 02, 2011; Accepted October 03, 2011; Published October and pharma, plastics, paper and pulp mills, textile mills, agricultural 05, 2011 (enhancement products like pesticides, herbicides etc.) (Figure 1). Citation: Varsha YM, Naga Deepthi CH, Chenna S (2011) An Emphasis on Xenobiotic Degradation in Environmental Clean up. J Bioremed Biodegrad Some of the common residual compounds in the wastewater and S11:001. doi:10.4172/2155-6199.S11-001 other effluents are Phenol, hydrocarbons, different dyes, paint effluents, Copyright: © 2011 Varsha YM, et al. This is an open-access article distributed Pesticides and Insecticides etc. under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the 1. Phenol: The natural water sources from the effluents of various original author and source are credited.

J Bioremediat Biodegrad, an open access journal Special Issue 11 • 2011

ISSN:2155-6199 n Citation: Varsha YM, Naga Deepthi CH, Chenna S (2011) An Emphasis on Xenobiotic Degradation in Environmental Clean up. J Bioremed Biodegrad S11:001. doi:10.4172/2155-6199.S11-001

Page 2 of 10

Paper and pulp residues Chemical and pharma wastes

Industrial residual wastes

Solid waste residues (dumps) Plastic wastes

Paint and dye eﬄuents

Figure 1: Different sources of Industrial Residual Wastes.

there was a need of bioplastics, a form of plastics derived from components are isolated from various environments, particularly renewable biomass sources, such as vegetable fats and oils, corn from petroleum-contaminated sites [16]. Saturated hydrocarbons starch, pea starch or micro biota, so that to degrade easily [14]. having the straight-chain (n-alkanes) are most susceptible to microbial attack than branched alkanes. The aromatic fraction Types of bioplastics include Starch-based plastics, Cellulose-based is more difficult to degrade and susceptibility of biodegradation plastics, Polylactic acid (PLA) plastics, Bio-derived polyethylene. decreases as the aromacity increases in the compound [17]. Biodegradation can be achieved by microbial treatment, oxidation disintegration process, using UV rays or by Phytoremediation. 4. Paints: Volatile organic compounds and additives like emulsifiers, Many combinations and trails in making these bioplastics have been texturizers in paint are considered harmful which can be degraded tried recently for fast degradation of these, one such implemented by different means like chemicals (water as solvent), hygroscopic is Oxo-biodegradable plastic. OBD plastic is polyolefin plastic stresses and microbial sources [18]. to which has been added very small (catalytic) amounts of metal 5. Dyes: Dye agglomeration is the major cause for the persistence salts. Polyolefin’s is relatively inert due to its hydrophobic chain of xenobiotics and their presence in aquatic bodies will affect and high molecular weight, so its degradation is quite very photosynthetic activity in aquatic life due to reduced light difficult [15]. As long as the polyolefins are attached oxygen (as in penetration even at low concentrations [19,20]. Number of a littered state), they catalyze the natural degradation process to industrial processes, such as textile industries, paper printing and speed it up so that the OBD plastic will degrade when subject to photography uses synthetic dyes extensively, which usually have environmental conditions. Once degraded, they can interact with complex aromatic molecular structures. Azodyes (Black B, Turq biological processes to produce water, carbon dioxide and biomass. Blue GN, Yellow HEM, Red HEFB and Navy HER), anthraquinone The process is shortened from hundreds of years to months for and phthalocyanine dyes are commonly used dyes in these industries degradation and thereafter biodegradation depends on the micro- [21]. The degradation of these dyes produces aromatic amines, organisms in the environment. which may be carcinogenic, and mutagenic. Microorganism (living 3. Hydrocarbons: Petroleum effluents mainly contain polycyclic or dead biomass) has ability, not only to decolorize dyes but also (polynuclear) aromatic hydrocarbons, saturated hydrocarbons detoxify it [22,23], by adsorption of dyes on microbial surfaces and nitrogen-sulphur-oxygen compounds. Degradation of such because of the presence of negatively charged ligands in cell wall compounds using physico-chemical treatments is cost effective and components. Microbial degradation and decolorization of dyes is an environment friendly and cost-competitive alternative to chemical may lead to further disturbances in the environment, thus giving decomposition processes [24]. importance to biotreatments, which had an impact on reduction of these recalcitrants. Microorganisms that biodegrade these 6. Pesticides and Insecticides: A large number of pesticides and

J Bioremediat Biodegrad, an open access journal Special Issue 11 • 2011 ISSN:2155-6199 Citation: Varsha YM, Naga Deepthi CH, Chenna S (2011) An Emphasis on Xenobiotic Degradation in Environmental Clean up. J Bioremed Biodegrad S11:001. doi:10.4172/2155-6199.S11-001

