Abstract

ANTIMICROBIAL ACTIVITY OF BACILLUS SP. JG: ISOLATION, IDENTIFICATION AND PROCESS OPTIMIZATION FOR THE PRODUCTION OF ANTIMICROBIAL METABOLITE AGAINST HUMAN PATHOGENS

Jyoti Handa and Pranay Jain*

ABSTRACT

Antibiotic resistance in bacteria has become a serious problem. Therefore, the search for new antibiotics is an important endeavour and is very much needed. In the present investigation, a number of bacterial strains were isolated from different soil samples and were tested for antimicrobial metabolite production. 85 bacterial isolates were isolated and the best activity was exhibited by the bacterial isolate P13. Physiological, biochemical and 16S rDNA gene sequence analysis strongly suggested that the isolate P13 belonged to Bacillus sp. Effect of medium, incubation period, pH and temperature variations for the maximum production of antimicrobial metabolite were optimized for maximum antimicrobial metabolite production. The maximum production of antimicrobial metabolite was observed in WYH under pH 7.0 and incubation temperature of 35oC. Nutritional and culture conditions for the production of antimicrobial metabolite by this organism under shake-flask conditions were also optimized. Dextrose and peptone were found to be the best carbon and nitrogen sources for the production of antimicrobial metabolite by Bacillus sp. JG. Chloroform was the best extraction solvent for the isolation of the antimicrobial metabolite. The minimum inhibitory concentration of the metabolite against the test pathogens ranged between 0.9 to 2mg/ml. It may be suggested from the present study that further research is needed for determining the chemical structure of metabolite which is responsible for bio-efficacy and to determine the cytotoxicity before it is used for commercialization purposes.

Keywords: Antimicrobial metabolite; MIC; Optimization, Bacillus sp. JG.