CLONING, EXPRESSION, AND CHARACTERIZATION OF AN ALKALOPHILLIC ENDO-1,4-BETA-XYLANASE FROM PAENIBACILLUS SP. HPL-002

The biochemical properties of a purified enzyme of a new alkalophillic endo-1,4-beta-xylanase gene, KRICT PX2 (GU967374), which was isolated from Paenibacillus sp. HPL-002 (KCTC11410BP) and expressed in E. coli, were investigated. The specific activity of the purified xylanase was 51.26 μmol/min/mg proteins. The Km and Vmax values of the protein for birch wood xylan were also verified to have 0.061 μM and 55.3 μmol/min/mg proteins, respectively. The optimum pH and temperature for the activity of the enzyme were pH 8~9 and 50oC, respectively, and, the activity was stably maintained at 40oC. Most metallic salts, ethylenediamine tetra-acetic acid, 2-mercaptoethanol, phenylmethane-sulphonyl fluoride, and furfural, have no impact on the enzyme’s activity at 1 mM. The simulated 3-D structure of this xylanase is similar to Xyn10B from Paenibacillus barcinonensis. Further research on the degradation of different-origin xylans and enzyme production will be necessary for practical applications.