Page 3 of 10

insecticides like organophosphorous compounds, benzimidazoles, Xenobiotic Degradation methyl parathion and morpholine are widely used and has contributed to the pollution load due to its slow degradation [25]. Several methods like physico-chemical and biological methods Although a slow process, microbial degradation is considered a have been employed in the treatment or removal of xenobiotics. The boon in this case, since these halogenated aromatic compounds physico-chemical methods are costly and often produce undesirable adversely affect the environment and ecosystem both directly and products which are toxic, requiring further treatment steps [11]. indirectly. Such type of techniques often add fragmented elements which cannot be degraded easily and will make the environment still worse. To 7. Paper and Pulp effluents:Effluent release from paper mill industries overcome these problems, many other eco-friendly techniques have also contributes environmental pollution and cannot be neglected. been reported such as Bioremediation, phytoremediation etc. (Figure 2). Many of the chlorinated organic compounds randomly synthesized during pulp bleaching are reason for this. The situation can often Bioremediation be made worse if pulp mill effluents are released to oxygen-limited Microbial degradation of xenobiotics is one of the important way or depleted (anaerobic) waters. The increased public awareness and to remove the environmentally harmful compounds. The potential more restrictive laws against polluting processes has forced paper of microorganisms to metabolize xenobiotic compounds has been industries to minimize release of adsorbable organic halides and to recognized as an effective means of toxic and hazardous waste removal search technologies for cleaner productions [26]. Certain species of [11,36]. anaerobic bacteria can methylate chlorinated organic compounds which increases both the toxicity and lipophilicity of the compound Bioremediation can be defined as any process that uses to higher animals [27]. The toxic compounds from pulp and microorganisms or their enzymes to return the environment altered paper mill effluent are di-, tri-, tetra-, and pentachlorophenols, by contaminants to its original condition [37]. It can also be described tetrachloroguaiacols and tetrachlorocatechols [28]. as “a treatability technology that uses biological activity to reduce the concentration or toxicity of a pollutant [38]. Bioremediation process Indirect sources: Indirect sources of xenobiotics include NSAIDs, involves detoxification and mineralization, where the waste is converted pharmaceutical compounds, pesticide residues etc. into inorganic compounds such as carbon dioxide, water and methane Pharmaceutically active compounds, being an indirect source [39]. When compounds are persistent in the environment, their of xenobiotics are discharged directly by manufacturers of the biodegradation often proceeds through multiple steps utilizing different pharmaceuticals or effluents from hospitals which have performed enzyme systems or different microbial populations. Contaminated their biologically intended effect and are passed onto the environment wastewater, ground or surface waters, soils, sediments and air where in either their complete or a fragmented state. These mainly include there has been either accidental or intentional release of pollutants or hormones, anesthetics and antibiotics which bioaccumulate in an chemicals are the sites where bioremediation are employed [40,41]. organism and passed on the other through the common food chain [29]. Biomaterials developed from the synthetic polymers have the Microbial bioremediation: Taking the waste product of one process biocompatibility but their degradation into toxic substances in the and using it as fuel or food for another process is one way to get done body is a cause for concern [30]. Even though they are the indirect biodegradation; it makes intelligent use of resources decreasing sources, they cause adverse effect on the ecological cycle. the pollution and microbes does the same. They use these residual compounds as one of their substrate and grow on them, degrading or Pollution of aquatic and soil is a worldwide problem that can fragmenting them, which is highly valuable in case of bioremediation result in uptake and accumulation of toxic chemicals in food chains [42,43]. and also harm to the flora and fauna of affected habitats [31]. Studies of bioaccumulation characteristics of various ecosystem is essential Effective Microorganism (EM) is the consortia of valuable and for long term planning of industrial waste disposal in ecosystem [32]. naturally occurring microorganisms which secretes organic acids and Bioaccumulation of pesticides and biomagnification processes lead to enzymes for utilization and degradation of anthropogenic compounds toxic behavioral effect on animals and mankind. DDT, having a half life [44]. These days, microbes are collected from the waste water, residual of 10 years and BHC are chemicals used in pesticides accumulate in the sites and distillery sludges which are believed to have the resistance plant or in plant parts like fruits and vegetables [33]. against the hazardous compounds. This is particularly due to their Non Steroidal Anti-inflammatory Drugs (NSAIDs) are a large tolerance capacity even at the higher concentrations of xenobionts diverse chemical group of drugs used in humans and animals for the [45]. Heavy metals and toxic organic pollutants which are believed to treatment of inflammation, pain and fever (analgesic) [34]. Diclofenac have resistance towards some of the microbes can be degraded using use in animals has been reported to have led to a sharp decline in the these tolerant microbes [46]. Microbial consortium used in activated vulture population, 95% decline in 2003, 99.9% decline as of 2008 [35]. sludges and aerated lagoons are used recently for solid waste effluent Environmental Protection Agency (EPA) is in action to reduce the removal [47]. Biofilter technology is used to remove the hazardous bioaccumulation and biomagnifications of various such xenobiotics by chemicals and heavy metals from the effluents which contain these some genetic modifications and biodegradation strategies. microbes capable of utilizing the substrates rapidly due to its high surface to volume ratio and fixed cell nature [48,49]. The current study deals with importance of xenobiotic degradation giving preference to different types of remediation process like Microbial biodegradation is carried out by different organisms like Bacteria, Fungus, and Algae (Figure 3). • Microbial Remediation • Phytoremediation 1. Bacteria-Biotic actors in Xenobiotic degradation: The basic • Photoremediation sequence followed by bacteria for biodegradation of xenobiotics • Other techniques compounds are (Figure 4).

Page 4 of 10

Microbial Xenobiotic remediation techniques

Bacteria Mycoremediation Phycoremediation

Bioremediation Photoremediation Figure 3: Classification showing organisms involved in microbial remedi - tion.

Manipulation of Cellular uptake of Ring cleavage substrate by ring compounds formation Microbial ﬁssion Phytoremediation remediation

Figure 2: Classification showing di ferent Xenobiotic techniques. Conversion of Utilization of cleaved product into metabolites standard Bacteria which endure bio-fix, a wide range of xenobiotic chemicals metabolites

include aerobic, anaerobic, Methanotrophic, methanogenic bacteria, Figure 4: Figure showing steps followed by bacterial for biodegradation. cyanobacteria and Sphingomonads [50] (Figure 5). a) Aerobic bacteria: Pseudomonas, Escherichia, Sphingobium, Pan- doraea, Rhodococcus, Gordonia, Bacillus, Moraxella, Micrococcus. Aerobic b) Anaerobic bacteria: Pelatomaculum, Desulfotomaculum, Syntro- phobacter, Syntrophus, Desulphovibrio, Methanospirillum, Meth- anosaeta [51]. Other techniques Anaerobic c) Methanogenic bacteria and Methanotrophic bacteria: The process of degrading hydrocarbons resulting methane gas and carbon dioxide as end product is called Methanogenesis [52]. Methanotrophs use oxygen to oxidize methane into carbon dioxide. Methane monooxygenase, enzyme generated by methanotrophs to react with methane can degrade a wide variety of chlorinated hydrocarbons. Sphingomonads Methanogenic d) Cyanobacteria: Cyanobacterial consortia are generally used for degradation of oil derivatives. The use of cyanobacterial mats for bioremediation will avoid the costly use of organic and inorganic fertilizers and their maintenance at large scale can take an Cynobacteria advantage [53]. e) Sphingomonads: Sphingomonads have a high capacity Figure 5: Figure showing different Microbial species involved in biodegradation. to degrade wide range of xenobiotics, including synthetic polymers, aromatic compounds etc and due to its plasmid- borne mechanism. Many Sphingomonads contain large plasmids genetic engineering approaches specially for dehalogenation. These are termed as “Super Bugs” which contain special genes responsible for xenobiotics degradation which also help them to residing on their plasmids [55]. Many such efficient strategies adapt to new environment quickly. Sphingomonads show adverse are evolved to replace the less eco-friendly physicochemical effect on polyethylene glycol (PEG) and polyvinyl-alcohol (PVA) approaches. degradation [54]. Many different types of bacteria are used now a days for common f) New Technologies: Identification of gene responsible for specific effluent treatment which is tabulated as below (Table 1). compound degradation would be beneficial to develop the recombinant Genetically Modified Organisms (GMOs) for the • Pseudomonas sp. has been characterized for complete and partial bioremediation of complex waste. Such advancements will always mineralization of organophosphorous pesticides and fungicides, be a helping hand to already existing techniques. Sequential morpholine and methyl parathion. Pseudomonas sp. also aerobic - anaerobic treatments are implied to degrade some of involved in characteristic aromatic and aliphatic hydrocarbon compounds, which are now replaced by these biochemical and degradation of oils [25]. Pseudomonas pseudomallei is used for

