Int. J. Pharm. Sci. Rev. Res., 25(1), Mar – Apr 2014; Article No. 28, Pages: 165-170 ISSN 0976 – 044X International Journal of Pharmaceutical Sciences Review and Research Available online at www.globalresearchonline.net 165 Kalyani A.L.T*, Naga Sireesha G, Girija Sankar G, Prabhakar T AU College of Pharmaceutical Sciences, Pharmaceutical Biotechnology Division, Andhra University, Visakhapatnam, India. *Corresponding author’s E-mail: kalyani.lakshmitripura@gmail.com Accepted on: 31-12-2013; Finalized on: 28-02-2014. ABSTRACT This is a study of the crude bio-surfactant produced by a Streptomyces matensis PLS-1 isolate from a poultry littered soil near Vishakhapatnam. For this study, fifteen isolates of soil actinomycetes are initially screened in humic acid–salts vitamin agar plates. These isolates are then grown in Kim’s medium, containing olive oil as the sole source of carbon, for extracellular bio-surfactant activity. All these isolates are primarily screened for their bio-surfactant activity by oil-displacement method. Out of these fifteen, only four isolates namely, PLS-1, PLS-2, PLS-4, PLS-9, showed promising bio-surfactant activity compared to the standard, sodium laryl sulphate. These four promising isolates are further screened for their bio-surfactant activity by using various methods like parafilm-M method, lipase activity, surface tension measurement (Drop count method), and emulsification index. Among these four promising isolates, one isolate, from the poultry-littered soil (PLS-1), showed maximum bio-surfactant activity for the above tests and also showed positive result for various methods like, Phenol H 2 SO 4 and Blue Agar plate method. This indicates that the bio- surfactant is Rhamnolipid in nature. This result is further confirmed by orcinol assay, taking L-rhamnose as standard. It is concluded that actinomycetes isolate PLS-1 has potential as source of new antibacterial compounds against pathogenic microorganisms (unicellular Gram positive and Gram negative bacteria and drug resistance microorganism) in human-beings. Keywords: Actinomycetes, Antimicrobial activity, Bio-surfactants, Kim’s medium, Orcinol assay, Rhamnolipid. INTRODUCTION il pollution and remediation technology has become a Global phenomenon of increasing importance. Most of the hydrocarbons are insoluble in water and their degradation using microorganisms has an important role in combating environmental pollution. These bio-surfactants are extracellular products excreted by microbial cells grown on certain hydrocarbons, although it may be possible to produce them from other substrates such as carbohydrates. 1 The main characteristic of these microbial cultures is their ability to excrete relatively large amount of surface active substances that emulsify or wet the hydrocarbon phase, thus making them available for absorption. 2 Bio- surfactant producing microbes are present not only in oil contaminated soils, but also in undistributed soils like poultry soil, which is rich in organic matter suitable for the growth of diverse organisms. This soil is rich in bacteria, fungi and actinomycetes. Hydrocarbon degrading micro-organisms produce bio-surfactants of different chemical nature and molecular sizes, which are surface active compounds, increase the surface tension of the hydrophobic water-insoluble substrates, and thereby enhancing their bioavailability and the rate of bioremediation. 3 At present, almost all chemically synthesised surfactants are derived from petroleum. These synthetic surfactants are toxic and can be hardly degraded by microorganisms. Thus, these synthetic surfactants are a potential source of pollution and cause damage to the environment. Such hazards associated with synthetic surfactants have, in recent years, drawn much attention to bio-surfactants. 4 Bio-surfactants derived from micro-organisms have attracted much attention because of their advantageous characteristics such as structural diversity, low toxicity, higher biodegradability, better environmental compatibility, higher substrate selectivity, and lower CMC. These properties have led to several bio-surfactant applications in the food, cosmetic and pharmaceutical industries. 5 Most commonly isolated bio-surfactants are glycolipids and lipopeptides. They include rhamnolipid, released by Pseudomonas aeruginosa 6 , glycolipids from Rhodococcus erythropolis., and Rhodococcus aurantiacus, and surface active lipid from Nocardia erythropolis strains. 21 Thus, based on their chemical composition, the bio-surfactants produced by microorganisms are of many types such as glycolipids, lipopolysaccharides, oligosaccharides, and lipopeptides. 5,7 Bio-surfactants have many applications in environmental sector, like bio-remediation, soil washing, and soil flushing. Bio-surfactants influence these processes because of their efficacy as dispersion and remediation agents, environment friendly characteristics such as low toxicity and high bio-degradability. Although bio- surfactants exhibit such important advantages, they have not yet been employed extensively in industry because of relatively high production costs. 8 Isolation, Identification and Antimicrobial activity of Bio-surfactant from Streptomyces matensis (PLS-1) O Research Article