Research Journal of Chemical and Environmental Sciences Res J. Chem. Environ. Sci. Vol 2 [3] June 2014: 05-16 Online ISSN 2321-1040 CODEN: RJCEA2 [USA] RJCES ©Academy for Environment and Life Sciences, INDIA REVIEW ARTICLE Actinomycetes: Potential Bioresource for Human Welfare: A Review 1Roshan Kumar*, 2Koushik Biswas, 3Vikas Soalnki, 4Pankaj Kumar, 5Avijit Tarafdar 1School of Biotechnology, Chemical and Biomedical Engineering (SBCBE), VIT University, Vellore, (India) 2Department of Agricultural Biotechnology, CSK Himachal Pradesh Agricultural University, Palampur, Himachal Pradesh (India) 3Department of Biotechnology, Beehive College of Advance Studies, Selaqui, Dehradun (India) 4Department of Agricultural Biotechnology, CSK Himachal Pradesh Agricultural University, Palampur, HP (India) 5Cytogenetics and Tissue Culture Unit, Department of Botany,University of Kalyani, Nadia, West Bengal (India) Corresponding Author- [email protected] ABSTRACT Microbial natural products are the origin of most of the antibiotics in the market today. There is an alarming scarcity of new antibiotics currently under development in the pharmaceutical industry. Still, microbial natural products remain the most promising source of novel antibiotics, although new approaches are required to improve the efficiency of the discovery process. Actinomycetes which are the prolific producers of antibi-otics and important suppliers to the pharmaceutical and other industry they are well known for their ability to produce secondary metabolites many of which are active against pathogenic microorganisms. It is only more recently that actinomycetes have become recognized as a source of novel antibiotics and anticancer agents with unusual structures and properties. They are a promising source of wide range of important enzymes, some of which are produced on an industrial scale, but many other remained to be harnessed. The application of enzymes in diverse biotechnological industries indicates a positive trend which needs to be satisfied with the discovery of novel enzymes and metabolites. Since very few enzymes have been potentially utilize data the industrial level; there is a huge scope for the development of robust and low cost enzymes. Actinomycetes are a reservoir of important enzymes and metabolites due to their versatile genetic repertory. They perform microbial transformations of organic compounds, a field of great commercial value. Members of many genera of actinomycetes have potential for use in the bioconversion of underutilized agricultural and urban wastes into high-value chemical products. Keywords- Actinomycetes, bioactive compound, Antibiotics, Enzymes. Received 12.03.2014 Accepted 13.05.2014 © 2014 AELS, INDIA INTRODUCTION Actinomycetes are a wealthy source for the synthesis of medically and technically useful natural products. From the ancient times actinomycetes is mostly related to its use as an antibiotic. Its use as an anti fungal agent in the past is mostly responsible for its popularity with antibiotic research today. From 1914 to 1939, Selman A. Waksman had been systematically screening soil bacteria and fungi in an attempt to find an antibiotic for Tuberculosis. University of California (1939) discovered the effect of certain fungi, especially antinomycetes, on bacterial growth. Actinomycetes slowed bacterial growth because of the antibiotics they produce.Actinomycetes comprise a substantially larger group having wider range of applications in food and pharma. Actinomycetes are Gram-positive bacteria with a high G+C (>55%) content. Among others, representative genera include Micrococcus, Mycobacterium, Nocardia, Propionibacterium, and Streptomyces. Many actinomycetes, such as Streptomyces, grow as branching filaments and live in soil, as fungi do. Because of this resemblance, actinomycetes were originally classified as fungi. This was reflected on their name, where "mycetes" comes from the Greek for "mushroom, fungus". The actinomycetes represent a ubiquitous group of microbes that are widely distributed in natural ecosystems around the world and are particularly significant for their role in the recycling of organic matter. [1, 2] reported a bimodal distribution of actinomycetes in near shore tropical marine environments. The habitat of actinomycetes corresponds to its behavioral characteristics. Actinomycetes is a saprophyte, another word for a decomposing organism, which means it grows best in moist moderate to tropical atmospheres. This bacterium is also a heterotroph, meaning it draws its RJCES Vol 2 [3] June 2014 5 | P a g e © 2014 AELS, INDIA Kumar et al energy from surrounding sources such as dead and decomposing animal matter. These factors determine the habitat of actinomycetes. As a decomposer, actinomycetes