Fungal biosynthesis of endochitinase and chitobiase in solid state fermentation and their application for the production of N-acetyl-d-glucosamine from colloidal chitin
Abstract
The present study was directed to the production of N-acetyl-d-glucosamine using endochitinase and chitobiase from fungal cultures in solid culturing. Fifteen fungal strains were evaluated for endochitinase and chitobiase production under solid-state fermentation using agro-industrial residues, of which Penicillium aculeatum NRRL 2129 showed maximum endochitinase activity whereas Trichoderma harzianum TUBF 927 showed maximum chitobiase activity. Eleven substrates, alone and in combination with chitin, were evaluated for the enzyme production. Optimization of physico-chemical parameters such as incubation period and initial moisture content, and nutritional parameters such as chitin source, inorganic and organic nitrogen sources, were carried out. Optimization resulted in more than 3-fold increase in endochitinase production (from 3.5 to 12.53 U/g dry weight of substrate) and about 1.5-fold increase in chitobiase production (from 1.6 to 2.25 U/g dry weight of substrate). Studies on the degradation of colloidal chitin to N-acetyl-d-glucosamine showed improved efficiency when endochitinase and chitobiase were used in combination.