Expression of Trichoderma reesei β-Xylanase in Escherichia coli and its function in degradation of Juncao holocellulose

In this study, the xyn2 gene, which encodes an endo-beta-1,4-xylanase, was isolated with holocellulose extracted from Juncao Miscanthus floridulu as an inducer. The xyn2 gene expressed in Escherichia coli, with the estimated yield of 349 U.mL(-1). Zymogram analysis showed that the purified Xyn2 had only one band on SDS-PAGE with an estimated molecular mass of 28 kDa. Enzymology analysis demonstrated that its optimum activity was at pH 6.0 and 60 degrees C, with stability at pH range 4.0 similar to 7.0 and temperature up to 50 degrees C. The metal ions Cu2+ and Mg2+ showed some inhibition effects, while Fe2+ and Fe3+ had small stimulating effects. Its values of Km and Vmax are 2.85 mM and 50.2 mM/min, respectively. Based on our results, we propose a novel way to convert Juncao biomass into energy and other useful products.