Efficient Production of N-Acetyl-β-D-Glucosamine from Shrimp Shell Powder Using Chitinolytic Enzyme Cocktail with β-N-Acetylglucosaminidase from Domesticated Microbiome Metagenomes

Abstract

The conventional methods used to produce N-acetyl-β-D-glucosamine (GlcNAc) from seafood waste require pretreatment steps that use acids or bases to achieve the extraction and decrystallization of chitin prior to enzymatic conversion. The development of an enzymatic conversion method that does not require the pretreatment of seafood waste is essential for the efficient and clean production of GlcNAc. In this study, the annotated metagenomic assembly data of domesticated microbiota (XHQ10) were analyzed to identify carbohydrate-active enzymes (CAZymes), and an in-depth analysis of the high-quality genome FS13.1, which was obtained from metagenomic binning, was performed; this enabled us to elucidate the catabolic mechanism of XHQ10 by using shrimp shell chitin as a carbon and nitrogen source. The only β-N-acetylglucosaminidase (named XmGlcNAcase) was cloned from FS13.1 and biochemically characterized. The direct production of GlcNAc from shrimp shell powder (SSP) via the use of a chitin enzyme cocktail was evaluated. Under the action of a chitin enzyme cocktail containing 5% recombinant XmGlcNAcase and a crude XHQ10 enzyme solution, the yield and purity of the final conversion of SSP to GlcNAc were 2.57 g/L and 82%, respectively. This is the first time that metagene-derived GlcNAcase has been utilized to achieve the enzymatic conversion of untreated seafood waste, laying the foundation for the low-cost and sustainable production of GlcNAc.