earticle

영어

A new xylanase gene, KRICT PX3, isolated from Paenibacillus sp. HPL-003 (KCTC18179P), has been cloned and expressed in Escherichia coli. This gene encodes 540 amino acid residues (1,620bp) including 179 amino acid residues of a signal peptide, and the deduced amino acid sequence of KRICT PX3 showed 48% identity to endo-1,4-b-xylanase (YP_001817989) from Opitutus terrae PB90-1 among the xylanases of Glycosyl hydrolase 10 superfamily. Purified recombinant xylanase KRICT PX3 showed an thermostable, wide pH spectrum, and high activity on the different-origin of xylan. The specific activity of the purified xylanase KRICT PX3 at pH 7 and 50oC was 125 U, and exhibited Km and Vmax values of 0.2 mg/ml and 153.8 U/mg on birch wood xylan, respectively. This enzyme has a wide pH spectrum of pH 5 to pH 11. Optimum temperature was estimated at the range of 50~60oC and it was stable for 24 hrs at 50oC, however, easily lost the activity at 60oC after 20 min. Most salts did not significantly change the enzyme activity, and also ethylenediamine tetra-acetic acid, 2-mercaptoethanol, phenylmethanesulphonyl fluoride, and furfural were not influenced on the enzyme activity at 1 mM, however, Cu+2, Zn+2, Fe+2, and EDTA was slightly inhibited the enzyme activity. Thin layer chromatography analysis showed that the enzyme released a mixture of hydrolysis products including xylobiose, xylotriose and some of xylooligomers from birchwood xylan. Further research on the practical application will be necessary for the industrial usage.