Page 5 of 10

efficient removal of phenols from aqueous solutions. Hexavalent water-sediment interface, which contains microbial consortium. Chromium which is water soluable and toxic is converted in Evidences have been presented that these mats mainly contain to trivalent Chromium (less toxic) by Pseudomonas sp. [56]. phototrophic Cynobacteria which have capability to actively Pseudomonas fluorescens SM1 strain is reported to be a good degrade petroleum derivatives [64]. candidate for remediation of some heavy metals and phenolics • Staphylococcus can form biofilms, a self produced polymer in heavily polluted sites [57]. P. aeruginosa is used for the matrix. This property makes the organism unique, helping in reclamation of oil/metal contaminated soils by producing fragmenting the compounds [65]. surfactants and tolerate to certain heavy metals [58] and this strain is also used in decolorization and degradation of reactive • It has been reported that urease producing bacteria like Proteus dye Remazol Black B (RBB) [59]. mirabilis, Pseudomonas aeruginosa and Micrococcus luteus produces “Microbial Concrete”, novel metabolic byproduct of • Bacillus sp. have been characterized and documented for their biomineralization which can remediate and restore the building ability to degrade benzimidazole compounds [25]. structures [66]. • Azotobacter sp. as the biomatrix is used to remove the less toxic • Rhodococcus erythropolis in vertical rotating immobilized cell trivalent Cr through biosorption. reactor is used as biocatalyst to carry out biodesulfurization of • Thermophilic bacteria Anoxybacillus rupiensis isolated from crude oil [67]. the hot water springs of Unhavre situated in the western coast 1. Mycoremediation: The process of using fungi for bioremediation of of Maharashtra for its ability to degrade a local textile effluent contaminated soils (usually) is termed as mycoremediation, coined containing dyes [3]. Synthetic dye Reactive Black 5, from by Paul Stamets. Mycoremediation plays a pivotal role in breaking the wastewater was degraded upto 80% by a thermophilic down numerous toxic substances like petroleum hydrocarbons, Anoxybacillus pushchinoensis, Anoxibacillus kamchatkensis and polychlorinated biphenyls, heavy metals (by biosorption), phenolic Anoxibacillus flavithermus [3]. Azo dyes degradation generally derivatives, persistent pesticides etc. Fungi utilize some of these needs microbial consortia or combinations of anaerobic and hazardious compounds as the nutrient source and convert them to aerobic steps. This time consuming process is now replaced by simpler fragmented forms. Microalgae have a potential to be used using lactic acid bacteria which is efficient under both anaerobic as a substrate for the bioenergy production on a commercial scale. and aerobic conditions [60]. Different classifications can be explained under this like • Polyethylene used for manufacturing plastics are degraded by Brevibaccillus borstelensis and Rhodococcus ruber which • Ligninolytic fungal degradation • Fungal biosorption can degrade the CH2 backbone and use polyethylene as its sole carbon source due to the hydrophobic nature of the cell • Mycorrhizal fungal degradation membranes [61]. a) Ligninolytic fungal degradation: Many fungal species like basidiomycetes, ascomycetes have the potential to degrade • Microbial enhancing oil recovery processes (MEOR), uses lignocelluloses materials present in dead wood, paper and pulp biosurfactants which reduces the interfacial tension between effluents [68]. oil and water interfaces. Some gram positive, spore forming bacteria like Bacillus subtilis releases surfactin, a biosurfactant Basidiomycetes species are considered to be a very interesting group which acts up on oil spills and degrade them easily [62,63]. of fungi, considered as natural lignocellulose destroyers and include very different ecological groups such as white rot, brown rot, and • Microbial mats develop on the accidental oil spillages at the leaf litter fungi. Polycyclic aromatic hydrocarbons from natural oil deposits are degraded by laccases, a copper containing enzyme Xenobiotic compound Bacteria involved in Degradation found in these basidiomycetes [69]. White-rot fungi degrades PVC Cryptococcus elinovic under aerobic conditions secreting extracellular enzymes which act Bacillus sterothermophilus Burkholderia cepacia G4 on the polymers. An edible rot fungus, Pleurotus pulmonarius is Phenol Pseudomonas putida known for its ability to degrade crude oil [70]. Ligninolytic fungi Pseudomonas aeruginosa show higher potentials to degrade organ pollutants including Acinetobacter sp. Strain W-17 [11] Serratia marinorubra synthetic dyes. Nowadays immobilized fungal cultures in semisolid Bacillus sp. YW and YDLK consortia state-, trickling-bed- and rotating disk reactors are used for efficient Acinetobacter sp biodegradation of textile dyes, because of the advantages which Dyes (textile effluent Thermophilic Anoxybacillus pushchi- include long retention time of biomass in the system, ease of use noensis Anoxibacillus kamchatkensis in a continuous reactor and their ability for scale up [3]. Mascoma Anoxibacillus flavithermus demonstrated that Saccharomyces cerevisiae can convert 85% Pseudomonas A3 of paper sludge to ethanol without the addition of commercial Pseudomonas putida Pesticides and Fungicides enzymes. Trichoderma harzianum (also a fungicide) is well known P. aeruginosa Serratia marinorubra producer of cellulolytic enzymes that extensively used for the Brevibaccillus borstelensis degradation of cellulose in textile and paper industries [71]. Plastics Rhodococcus ruber Pseudomonas aeroginosa b) Biosorption by Fungi: Biosorption is a physiochemical process that occurs naturally in certain biomass (abundant (seaweed) or Table 1: Table showing different types of bacteria involved in xenobiotic degradation. wastes from other industrial operations) which allows it to passively

