Optimisation of process parameters for growth and bioactive metabolite produced by a salt-tolerant and alkaliphilic actinomycete, Streptomyces tanashiensis strain A2D

An alkaliphilic actinomycete, Streptomyces tanashiensis strain A2D isolated from soil of phoomdi in Loktak Lake of Manipur, India exhibited optimum growth at 2% (w/v) NaCl and pH 8. It is Gram-positive filamentous bacterium which exhibits a broad spectrum of antimicrobial activity against fungi and bacteria. Optimum salt and pH for antibiotic production were 2% (w/v) and 8 respectively. Studies on nutritional factors revealed that highest antibiotic production was obtained when glucose and soyabean meal at 1% (w/v) were used as carbon and nitrogen sources respectively. Seven days of incubation at 28 degrees C. was found to be the optimum for antibiotic production by the strain. The antimicrobial agent produced by the strain was extracted with ethyl acetate as solvent and purified by TLC. The purified active compound with lambda(max) 241.99 nm has got the lowest minimum inhibitory concentration (MIC) against Staphylococcus aureus (50 mu g/ml), whereas highest (100 mu g/ml) was recorded against Candida albicans and Fusarium moniliform. So far only few alkaliphilic actinomycetes have been explored for their antimicrobial potential. (C) 2009 Elsevier Masson SAS. All rights reserved.