Antimicrobial potential of chitosan extracted from Bacillus sp. by optimization of growth culture

Abstract

Chitosan (-1,4-D-glucosamine), the deacetylated form of chitin, owing to its unique biocompatible, biodegradable, nonantigenic and nontoxic potential, has multiple applications, such as nanoparticles synthesis, drug delivery, dye removal, and as thickening as well as antimicrobial agent. However, production of chitosan involves harsh chemical process. It is neither economical nor environment friendly. Apart from marine organisms, bacteria are also good source of chitosan. Here, we report an alternative cost effective method for production of chitosan from enzymatic deacetylation of bacterial chitin under controlled laboratory conditions. We screened bacterial strains from East Kolkata Wetland area that acts as a natural incubator for microorganisms with rich diversity and identified potential chitosan producing strains. The bacterial isolates, BRS 5 and PS 4 yielded 2 and 0.3% chitosan, respectively. The positive colonies (BRS 5 and PS 4) also showed antibacterial and antifungal activity against E. coli and Candida albicans ATCC 60193. The production of chitosan was optimized by optimizing the bacterial growth against different carbon source, such as glucose, lactose, maltose, fructose and starch in different pH (4-9), and different temperatures (20-45°C) to achieve an increased production rate.