Page 6 of 10

concentrate and bind contaminants onto its cellular structure [72]. target the organic and inorganic pollutants in the water, soil and air Biosorption have an upper hand over bioaccumulation process simultaneously. since accumulated metal or waste can be desorbed easily by simple physical methods without damaging the biosorbent’s structural Plants have exposed the capacity to withstand relatively high integrity [73]. concentrations of organic xenobiotic chemicals without toxic effects [85] and also have capacity to take up and convert chemicals quickly Fungus is considered as most promising adsorbant, whose cell walls to less toxic metabolites [86]. Deep roots, luxuriant leaves have special and their components have a major role in biosorption. It has been sorptive properties and the associated bacteria in root zones allow reported that fungal biomass can also take up considerable quantities plants to absorb, take-up, accumulate, metabolize and/or degrade the of organic pollutants from aqueous solution by adsorption or a pollutants from water, soil and air. related process, even in the absence of physiological activity [74]. Phytoremediation can be classified in to subcategories depending Many fungal species such as Mucor sp, Aspergillus carbonaruius, up on the type of remediation (Figure 6). Aspergillus niger, Rhizopus sp, Saccharomyces cerevisiae, Botrytis cinerea, Neurospora crossa, Phanerochaete chrysosporium and 1. Rhizodegradation: Rhizodegradation is the enhancement of Lentinus sajor-caju have been extensively studied for heavy metal naturally-occurring biodegradation in soil through the influence of biosorption [75]. Saccharomyces cerevisiae was found to be the plant roots, and ideally will lead to destruction or detoxification of efficient biosorber of heavy metals like Pb, Au, Co, Cu [76]. an organic contaminant. A wide range of organic contaminants are candidates for rhizodegradation, such as petroleum hydrocarbons, Along with fungus, plant and its parts like solid residues of oil mill PAHs, pesticides, polychlorinated biphenyls (PCBs), surfactants products, sawdust, straw xanthate, aquatic plants and seaweeds also and chlorinated solvents. plays a pivotal role in adsorbing waste compounds. New techniques have been evolved which implement the fungal symbiont residing 2. Phytodegradation: Phytodegradation, also called as phytotransfor- in the plants where both fungal and plant part help in bioadsorption mation, is the uptake, metabolizing, and degradation of contami- [77]. nants within the plant, or the degradation of contaminants in the soil, sediments, sludges, ground water, or surface water by enzymes c) Mycorrhizal fungal degradation: Mycorrhiza, a symbiotic produced and released by the plant. The term “Green Liver Model” association of fungi and actinomycetes with the root zone of the is used to describe phytotransformation, as plants behave analo- vascular plant which increases soil organic carbon. Mycorrhizal gously to the human liver when dealing with these xenobiotic com- fungi, growing as a symbiont encourage degradation of organic pounds (foreign compound/pollutant). Chlorinated solvents like contaminants in soil. The typical mycorrhizons which naturally TCE, some organic herbicides and trinitrotoluene can be degraded biodegrade the organic pollutants are Morchella conica and using this method [87]. Tylospcno fibrilnsa [78]. 3. Phytoextraction: Phytoextraction (also known as phytoaccumu- d) Phycoremediation: Phycoremediation is defined as the use of lation, phytoabsorption, and phytosequestration) is contaminant macroalgae or microalgae to remove or biodegrade pollutants from uptake by roots with subsequent accumulation in the aboveground the environment. Algae possess the ability to take up toxic heavy portion of a plant, generally to be followed by harvest and ulti- metals from the environment, resulting in higher concentrations mate disposal of the plant biomass. Phytoextraction has also been than those in the surrounding water [79]. Special polysaccharides referred to as phytomining or biomining. Phytomining is the use are present in the algae cell wall contained potential metal ion of plants to obtain a gain from hyperaccumulated metals extracted binding sites. by a plant, whether from contaminated soils or from soils having Commonly used algal groups for degradation are Chlorococcum sp, naturally high concentrations of metals. This is particularly useful Chroococcus sp, Desmococcus sp, Dactylococcopsis sp, Chlamydo- for removing metals from soil and, in some cases; incorporation monas sp [80]. Blue Green Algae is extensively used for wastewater of plant incinerations will help metal reuse [87]. These processes treatment. Recent studies have quoted that, Spirulina platensis, a extract both metallic and organic constituents from soil by direct uptake into plants and translocation to aboveground biomass using photosynthethis blue-green algae is used as biosensor to detect the metal- (hyper) accumulating plants. Brassica juncea, Berkeya cod- mercury concentration accumulated in the solids waste residues dii, Allysum bertolonii, Thlaspi caerulescens and Thlaspi goesingense and soil. Biosorption using Blue Green Algae has distinct advan- are some of the plants involved in phytoextraction [88]. The main tages over the conventional methods because of reasons like advantage of phytoextraction is the process is eco- friendly but will • easy to operate take more time than anthropogenic soil clean-up methods. • cost effective for the treatment of large volumes of waste waters 4. Rhizofiltration: Rhizofiltration (also known as phytofiltration) • it could be selective is the removal by plant roots of contaminants in surface water, • More efficient [81]. waste water, or extracted ground water, through adsorption or Phytoremediation: Phytoremediation (also called as green precipitation onto the roots, or absorption into the roots. Here remediation, botano-remediation, agro remediation, and vegetative accumulation can occur in root or can be retained in any portion remediation) is method that use green or higher terrestrial plants of the plant. Plants used for rhizofiltration are not planted directly for treating chemically polluted soils [82], reducing the amount of in situ but are acclimated to the pollutant first, which makes the process little tedious and time consuming. Sunflowers grown in hazardous compounds [83]. USEPA (2000) defines phytoremediation radioactively contaminated pools exemplify this process. as “the use of plants for containment, degradation or extraction of xenobiotics from water or soil substrates” [84]. Using green plants as 5. Phytovolatilization: Phytovolatilization is the uptake of a water weapons, phytoremediation is one of most eco-friendly technique to soluble contaminant by a plant, and the subsequent release of a vol-

Page 7 of 10

Phytoremediation methods

Degradation Accumulation Dissipation Imobilization

Rhizodegradation Phytoextraction Phytovolatilization Phytohydraulics

Phytodegradation Rhizoﬁltration Phytostabilization

Figure 6: Phytoremediation techniques for xenobiotic degradation.

