Isolation of antibiotics produced from streptomyces stock culture

Description

Isolation of antibiotics produced from streptomyces stock culture.

Abstract

This research on the Isolation of Antibiotics Produced from Streptomyces Stock Culture is aimed at isolating, evaluating and characterizing potential antibiotics produced from the stock culture. A total of 31 strains of Streptomyces were isolated and tested against Gram-positive and Gram-negative bacterial strains by primary screen. In the primary screening, 11 promising isolates were identified and subjected to solid state and submerged state fermentation methods to produce crude extract. The fermented biomass was extracted by organic solvent extraction method and tested against bacterial strains by disc agar well diffusion methods. The isolates were characterized by using morphological, physiological and biochemical methods. The result, obtained from the agar well diffusion method was better than that of the disc diffusion methods. The crude extract showed a higher inhibition zone against Gram-positive bacteria that Gram-negative bacteria. One-way analysis of variance confirmed most of the crude extract were statistically significant at 95% confidence interval. The minimum inhibitory concentration and minimum bactericidal concentration of crude extracts were I.65 mg/mL and 3.30 mg/mL against Staphylococcus aureus and 1.84 mg/mL and 3.80 mg/mL against Escherichia coli respectively. The growth of aerial and substrate mycelium varied in different culture media used. Most of the isolates were able to hydrolyze starch and urea, able to survive 5% concentration of sodium chloride, and the optimum temperature for their growth was 30 °C.