Characterization of a New Chitosanase from a Marine Bacillus sp. and the Anti-Oxidant Activity of Its Hydrolysate.

Chunrui Ma,Kun Yang,Shangyong Li,Xiao Li

doi:10.3390/md18020126

Abstract

Chitooligosaccharide (COS) has been recognized to exhibit efficient anti-oxidant activity. Enzymatic hydrolysis using chitosanases can retain all the amino and hydroxyl groups of chitosan, which are necessary for its activity. In this study, a new chitosanase encoding gene, csnQ, was cloned from the marine Bacillus sp. Q1098 and expressed in Escherichia coli. The recombinant chitosanase, CsnQ, showed maximal activity at pH 5.31 and 60 °C. Determination of CsnQ pH-stability showed that CsnQ could retain more than 50% of its activity over a wide pH, from 3.60 to 9.80. CsnQ is an endo-type chitosanase, yielding chitodisaccharide as the main product. Additionally, in vitro and in vivo analyses indicated that chitodisaccharide possesses much more effective anti-oxidant activity than glucosamine and low molecular weight chitosan (LMW-CS) (~5 kDa). Notably, to our knowledge, this is the first evidence that chitodisaccharide is the minimal COS fragment required for free radical scavenging.

Highlights

IntroductionN-acetyl-D-glucosamine (GlcNAc), is the second most abundant natural biomass after cellulose on earth [1]
Chitin, an insoluble linear poly-acetylaminosaccharide made up of β-1,4-linkedN-acetyl-D-glucosamine (GlcNAc), is the second most abundant natural biomass after cellulose on earth [1]
Based on the National Center for Biotechnology Information (NCBI) conservative domain database (CDD) search, CsnQ was found to be a putative chitosanase with its conservative domain belonging to family GH46

Summary

Introduction

N-acetyl-D-glucosamine (GlcNAc), is the second most abundant natural biomass after cellulose on earth [1]. As its most important derivative, chitosan is a biopolymer obtained by partial or complete deacetylation of chitin, and consists of GlcNAc and D-glucosamine (GlcN) residues [2]. Chitosan has immense potential for application in multiple fields owing to its unusual physicochemical properties such as biocompatibility, biodegradability and low toxicity [1]. Chitooligosaccharide (COS), is water-soluble, less viscous and low molecular weight depolymerized derivative of chitosan, and is commonly superior to chitosan polymers in several aspects [1]. COS has been a subject of considerable attention in terms of its role in many biological applications, which correlates well with its antimicrobial [4], anti-inflammatory [5], anti-oxidant [6], anti-photoaging [7], anti-tumor [8] activities as well as immuno-enhancer effects [9]

Methods

Results

Conclusion