atile contaminant, a volatile degradation product of a contaminant, detoxify methyl mercury, a bioaccumulative organometalic cation, or a volatile form of an initially non-volatile contaminant. Plants as to the elemental mercury which can be volatilized by the plant [92]. phytovolatilizers have to be studied still for better utilization. 9. Pros and cons of phytoremediation: Phytoremediation is considered 6. Phytohydraulics (hydraulic plume control): Phytohydraulics is the a clean, cost-effective and non-environmentally disruptive technology, use of deep-rooted plants to degrade ground water contaminants as opposed to mechanical cleanup methods such as soil excavation that come into contact with their roots. Ground water plume of or pumping polluted groundwater [96]. Over the past 20 years, this methyl-tert-butyl-ether (MTBE) has been recovered using this technology progressed and has been employed at sites with soils technique [89]. contaminated with arsenic, lead and uranium. On the other hand, one major disadvantage of phytoremediation is that it requires 7. Phytostabilization: Phytostabilization (also called as phytoimmo- a long-term commitment, as the process is dependent on plant bilization) is the use of plants to immobilize soil and water con- growth, bioaccumulation capacity and tolerance to toxicity. taminants. Some organic contaminants or metabolic byproducts of these contaminants can be attached or incorporated into plant com- Although phytoremediation is a promising technique to remove ponents such as lignin and such type of phytostabilization is called pollutants, it is still an immature and developing technology to deal phytolignification [90]. Indian mustard appeared to have potential with pollution problems. However, it is clear that phytoremediation for phytostabilization. already plays an important role in removing pollutants from the environment we just need to find the right plant for the right 8. Recent trends used in phytoremediation: A recent strategy to pollutant [97]. improve phytoremediation and detoxification of contaminants is the use of endophytic bacteria which are often found genera in soil Photodegradation like Pseudomonas, Burkholderia, Bacillus, and Azospirillum [91]. Photodegradation is degradation of a molecule which has capability Genetic modification offers a new hope for phytoremediation to absorb photons, particularly those wavelengths found in sunlight, such as infrared radiation, visible light, and ultraviolet light. The as they can be used to over express the enzymes involved in the solution of plastic ecological problem is achieved by this particularly, existing plant metabolic pathways or to introduce new pathways due to the development of photodegradable and biodegradable polymer into plants [91,92]. With increased understanding of the enzymatic with controlled lifetime. Many new strategies have been introduced in processes involved in plant tolerance and metabolism of xenobiotic order to make this technique applicable for wide range of xenobiotic chemicals, there is new potential for engineering plants with degradation. Transition metals like Cr, Mn, Fe, Co act as antioxidant increased phytoremediation capabilities [93,94]. Transgenic plants or bioactive elements in photodegradation of polymer degradation that over express mercury-resistance genes have been reported to be [98]. Congo red dye used in the cellulose industries (cotton textile, highly resistant to organic mercury and are effective for degradation, wood pulp & paper) has long been abandoned, primarily because of its thus bringing a new advancement in the phytodegradation process tendency to change color and its toxicity. Recent advances to degrade [95]. this Congo red include photocatalytic degradation using ZnO/ UV-A Richard Meagher introduced a new pathway into Arabidopsis to [99,100].

Page 8 of 10

Initiators like Ketones, quinones and peroxides are added in Influence of microbial adaptation on the fate of organic pollutants in ground some cases to carry out photo-degradation reactions. Nowadays water. Environ Toxicol Chem 4: 721-726. photodegraded films are used to evaluate biodegradation using 8. Gayathri KV, Vasudevan N (2010) Enrichment of Phenol Degrading Moderately microorganisms such as Aspergillus niger and Pencillium funculosum Halophilic Bacterial Consortium from Saline Environment. J Bioremed Biodegrad 1: 104. for degradation of both natural and synthetic plastics. Heterotrophic microorganisms uses polymers especially plastics are potential 9. Jame SA, Rashidul Alam AKM, Fakhruddin ANM, Alam MK (2010) Degradation substrates and degrade them first converting them to simpler of Phenol by Mixed Culture of Locally Isolated Pseudomonas Species. J Bioremed Biodegrad 1: 102. monomeric forms [101]. 10. Nagamani B, Chandana Lakshmi MVV, Sridevi V (2011) Enhanced Although many such techniques are implied to reduce these biodegradation of phenol by Pseudomonas pseudomallei with additional xenobiont in the environment, each one have their own drawback. carbon sources. World Congress of Biotechnology, India. Biodegradation actually means complete elimination, but this is not the 11. Sridevi V, Lakshmi MVVC, Swamy AVN, Rao MN (2011) Implementation of case in most of the above process. Fragmental release due to these steps response surface methodology for phenol degradation using Pseudomonas also effect the environ in the long run. Eco-Industrial Parks (EIP) have putida (NCIM 2102). J Bioremed Biodegrad 2: 121. been built which is actually an association between local community 12. Sylvia Katz (1995) Degradation of Polymers. 377-378. and business corporate to solve the environmental problems. The 13. Krishnamoorthy R (2010) Plastic waste to be used in cement units. benefits Eco-Industrial Parks may serve as incentives for companies to improve their environmental performance in terms of management of 14. http://en.wikipedia.org/wiki/Bioplastic hazardous waste, raw materials, conservation of energy use. The EIP 15. Santhoskumar AU, Palanivelu K, Sharma SK, Nayak SK (2010) A New prevent further degradation of our environment and remediate damage Synthesis of Nickel 12-Hydroxy Oleate Formulation to Improve Polyolefi n’s caused by increasingly industrialized society via phytotechnologies. Degradation. J Bioremed Biodegrad 1: 108. Such EIP offer efficient and environmentally friendly solutions to clean 16. Whyte LG, Bourbonnière L, Greer CW (1997) Biodegradation of petroleum up contaminated soils, sediments, brown fields and wastewater, to hydrocarbons by psychrotrophic Pseudomonas strains possessing both a Alkane (alk) and naphthalene (nah) catabolic pathways. Appl Environ Microbiol enhance food chain safety and to develop renewable energy sources [102]. 63: 3719-3723.

