Tailoring the Microbial Community for Improving the Biodegradation of Chitosan Films in Composting Environment

The use of chitosan is increasing in various industries, resulting in increased generation of chitosan-containing waste. Composting is the foremost method for management of such wastes, rendering it important to understand microbial diversity and effects of microbial inoculation on biodegradation process. Here, we investigated biodegradation of chitosan films in controlled composting reactors and analyzed microbial diversity via PCR-denaturing gradient gel electrophoresis (DGGE). Then, we assessed the effects of microbial inoculation on chitosan biodegradation and monitored changes in microbial diversity in composting reactors. The dominant taxonomic groups at phylum level were Ascomycota and Proteobacteria. CO₂ emission data showed high degradation rate of chitosan in reactors inoculated with Group-I microorganisms, which are capable of producing chitosanase. This result was supported by the data obtained from TG and FTIR analyses. Compared with the control reactor containing only chitosan films (without microbial inoculum), Group-I inoculant improved the efficiency of chitosan biodegradation in composting reactors, while Group-II inoculant decreased the degradation rate. We have shown that appropriate selection of microbial strains for inoculum is important for chitosan biodegradation; specifically, strains producing different subclasses of chitosanase can be included. Thus, design and optimization of microbial community used for chitosan biodegradation will increase the efficiency of the process.