Expression and Biochemical Characterization of a Novel Marine Chitosanase from Streptomyces niveus Suitable for Preparation of Chitobiose

Abstract

It is known that bioactivities of chitooligosaccharide (COS) are closely related to the degree of polymerization (DP); therefore, it is essential to prepare COS with controllable DP, such as chitobiose showing high antioxidant and antihyperlipidemia activities. In this study, BLAST, sequence alignment and phylogenetic analysis of characterized glycoside hydrolase (GH) 46 endo-chitosanases revealed that a chitosanase Sn1-CSN from Streptomyces niveus was different from others. Sn1-CSN was overexpressed in E. coli, purified and characterized in detail. It showed the highest activity at pH 6.0 and exhibited superior stability between pH 4.0 and pH 11.0. Sn1-CSN displayed the highest activity at 50 °C and was fairly stable at ≤45 °C. Its apparent kinetic parameters against chitosan (DDA: degree of deacetylation, >94%) were determined, with Km and kcat values of 1.8 mg/mL and 88.3 s−1, respectively. Cu2+ enhanced the activity of Sn1-CSN by 54.2%, whereas Fe3+ inhibited activity by 15.1%. Hydrolysis products of chitosan (DDA > 94%) by Sn1-CSN were mainly composed of chitobiose (87.3%), whereas partially acetylated chitosan with DDA 69% was mainly converted into partially acetylated COS with DP 2-13. This endo-chitosanase has great potential to be used for the preparation of chitobiose and partially acetylated COS with different DPs.

Heterologous Expression and Characterization of a High-Efficiency Chitosanase From Bacillus mojavensis SY1 Suitable for Production of Chitosan Oligosaccharides

“…However, the chitosanase from Streptomyces roseolus , Acinetobacter calcoaceticus TKU024, and Serratia marcescens TKU011 are inhibited by Mn 2+ ( Wang et al, 2008 , 2011 ; Jiang et al, 2012 ). In this study, the relative activity of CsnBm was increased by 10% in the presence of Zn 2+ , similar to the chitosanases from Staphylococcus capitis and Streptomyces niveus ( Sun et al, 2018 ; Chen et al, 2021 ). On the contrary, the chitosanase from Aspergillus sp.…”

Overexpression and Biochemical Properties of a GH46 Chitosanase From Marine Streptomyces hygroscopicus R1 Suitable for Chitosan Oligosaccharides Preparation

“…Different from Csn21c, the chitosanase from S. roseolus is stable from pH 5.0 to 7.0 and the residual activity decreased sharply when reaction pH is above 7.0 (Jiang et al, 2012). Furthermore, the chitosanase Sn1-CSN from S. niveus is stable from pH 4.0 to 11.0 and the residual activity is above 80% even when the incubation time is 120 h (Chen et al, 2021). In this study, ShCsn46 is active and stable from pH 4.5 to 6.0, which is suitable for preparation of COSs.…”

“…SirexAA-E, and Streptomyces sp. N174 are 7.4, 1.8, 1.3, 2.2, and 0.026 mg/ml, respectively (Lacombe-Harvey et al, 2013;Takauka et al, 2014;Guo et al, 2019Guo et al, , 2021Chen et al, 2021).…”

“…Analyzing chitosanases from different Streptomyces, we found that the optimal temperatures of most reported Streptomyces chitosanases are 50 • C. However, the thermal stability varies differently between Streptomyces chitosanases. The chitosanase Sn-CSN from S. niveus is stable below 35 • C (Chen et al, 2021). Otherwise, the chitosanase from Streptomyces roseolus (S. roseolus) shows excellent thermal stability and the residual activity is above 90% after treatment at 60 • C for 30 min (Jiang et al, 2012).…”

“…Until now, some chitosanases from Streptomyces have been reported and characterized (Viens et al, 2015). Most of the reported Streptomyces chitosanases exhibit great potential to prepare COSs (Jiang et al, 2012;Sinha et al, 2012;Chen et al, 2021;Guo et al, 2021). It has been reported that the production level of Streptomyces chitosanases in wild-type strain are far beneath what is needed for industrial scale application (Thadathil and Velappan, 2014).…”