Conclusion 17. Mirdamadian SH, Emtiazi G, Golabi MH, Ghanavati H (2010) Biodegradation of Petroleum and Aromatic Hydrocarbons by Bacteria Isolated from Petroleum- Environmental problems caused by the industrial effluents is mainly Contaminated Soil. J Pet Environ Biotechnol 1: 102. due to accumulation of pollutants and other fragmented compounds, 18. Senalee Kapelevich (2011) Paint: Conventional Vs Non Toxic. Ezine Articles. which in turn form into other substitutes (natural or manmade), finally forming a xenobiont. There is a quick need to degrade these 19. Abdelkader E, Nadjia L, Ahmed B (2011) Degradation Study of Phenazin Neutral Red from Aqueous Suspension by Paper Sludge. J Chem Eng Process xenobiotic compounds in an eco-friendly way. Various techniques Technol 2: 109. like microbial remediation, phytoremediation and photoremediation 20. Elaziouti A, Laouedj N, Ahmed B (2011) Effect of pH Solution on the Optical and their subtypes have been discussed. Each having their own ways Properties of Cationic Dyes in Dye/ Maghnia Montmorillonite Suspensions. J of degrading these xenobionts, also have negative impact on the Chem Eng Process Technol 2: 113. environ (side effects due to fragmentations and bioaccumulations). 21. Acuner E, Dilek FB (2004) Treatment of Tectilon Yellow 2G by Chlorella Photoremediation, a novel equipment based technique which is rapid vulgaris. Process Biochem 39: 623-631. but also have a negative impact on the environment. Being a solar driven 22. Rajaguru P, Kalaiselvi K, Palanivel M, Subburam V (2000) Biodegradation of technique, phytoremediation is restricted to particular sites containing azo dyes in a sequential anaerobic–aerobic system. Appl Microbiol Biotechnol contaminants. Although slow, on the whole microbial bioremediation 54: 268-273. was found to cover wide range of recalcitrant degradation and is known 23. Adedayo O, Javadpour S, Taylor C, Anderson WA, Moo-Young M (2004) to be a better choice because of its nature of degradation. Decolorization and detoxifi cation of methyl red by aerobic bacteria from a wastewater treatment plant. World J Microbiol Biotechnol 20: 545-550.

References 24. Ramya M, Iyappan S,ManjuA, Jiffe JS (2010) Biodegradation and Decolorization of Acid Red by Acinetobacter radioresistens. J Bioremed Biodegrad 1: 105. 1. Vidali M (2001) Bioremediation. An overview. Pure Appl Chem 73: 1163-1172. 25. Lalithakumari D (2011) MICROBES: “A TRIBUTE” TO CLEAN ENVIRONMENT. 2. Sethy NK, Jha VN, Sahoo SK, Shukla AK, Tripathi RM, et al. (2011) Ground Water Ingestion Dose Due to Intake of Radionuclide (Natural U and 226Ra) to 26. Shalini Singh, Dharm Dutt, Tyagi CH, Seema Singh Vidyarthi AK (2011) Efficacy Population Around Uranium Mining Complex at Jaduguda. J Ecosys Ecograph of a novel crude cellulose-poor xylanase from Coprinellus disseminatus SH-1 1: 104. NTCC1163 to mitigate AOX in combined effluent generated during conventional and ECF bleaching. World Congress of Biotechnology. 3. Gursahani YH, Gupta SG (2011) Decolourization Of Textile Effluent by A Thermophilic Bacteria Anoxybacillus rupiensis. J Pet Environ Biotechnol 2: 111. 27. Murray, William (1992) PULP AND PAPER: THE REDUCTION OF TOXIC EFFLUENTS. Environment Canada, Science and Technology Division. 4. Sharma SK, Saxena M, Mandal TK, Ahammed YN, Pathak H, et al. (2011) Variations in Mixing Ratios of Ambient Ammonia, Nitric Oxide and Nitrogen 28. Tana, JJ (1988) Sublethal Effects of Chlorinated Phenols and Resin Acids on Dioxide in Different Environments of India. J Food Process Technol 1: 101. Rainbow Trout (Salmo gairdneri). Water Sci Technol 20: 77-85.

5. le Mellec A, Karg J, Bernacki Z, Slowik J, Korczynski I, et al. (2010) Effects of 29. Heberer (2002) Occurrence, Fate and Removal of Pharmaceutical Residues in The Aquatic Environment- A Review of Recent Research Data. Toxicol Lett Insect Mass Outbreaks on Throughfall Composition in Even Aged European 131: 5-17. Pine Stands - Implications for the C and N Cycling. J Earth Sci Climat Change 1: 101. 30. Reddy N, Yang Y (2011) Plant Proteins for Medical Applications. J Microbial Biochem Technol 3: i-i. 6. Indu Shekhar Thakur (2006) Xenobiotics: Pollutants and their degradation- methane, benzene, pesticides, bioabsorption of metals. 31. Fayidh MA, Babuskin S, Sabina K, Sukumar M, Sivarajan M (2011) Integrated Approach to the Problems of Dye Wastewater by Sonolysis and Biological 7. Wilson JT, McNabb JF, Cochran JW, Wang TH, Tomson MB, et al. (1985) Treatment. J Microbial Biochem Technol 3: 060-066.

Page 9 of 10

32. Sethy NK, Jha VN, Shukla AK, Sahoo SK, Tripathi RM, et al. (2011) Natural 53. Raeid MMA (2011) Unraveling the role of cyanobacterial mats in the cleanup of Radionuclide (U and 226Ra) in Water, Sediment, Fish and Plant Species in oil pollutants using modern molecular and microsensor tools. World Congress the Aquatic Environment around Uranium Mining and Ore processing Site at on Biotechnology, India. Jaduguda, India. J Ecosys Ecograph 1: 103. 54. Xenobiotic polymer-degradation by Sphingomonads. 33. Karanth NGK (2000) Challenges of Limiting Pesticide Residues in Fresh 55. Kensuke Furukawa (2003) ‘Super bugs’ for bioremediation. Trends Biotechnol Vegetables: The Indian Experience Food Safety Management in Developing 21: 187-189. Countries. CIRAD-FAO 11-13 56. Poornima K, Karthik L, Swadhini SP, Mythili S, Sathiavelu A (2010) Degradation 34. Monadjem, M.D. Anderson, S.E. Piper & A.F. Boshoff (2004) The Vultures of of Chromium by Using a Novel Strains of Pseudomonas Species. J Microbial Southern Africa – Quo Vadis? Biochem Technol 2: 095-099.

35. Oaks JL, Gilbert M, Virani MZ, Watson RT, Meteyer CU, et al. (2004) Diclofenac 57. Wasi S, Tabrez S, Ahmad M (2010) Isolation and Characterization of a Residues as the Cause of Vulture Population Decline in Pakistan. Nature 427: Pseudomonas fl uorescens Strain Tolerant to Major Indian Water Pollutants. J 630–633. Bioremed Biodegrad 1: 101.

