Evaluation of antifungal potential of chitin and chitin-based derivatives against pathogenic fungal strains

Abstract

Chitin, a predominant polysaccharide besides cellulose is present as an important constituent of exoskeleton of arthropods and crustaceans. It is also found as the important component of fungal hyphae. Chitin and its derivatives had a great significance and importance in pharmacological, medical and food dealing fields. In the present investigation, chitinous wastes were collected from the fresh water areas of Dehradun and Rishikesh of Uttarakhand State. The bacterium, Bacillus sp. isolated from soil produces chitinase enzyme responsible for degradation of chitin obtained from chitinous wastes. Further the chitinases enzyme was utilized to degrade the chitinous wastes into chito-oligosaccharides. The chitin active molecule present in the chitinous waste at another stage was deacetylated to chitosan. Further the antifungal activity of chitinases, chitin, chitosan and chito-oligosaccharides was determined in vitro by well diffusion method against Aspergillus niger and Candida albicans. Amongst the test fungal cultures, the chitinase showed maximum inhibition against Aspergillus niger (diameter of zone of inhibition: 24 mm) followed by Candida albicans (diameter of zone of inhibition: 14 mm). Deacetylated form of chitin i.e chitosan showed potent antifungal activity against Candida albicans (diameter of zone of inhibition: 24 mm) followed by Aspergillus niger (diameter of zone of inhibition: 18 mm). The chitin extracted showed almost similar antifungal activity against Aspergillus niger and Candida albicans (diameter of zone of inhibition: 15 mm) respectively. The low molecular weight derivatives viz. chito-oligosaccharide showed significant antifungal activity against Aspergillus niger (diameter of zone of inhibition: 14 mm) but no activity was found against Candida albicans.