Bioconversion of chitin waste using a cold-adapted chitinase to produce chitin oligosaccharides. (November 2020) - Fu, Xing
Abstract: Chitin waste, a highly insoluble biopolymer from sea food industry, can be converted into value-added products with chitinase (EC 3.2.1.14). Here, we purified a cold-adapted chitinase (EaChi39) from the marine bacterium Exiguobacterium antarcticum DW2. The enzyme was mostly activated at 30 °C and remained 35% of the maximal activity at 0 °C. It also showed a broad range of pH stability, high thermostability but low K m values, indicating the strong ability for chitin degradation. As an endo-type chitinase, EaChi39 completely converted colloidal chitin into N-acetylglucosamine (GlcNAc) and oligosaccharides with high yields, which was determined by HPLC (GlcNAc 9.9 mg mL −1, GlcNAc2 14.8 mg mL −1 and GlcNAc3 5.0 mg mL −1 ). As a novel chitinase from Exiguobacterium genus, EaChi39 displayed advantageous cold-adaptation and thermostability. It may be a superior candidate for bioconversion of seafood by-products in producing bioactive oligosaccharides. Highlights: A novel chitinase was purified from marine bacterium Exiguobacterium antarcticum. The chitinase (EaChi39) exhibited both cold-adapted and thermostable properties. The kinetic parameters and hydrolysis mode of EaChi39 were studied. Chitin waste was hydrolyzed by EaChi39 at low temperature. A high-yield chitin-oligosaccharides was obtained with the enzymatic hydrolysis.