36. Agarry SE, Durojaiye AO, Yusuf RO, Aremu MO, Solomon BO, et al. (2008) 58. Mathiyazhagan N, Natarajan D (2011) Bioremediation on effluents from Biodegradation of Phenol in Refinery Wastewater by Pure Cultures of Magnesite and Bauxite mines using Thiobacillus Spp and Pseudomonas Spp. Pseudomonas aeruginosa NCIB 950 And Pseudomonas fluorescenc NCIB J Bioremed Biodegrad 2: 115. 3756. Int J Environ Poll 32: 3-11. 59. Joe J, Kothari RK, Raval CM, Kothari CR, Akbari VG, et al. (2011) Decolorization 37. Boopathy R (2000) Factors limiting bioremediation technologies. Biores of Textile Dye Remazol Black B by Pseudomonas aeruginosa CR- 25 Isolated Technol 74: 63-67. from the Common Effluent Treatment Plant. J Bioremed Biodegrad 2: 118.

38. King RB, Long GM, Sheldon JK (1997) Practical Environmental Bioremediation: 60. Elbanna K, Hassan G, Khider M, Mandour R (2010) Safe Biodegradation the Field Guide, 2nd ed., Lewis, Boca Raton, FL. of Textile Azo Dyes by Newly Isolated Lactic Acid Bacteria and Detection of Plasmids Associated With Degradation. J Bioremed Biodegrad 1: 110. 39. Reshma SV, Spandana S, Sowmya M (2011) Bioremediation Technologies. World Congress of Biotechnology, India. 61. Hadad D, Geresh S, Sivan A (2005) Biodegradation of polyethylene by the thermophilic bacterium Brevibacillus borstelensis. Journal of Applied 40. Ali Elredaisy SM (2010) Ecological Benefits of Bioremediation of Oil Microbiology 98: 1093-1100. Contaminated Water in Rich Savannah of Palogue, Upper Nile Area-Southern Sudan. J Bioremed Biodegrad 1: 103. 62. Amin GA (2010) A Potent Biosurfactant Producing Bacterial Strain for Application in Enhanced Oil Recovery Applications. J Pet Environ Biotechnol 41. Aghamiri SF, Kabiri K, Emtiazi G (2011) A Novel Approach for Optimization 1: 104. of Crude Oil Bioremediation in Soil by the Taguchi Method. J Pet Environ Biotechnol 2: 108. 63. Owolabi RU, Osiyemi NA, Amosa MK, Ojewumi ME (2011) Biodiesel from Household/Restaurant Waste Cooking Oil (WCO). J Chem Eng Process 42. Iyovo GD, Du G, Chen J (2010) Sustainable Bioenergy Bioprocessing: Technol 2: 112. Biomethane Production, Digestate as Biofertilizer and as Supplemental Feed 64. Bordenave S, Goni-Urriza M, Caumette P, Duran R (2009) Differential Display in Algae Cultivation to Promote Algae Biofuel Commercialization. J Microbial Analysis of cDNA Involved in Microbial Mats Response after Heavy Fuel Oil Biochem Technol 2: 100-106. Contamination. J Microbial Biochem Technol 1: 001-004. 43. Surani JJ, Akbari VG, Purohit MK, Singh SP (2011) Pahbase, a Freely Available 65. Schillaci D (2011) Staphylococcal Biofilms: Challenges in the Discovery of Functional Database of Polycyclic Aromatic Hydrocarbons (Pahs) Degrading Novel Anti-infective Agents. J Microbial Biochem Technol 3: iv-vi. Bacteria. J Bioremed Biodegrad 2: 116. 66. Reddy MS, Achal V, Mukherjee A (2011) Microbial concrete a wonder metabolic 44. Monica S, Karthik L, Mythili S, Sathiavelu A (2011) Formulation of Effective product improves durability of building structures. World Congress on Microbial Consortia and its Application for Sewage Treatment. J Microbial Biotechnology, India. Biochem Technol 3: 051-055. 67. Amin GA (2011) Integrated Two-Stage Process for Biodesulfurization of 45. Narasimhulu K, Rao PS, Vinod AV (2010) Isolation and Identification of Model Oil by Vertical Rotating Immobilized Cell Reactor with the Bacterium Bacterial Strains and Study of their Resistance to Heavy Metals and Antibiotics. Rhodococcus erythropolis. J Pet Environ Biotechnol 2: 107. J Microbial Biochem Technol 2: 074-076. 68. Kenneth E. HAMMEL (1996) Extracellular Free Radical Biochemistry of 46. Tripathi BD (2011) A Short Term Study on Toxic Effects of Distillery Sludge Ligninolytic Fungi. New J Chem 20: 195-198. Amendment on Microbiological and Enzymatic Properties of Agricultural Soil in a Tropical City. J Earth Sci Climat Change 1: 106. 69. Cho NS, Wilkolazka AJ, Staszczak M, Cho HY, Ohga S (2009) The role of laccase from white rot fungi to stress conditions. J Fac Agric Kyushu Univ 54: 47. Priya PG, Ramamurthi V, Anand P (2011) Degradation Studies of Tannery 81-83. Effluents using Electro Flotation Technique. J Chem Eng Process Technol 2: 104. 70. Olusola SA, Anslem EE (2010) Bioremediation of a Crude Oil Polluted Soil with Pleurotus Pulmonarius and Glomus Mosseae Using Amaranthus Hybridus as a 48. Rodrigues DF (2011) Biofilters: A Solution for Heavy Metals Removal from Test Plant. J Bioremed Biodegrad 1: 111. Water? J Bioremed Biodegrad 2: e101. 71. El-Bondkly AM, Aboshosha AAM, Radwan NH, Dora SA (2010) Successive 49. Djefal-Kerrar A, Ouallouche-Abdoun K, Chouikrat R, El-Kahina YG, Nacer- Construction of ß-Glucosidase Hyperproducers of Trichoderma Harzianum Khodja A, et al. (2011) Study of Bacterium Fixation Stability on Gamma Using Microbial Biotechnology Techniques. J Microbial Biochem Technol 2: Radiation Synthesized Carriers to Improve Degradation. J Bioremed Biodegrad 070-073. 2: 117. 72. http://en.wikipedia.org/wiki/Biosorption 50. Sinha S, Chattopadhyay P, Pan I, Chatterjee S, Chanda P, et al. (2009) 73. Gurel L, senturk I, Bahadir T, Buyukgungor H (2010) Treatment of Nickel Plating Microbial transformation of xenobiotics for environmental bioremediation. Afr Industrial Wastewater by Fungus Immobilized onto Rice Bran. J Microbial J Biotechnol 8: 6016-6027. Biochem Technol 2: 034-037.

