Expression, purification and characterization of xylanase from alklinphilic bacterium Cellulomonas bogoriensis 69B4T

Abstract:

[Objective] This study aims to investigate the production of alkaline xylanase from alkaliphilic bacterium Cellulomonas bogoriensis 69B4^T; clone the xylanase genes derived from this strain; and perform heterologous expression, purification, and characterization of the enzymatic properties.[Methods] We used the single-factor culture method to study the alkaline xylanase production of the strain and cloned five endo-xylanase genes through the homologous amplification. We expressed recombinant xylanases in Escherichia coli and purified them using the affinity chromatography. The enzymatic properties of purified enzymes were characterized using xylan as substrate.[Results] Five xylanases, i.e., Xyn370, Xyn393, Xyn425, Xyn466, and Xyn486, derived from C. bogoriensis69B4^T achieved heterologous expression in E. coli and obtained pure enzyme components. Their optimal temperature was 60℃, 50℃, 40℃, 40℃, and 60℃, and the remaining enzyme activity was more than 90% when kept at 50℃ for 2 h. The optimum pH for Xyn370, Xyn393, Xyn425, Xyn466, and Xyn486 were 7.0, 8.0, 8.0, 8.0, and 9.0, respectively. The five recombinant xylanases had good stability at a pH range of 5.0-9.0 and showed good tolerance to some metal ions and high salt concentrations, and the enzyme activity on beech xylan was the highest. All xylanases were endo-xylanases.[Conclusion]] The five recombinant xylanases expressed and purified in this paper have excellent salt and alkali resistance and are resistant to temperature, certain metal ions, and chemical reagents, providing novel enzymes for studying the alkali resistance mechanism and the industrial applications of the xylanase source.