Efficacy of chitinases from mangrove wetland derived Penicillium oxalicum on powdered chitin

Abstract

Chitin, an abundant polysaccharide in shrimp and crab shells, serves as a primary resource for producing glucosamine and chitosan oligosaccharides. Chemical hydrolysis is widely utilized in these processes, due to the limited efficacy of many chitinases on powdered chitin. Additionally, many chitinases perform much better on colloidal chitin, which still requires swelling of the powdered chitin with hydrochloric acid. In this study, chitinases from a mangrove isolated P. oxalicum were characterized and applied for the hydrolysis of chitin substrates. The enzyme mixture exhibited strong catalytic performance toward powdered chitin, achieving approximately 70% hydrolysis within 2 h at 65 °C℃ under scale-up conditions (40 L working volume in 50 L batch reactors). HPLC analysis confirmed a stepwise hydrolysis pattern from chitooligosaccharides to monomeric GlcNAc, indicating near-complete depolymerization. The GlcNAc productivity of the enzyme mixture toward powdered chitin was approximately 80% of that observed for colloidal chitin. The ability to directly degrade powdered chitin without acid pretreatment highlights its industrial potential for green and efficient chitin valorization. This enzyme offers a sustainable, pretreatment-free alternative for chitin waste bioconversion into high-value products.