Biochemical characterization of a novel xylanase from Paenibacillus barengoltzii and its application in xylooligosaccharides production from corncobs

A novel xylanase gene (PbXyn10A) from Paenibacillus barengoltzii was cloned and expressed in Escherichia coli. PbXyn10A had an open reading frame of 3,063 bp, and its deduced amino acid sequence shared the highest identity of 72% with a xylanase from Paenibacillus curdlanolyticus. The recombinant xylanase (PbXyn10A) was purified and biochemically characterized. PbXyn10A was most active at pH 6.5 and 60 degrees C, respectively. It exhibited strict substrate specificity towards birchwood xylan, beechwood xylan and oat-spelt xylan, with Km values of 2.19, 2.04 and 2.51 mg/mL, respectively. The enzyme hydrolyzed xylan to yield mainly xylooligosaccharides (XOS) with degree of polymerization 2-4. A new strategy for XOS production from corncobs pretreated by steam explosion using acidic electrolyzed water, followed by enzymatic hydrolysis was developed. The highest XOS yield of 75% (based on xylan in raw corncobs) was achieved. This is the first report on a xylanase from Paenibacillus barengoltzii.