earticle

영어

Chitinolytic and chitosanolytic microorganisms are widely distributed in nature. Biological and enzymatic activities of these enzymes are applied to produce hydrolytic oligosaccharides which have various biological functions involved in anticancer, antimicrobial activities, immune-stimulating activities and so on. In the present study, we describe the biological characteristics including the diversity based on 16S rDNA sequence analysis, production of chitosanase and its hydrolysates, and enzyme activities. Among 15 species of chitosanolytic microorganisms isolated in this study, one named as Bacillus subtilis JH-1122 based on 16s rDNA sequence homology search has shown the highest similarity with most of sub-species of Bacillus. Various sizes of chitosan hydrolysates (Low Molecular Weight Chitosan, LMWC) ranging from 3 to 60 kDa were prepared to assess the effect of molecular weight on antimicrobial activity by enzymatic digestion of chitosan using chitosanase isolated and partially purified from the culture medium of Bacillus subtillis JH-1122. Especially it has shown the higher antimicrobial activity toward antibiotics resistant microorganisms such as Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa. These results suggest that LMWC may be a predominant factor either directly or indirectly affecting on broad antimicrobial activities.