Identification of a New 1,4-beta-D-xylosidase <italic>Pae</italic>1263 from the Whole Genome Sequence of <italic>Paenibacillus terrae</italic> HPL-003.

The gene of <italic>Pae</italic>1263 (2,196 bp, 732 aa) was found from the full-length sequence analysis of bacterium <italic>Paenibacillus terrae</italic> HPL-003 isolated from soil on Gara Mountain in Korea (CP003107, our previous study). Among the 20 open reading frames (ORFs) related with the xylose substrate, only the recombinant enzyme of ORF <italic>Pae</italic>1263 showed a 1,4-beta-D-xylosidase activity when all of the ORFs were transformed into <italic>E. coli</italic>. This gene is considered to be a new 1,4-beta-D-xylosidase because it has up to 93% similarity with other genes of ZP_10240221.1 from <italic>Lactococcus raffinolactis</italic> 4877 and ZP_11237858.1 from <italic>Paenibacillus peoriae</italic> in the GenBank blast search. The enzyme activity was confirmed by HPLC in which xylose was produced from xylobiose as a substrate by this recombinant enzyme. Mass production of the recombinant enzyme was done with the construction of the pET22(+)- <italic>Pae</italic>1263-6H expression vector system from <italic>E. coli</italic>. This new 1,4-beta-D-xylosidase was highly active at 50°C in a pH range between 6.0 and 8.0 and had thermo-stability for at least 24 h at 50°C and a <italic>K</italic><italic>m</italic> and <italic>V</italic><italic>max</italic> of 6.42 mg/mL and 75.76 U/mg on a xylobiose substrate, respectively. [ABSTRACT FROM AUTHOR]