Abstract

STANDARDIZATION OF OPTIMAL CULTURAL CONDITIONS OF AN ANTIBIOTIC PRODUCING SOIL ACTINOMYCETES FOR LARGE SCALE ANTIBIOTIC PRODUCTION

Bikas Kumar Kundu* and Prasanta Kumar Sircar

Abstract

The aim of our study was to standardize optimum cultural conditions of a soil Actinomycetes Nocardia sp. for large scale production of culture filtrate to isolate antibiotic. To standardize suitable culture medium for large scale production of antibiotic from soil actinomycetes, eleven different media were tested for submerged shake culture. The media were sterilized at 15lb for 20 minutes and sugar solutions were added to the media filtering through 0.45μm Millipore filter. The culture was incubated for 6 days at 35°C temperature. To determine the optimum temperature for antibiotic production, the producing strain was cultivated in a medium containing 0.5% peptone and 0.25% beef extract at pH 7.0 for 6 days at varying incubating temperatures of 15°C, 20°C, 25°C,30°C,35°C,40°C, 45°C and 50°C. For the study of pH optimum, pH 1 to pH 10 was adjusted in the nutrient medium composing 0.5% peptone and 0.5% beef extract and to determine the size of inoculum for maximum yield of antibiotic, 0.1 ml to 1.0 ml seed culture was utilized. The peak hour of antibiotic production was studied at 24 hours incubating intervals of submerged culture by determining the antibiotic potency in each interval. To study the antibiotic potency, the fermented broth was centrifuged followed by G-1 filtration to remove mycelial cake and free spores. Antibiotic sensitivity was assayed by cup assay against test organisms Bacillus subtilis and E. coli. The zones of inhibiting growth of test organisms were studied for comparison.

Keywords: Soil, Actinomycetes, Cultural Conditions, Standardization, Antibiotics.