Bioconversion of chitin waste using a cold-adapted chitinase to produce chitin oligosaccharides

摘要

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 degrees C and remained 35% of the maximal activity at 0 degrees 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), GlcNAc(2) 14.8 mg mL(-1) and GlcNAc(3) 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.