51. Chowdhury S, Mishra M, Adarsh VK, Mukherjee A, Thakur AR, et al. (2008) 74. Kurnaz SU, Buyukgungor H (2009) Assessment of Various Biomasses in the Novel metal accumulator and protease secretor microbes from East Calcutta Removal of Phenol from Aqueous Solutions. J Microbial Biochem Technol 1: Wetland. Am J Biochem Biotechnol 4: 255-264. 047-050.

52. Jha AK, Singh K, Sharma C, Singh SK, Gupta PK (2011) Assessment of 75. Kumar KK, Prasad MK, Sarma GVS, Murthy CVR (2009) Removal of Cd (II) Methane and Nitrous Oxide Emissions from Livestock in India. J Earth Sci from Aqueous Solution Using Immobilized Rhizomucor Tauricus. J Microbial Climat Change 1: 107. Biochem Technol 1: 015-021.

Page 10 of 10

76. Rajesh D, Anju H, Radha S, Poonam AS (2011) Saccharomyces cerevisiae: 89. Pilon-Smits EAH, de Souza MP, Hong G, Amini A, Bravo RC et al. (1999) A Potential Biosorbent for Biosorption of Uranium. International Journal of Selenium volatilization and accumulation by twenty aquatic plant species. J Engineering Science And Technology 3: 5397- 5407. http://www.ijest.info/docs/ Environ Qual 28: 1011-1017 IJEST11-03-06-212.pdf 90. Saharan BS, Nehra V (2011) Plant Growth Promoting Rhizobacteria: A Critical 77. Kumar NK, Reddy DSR, Venkateswarlu P (2010) Application of Response Review. Life Sciences and Medicine Research 2011: LSMR-21. Surface Methodology for Optimization of Chromium Biosorption from an Aqueous Solution onto Syzigium cumini (java) Seed Powder. J Microbial 91. Ram SV, Srivastava PN (2008) Phytoremediation- Green for Environmental Biochem Technol 2: 020-027. Clean. The 12th World Lake Conferance: 1016-102 India.

78. Bennet JW, Wunch KG, Faison BD (2002) Use of Fungi Biodegradation Manual 92. http://arabidopsis.info/students/dom/mainpage.html of Environmental Microbiology ASM Press Washington DC. 93. Jaanis Juhanson (2010) Impact of Phytoremediation and Bioaugmentation on 79. Imamul Huq SM, Abdullah MB, Joardar JC (2007) Bioremediation of arsenic the Microbial Community in Oil Shale Chemical Industry Solid Waste. Tarutu toxicity by algae in rice culture. Land Contamination & Reclamation 15: 327- University Press. 334. 94. Annette CD, Jerald LS (2001) Advances in Phytoremediation. Environ Health 80. Sivasubramanian V, Subramanian VV, Muthukumaran M (2010) Bioremediation Perspect 109: 163-168. of Chrome-Sludge from an Electroplating Industry Using the Micro Alga Desmococcus olivaceus – A pilot study. J. Algal Biomass Utln. 3: 104-128. 95. Sonoki T, Kajita S, Uesugi M, Katayama Y, Iimura Y (2011) Effective Removal of Bisphenol a from Contaminated Areas by Recombinant Plant Producing Lignin 81. Parameswari E, Lakshmanan A, Thilagavathi T (2010) Phycoremediation of Peroxidase. J Pet Environ Biotechnol 2: 105. Heavy Metals in Polluted Water Bodies. Elec J Env Agricult Food 9: 808-814. 96. Wei SH, Zhou QX, Wang X, Cao W, Ren LP, et al. (2004) Potential of Weed 82. Wenzel WW, Lombi E, Adriano D (1999) Biogeochemical Processes in the Species Applied to Remediation of Soils Contaminated With Heavy Metals. J Rhizosphere: Role in Phytoremediation of Metal-Polluted Soils. In Heavy metal Environ Sci 16: 868-873. stress in plants - from molecules to ecosystems. Springer Verlag 273-303. 97. Zhai G (2011) Phytoremediation: Right Plants for Right Pollutants. J Bioremed 83. Maria NDSU, Walter WW (2006) Phytoextraction of Metal Polluted Soils in Latin Biodegrad 2: 102e. America. Environmental Applications of Poplar and Willow Working Party. 98. Zhang B, Shahbazi A (2011) Recent Developments in Pretreatment Technologies 84. Lorestani B, Cheraghi M, Yousefi N (2011) Phytoremediation Potential of Native for Production of Lignocellulosic Biofuels. J Pet Environ Biotechnol 2: 108. Plants Growing on a Heavy Metals Contaminated Soil of Copper mine in Iran. World Acad Sci Eng Techno 77: 377-382. 99. Elaziouti, Laouedj N, Ahmed B (2011) ZnO-Assisted Photocatalytic Degradation of Congo Red and Benzopurpurine 4B in Aqueous Solution. J Chem Eng 85. Briggs GG, Bromilow RH, Evans AA (1982) Relationships between lipophilicity Process Technol 2: 106. and root uptake and translocation of non-ionised chemicals by barley. Pestic Sci 13: 495-504. 100. Santhoskumar AU, Palanivelu K, Sharma SK, Nayak SK (2010) Comparison 86. Kolb M, Harms H (2002) Metabolism of Fluoranthene in Different Plant Cell of Biological Activity Transistion Metal 12 Hydroxy oleate on Photodegradation Cultures and Intact Plants. Environ Toxicol Chem. 19: 1304-1310. of Plastics. J Bioremed Biodegrad 1: 109.

87. Shukla KP, Singh NK, Sharma S (2010) Bioremediation: Developments, 101. Nadjia L, Abdelkader E, Ahmed B (2011) Photodegradation study of Congo Current Practices and Perspectives. Genetic Engineering and Biotechnology Red in Aqueous Solution using ZnO/UV-A: Effect of pH And Band Gap of Journal 3: 1-20. other Semiconductor Groups. J Chem Eng Process Technol 2: 108.

88. Bruce EP (2001) Phytoremediation of Contaminated Soil and Ground Water at 102. Prasad MNV (2011) Eco-Industrial parks for pollution abatement and Hazardous Waste Sites. remediation World Congress on Biotechnology, India.

J Bioremediat Biodegrad, an open access journal Special Issue 11 • 2011 ISSN:2155-6199