Effect of organic solvents treatment on structure of chitin and its enzymatic hydrolysis

Abstract In this study, the effect of pretreatment with three organic solvent systems on enzymatic hydrolysis of chitin was investigated. Firstly, genes coding three chitinolytic enzymes CmChi1, CmChi4, and CmNAGase from Chitinolyticbacter meiyuanensis SYBC-H1 were cloned and functionally expressed. Then, a cocktail capable of producing GlcNAc from chitin was formulated with 71.4% recombinant CmChi1, 23.8% recombinant CmChi4, and 4.8% recombinant CmNAGase. Next, three organic solvent systems, including LiCl/dimethylacetamide, CaCl2/Methanol, and hexafluoroisopropanol were applied to treat chitin, resulting in 4.90–8.21-fold improvement of hydrolysis efficiency compared to raw chitin. The decreased crystallinity and nanofiber size structure without deacetylation, confirmed by SEM, FTIR, XRD, and EA, aided in the increased efficiency. Finally, yields of 20.97 mM, 34.50 mM, and 32.53 mM of GlcNAc with a purity of 96% were respectively obtained from 10 g/L of CLD, CHP, and CCM in 24 h.