Summary 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 pH8. 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 8C. 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 lmax 241.99 nm has got
the lowest minimum inhibitory concentration (MIC) against Staphylococcus aureus (50 mg/ml),
whereas highest (100 mg/ml) was recorded against Candida albicans and Fusarium moniliform. So
far only few alkaliphilic actinomycetes have been explored for their antimicrobial potential.