Isolation of four xylanases capable of hydrolyzing corn fiber xylan from Paenibacillus sp. H2C.

Abstract

Corn fibre xylan (CX) shows high resistance to enzymatic hydrolysis due to its densely decorated side chains. To find enzymes capable of hydrolyzing CX, we isolated a bacterial strain (named H2C) from soil, by enrichment culture using non-starch polysaccharides of corn as the sole carbon source. Analysis based on the 16S rRNA sequence placed strain H2C within genus Paenibacillus. Enzymes were purified from supernatant of culture broth of strain H2C based on solubilizing activities toward CX. Four enzymes, Xyn5A, Xyn10B, Xyn11A, and Xyn30A, were successfully identified, which belong to glycoside hydrolase (GH) families, 5, 10, 11, and 30, respectively. Phylogenetic analysis classified Xyn5A in subfamily 35 of GH family 5, a subfamily of unknown function. Their activities toward beechwood xylan and/or wheat arabinoxylan indicated that these enzymes are β-1,4-xylanases. They showed high solubilizing activities toward a feed material, corn dried distiller's grains with solubles, compared to five previously characterized xylanases.Abbreviations : CX: corn fibre xylan; DDGS: corn dried distiller's grains with solubles.