Screening of a Novel Glycoside Hydrolase Family 51 α-L-Arabinofuranosidase from <i>Paenibacillus polymyxa</i> KF-1: Cloning, Expression, and Characterization

Paenibacillus polymyxa exhibits remarkable hemicellulolytic activity. In the present study, 13 hemicellulose-degrading enzymes were identified from the secreted proteome of P. polymyxa KF-1 by liquid chromatography-tandem mass spectrometry analysis. &#945;-L-arabinofuranosidase is an important member of hemicellulose-degrading enzymes. A novel &#945;-L-arabinofuranosidase (PpAbf51b), belonging to glycoside hydrolase family 51, was identified from P. polymyxa. Recombinant PpAbf51b was produced in Escherichia coli BL21 (DE3) and was found to be a tetramer using gel filtration chromatography. PpAbf51b hydrolyzed neutral arabinose-containing polysaccharides, including sugar beet arabinan, linear-1,5-&#945;-L-arabinan, and wheat arabinoxylan, with L-arabinose as the main product. The products from hydrolysis indicate that PpAbf51b functions as an exo-&#945;-L-arabinofuranosidase. Combining PpAbf51b and Trichoderma longibrachiatum endo-1,4-xylanase produced significant synergistic effects for the degradation of wheat arabinoxylan. The &#945;-L-arabinofuranosidase identified from the secretome of P. polymyxa KF-1 is potentially suitable for application in biotechnological industries