Bioactive actinomycetes from Krishna River sediments of Andhra Pradesh.

Sediment samples from Krishna River at Nagayalanka of Andhra Pradesh, India were investigated as a source of actinomycetes to screen for the production of novel bioactive compounds. During our investigation on fresh water actinomycetes from 5 different river sediment samples, a total of 80 actinomycetes were isolated. Out of these 80 isolates, 30 isolates which showed distinct macromorphological characteristics were selected. The antimicrobial and enzymatic activities were studied for all the 30 isolates. The preliminary study for antimicrobial activity by cross streak method indicated that 16 isolates (53.3%) have excellent antagonistic properties. All these 16 isolates were subjected to detailed submerged fermentation studies. It was observed that 12 isolates (40.0%) exhibited antibacterial activity, 9 isolates (30.0%) showed antifungal activity while 5 isolates (16.6%) showed both antibacterial and antifungal activities. All the 30 isolates were also subjected for the determination of enzymatic activities 25 isolates (83.3%) exhibited amylolytic activity while 27 isolates (90.0%) showed proteolytic activity. Among these isolates, six promising isolates were selected for detailed morphological, cultural, physiological and biochemical studies. It was established that these isolates belong to the Streptomyces genus by virtue of their cell wall composition pattern and were identified as strains of different Streptomyces species like S. rochei, S. alanosinicus, S. erumpens, S. griseoplanus, S. gancidicus and S. nigrogriseolus.