Productin and characterization of fungal chitin and chitosan

by Wu, Tao.

Chitin is a biopolymer. Theoretically, it is a homopolymer of acetyl-glucosamine. Chitosan is the deacetylated product of chitin. Chitin and chitosan have many applications in water purification, agriculture, food and pharmaceutical industries. Currently, industrial production for chitin and chitosan is from the shell wastes. The objective of this study was to evaluate the feasibility of chitin and chitosan production from fungal sources. The accumulation of chitin and chitosan during A. bisporus storage and Aspergillus niger and Mucor. rouxii. Growth was evaluated by total glucosamine determination. Chitin and chitosan were extracted from biomass by alkali and acid treatment and yield and composition (glucosamine and glucan) of extracted material were analyzed. The Degree of acetylation (DA) and crystallinity were analyzed by HPLC and FT – IR, respectively. The antimicrobial activity against Salmonella Typhimurium DT104 2576 and the induction of apple defense response against Botrytis cinerea and Penicillium expansum were also evaluated. Results showed Agaricus bisporus, Aspergillus niger and Mucor rouxii have excellent potentials to be used for chitin and chitosan production on industrial scale with maximum chitin/chitosan content of 19 %, 12 % and 20 % in dry mycelia, respectively. Fungal chitin from all 3 species had lower DA compared with shrimp chitin. Native fungal chitosan had DA comparable with commercial available chitosan. Fungal chitin and chitosan did not show significant antimicrobial activity against Salmonella Typhimurium DT 104 in TSB with pH 4.5 at 25 ºC. Chitin and chitosan extracted from 3 species showed strong ability to induce apple defense reaction against Botrytis cinerea and Penicillium expansum. v