earticle

영어

Xylosidases, a hemicellulase enzyme group that hydrolyze the short xylooligomer to final product of xylose, is an importance enzyme in biomass degradation. In this study, we reported the characterization of a recombinant putative gene that encodes for beta-xylosidase from biomass degradation white-rot fungus Phanerochaete chrysosporium. The beta-xylosidase gene was obtained from cDNA library of P. chrysosporium. Sequence analysis indicated that beta-xylosidase cDNA gene consists 1797 nucleotides, encodes for 598 amino acids. The beta-xylosidase gene was then searched blast against available nucleotide database on NCBI. The results showed that beta-xylosidase matched to beta-xylosidase of Clostridium acetobutylicum, Geobacillus stearothermophilus and Bacillus halodurans at 28-30% similarity. Enzymatic assay on p-nitrophenyl-beta-xylopyranoside resulted optimum pH and temperature of 5 and 45OC, respectively. Mg2+, Mn2+ and Fe3+ increased enzyme activity where as Zn2+, Ca2+ and Fe2+ inhibited xylosidase activity. Thin layer chromatography analysis of end product of enzyme on xylooligomer indicated the enzyme act as exo-type. The enzyme did not hydrolyze xylan substrates such as birchwood xylan, beechwood xylan and arabinoxylan but it hydrolyzed p-nitrophenyl-alph-L-arabinofuranoside, resulting that beta-xylosidase have two biocatalytic domains.