An efficient enzymatic production of N-acetyl-d-glucosamine from crude chitin powders

In this study, we present an efficient affinity adsorption-enzymatic reaction integrated approach to produce N-acetyl-d-glucosamine (GlcNAc) from crude chitin powders (CP). Chitinase was first purified from the crude enzyme mixture by affinity adsorption on the CP substrate, with ∼92.7% recovery of the enzyme achieved within 10 minutes in the presence of 20 g L^-1 of CP under optimized conditions. The chitinase then efficiently converted 40 g L^-1 of CP to 39.3 g L^-1 of GlcNAc in a batch enzymatic reaction for 4 days, achieving nearly 100% conversion of the substrate CP. The product GlcNAc was easily separated from hydrolysates after destaining, concentrating, crystallizing and drying processes with a high purity of 98%. In addition, the chitinase can be conveniently reused for several batches by the affinity adsorption-enzymatic reaction approach, giving an average yield of 29.6 g L^-1 of GlcNAc based on 30 g L^-1 of CP as the substrate.