Chitinase Production by Trichoderma harzianum Grown on a Chitin-Rich Mushroom Byproduct Formulated Medium

Abstract

The aim of this work was to evaluate the use of chitin-rich mushroom (Agaricus bisporus) by-products chitin/glucan enriched fraction (M-Ch/G-F) as main carbon source for the production of chitinases by three different microorganisms (Trichoderma harzianum, Trichoderma atroviride and Bacillus licheniformis), in an attempt to obtain these enzymes using a cheap and abundant fermentation medium. Microorganisms were grown in submerged fermentation using different media formulated with chitin powder (Chp), colloidal chitin (Chc) and M-Ch/G-F as the main carbon source, respectively. Enzyme productivity and secretion (secretome) was studied by electrophoretic and proteomic methods. All microorganisms produced higher chitinase activity in a medium formulated with M-Ch/G-F as a carbon source compared to medium formulated with Chp or CHc. T. harzianum showed the highest chitinase productivity (261.5 mU L−1 per day). Chitinase production was monitored by electrophoretic and proteomic methods. Electrophoretic method allowed the detection of 28 different proteins—three different chitinases with 82, 50 and 31 kDa. Proteomic analysis could identify 161 different proteins: 60 of them hydrolases, and 80% having glycolytic activity—5 of them were chitinases. These results show that cultivation of T. harzianum in a cheap and abundant fermentation medium represents a good procedure for large scale production of chitinases. Our results show that cultivation of T. harzianum in a culture medium formulated with M-Ch/G-F, a cheap and abundant fermentation medium, is a good procedure for large scale production of glycosidases, particularly chitinases within a relatively short cultivation period of 6 days.