is commonly found in compost piles and forest floor litter, and forms symbiotic relationships with red alders, a type of tree that forms anaerobic nodules in which actinomycetes fixes nitrogen for the tree. Actinomycetes bacteria are found in human and cattle bodies in the mouth, throat, and intestinal tract. Occurrence Actinomycetes occur in the soil in the spore stage as well as in the mycelial stage. As a result of comparative examination of the relative abundance of actinomycetes in the form of substrate growth and spores in soil, using the microscopic and plate methods. The mycelium developed most abundantly at 28 oC to 37 oC; at lower and higher temperatures growth was slower but eventually reached the same density. At higher temperatures, the mycelium underwent increasing fragmentation, giving rise to abundant formation of spores. Sporulation is also favored by a dry atmosphere. Enrichment of soil with bacteria leads to extensive actinomycete development; their excessive growth is due largely to the introduction of fresh supply of available nutrients in the form of bacterial cells. Addition of organic matter has in general a marked stimulating effect upon the development of Actinomycetes. When soils rich in organic matter such as peat bogs, are drained and aerated, actinomycetes are able to make extensive growth. Actinomycetes, including Streptomycetes and certain nocardiae, occur abundantly in and around the root systems of higher plants. (Table.1) contain list of actinomycetes strain present in particular plant and their function are given in. Some forms produce yellowish, orange, or black pigments in organic media. Some are spiral producing, others forming straight aerial mycelium. Certain horizons of different soil types were found to contain characteristic communities of Streptomycetes.Freshwater lakes, rivers, and sewage contain an abundance of actinomycetes, including thermophilic forms growing well at 60 oC. Diversity of marine actinobacteria An intriguing picture of the diversity of marine actinobacteria is beginning to emerge. Once largely considered to originate from dormant spores that washed in from land [3], it is now clear that specific populations of marine adapted actinobacteria not only exist but add significant new diversity within a broad range of actinobacterial taxa [ 4,5]. The first report on the marine actinobacteria was made by [6], when he observed and documented those in the salt mud. In 1969, Weyland [7] carried out an extensive survey on the distribution on marine actinobacteria in the sediments of North Sea and Atlantic Ocean and suggested that the marine actinobacteria are the best sources for isolation of unique bioactive compounds compared to terrestrial ones. After this, a number of researchers around the world have concentrated to isolate and identify the actinobacteria from the different marine habitats. Ecology of antibiotic producing actinomycetes Microbial diversity is a substantial leading edge and prospective goldmine for biotechnology industry because it offers countless of secondary metabolites to probe for enzymes, antibiotics, antioxidant, cytotoxic and so many other useful substances [8-10]. The actinomycetes occur in vast diversity of habitat either natural or artificial, growing on different kinds of substrate. The diversity of actinomycetes is of exceptional impact in several areas of pharmaceutical, medicine and agriculture, particularly, in antibiotic production [11]. Actinomycetes are ubiquitous and have been isolated from various locations, in the soil, fresh water, marine, hot spring, mining sites, and also in extreme environments. Table 1. Examples of rizosphere some actinomycetes and their functions to plants. Rhizospheric Function Plant species References actinomycetes Micromonospora endolithica Phosphate solubilization to Bean (Phaseolus vulgaris [12] promote plant growth L.) Streptomyces griseus Protection against damping Wheat (Triticum spp.) [13] off disease caused by Pythium ultimum Frankia species Biological fixation of Actinorhizal plant [14] nitrogen (Casuarina equisetifolia) Norcardia levis Biological control of Sorghum (Sorghum bicolor) [15] Fusarium oxysporum wilt disease Streptomyces species Act as biocontrol against Tomato (Solanum [16] Rhizoctonia solani lycopersicum) Streptomyces species Bioremediation of Maize (Zea mays) [17] contaminated soil RJCES Vol 2 [3] June 2014 6 | P a g e © 2014 AELS, INDIA Kumar et al Role of actinomycetes in the marine environment The marine environment is characterized by the hostile parameters such as high pressure, salinity; low temperature, absence of light, etc. and the marine actinobacteria have adapted themselves to survive in this environment. They require Na+ for growth because it is essential