Biochemical characterization of a novel bifunctional chitosanase from Paenibacillus barengoltzii for chitooligosaccharide production

AbstractA novel chitosanase gene, designated asPbCsn8, was cloned fromPaenibacillus barengoltzii. It shared the highest identity of 73% with the glycoside hydrolase (GH) family 8 chitosanase fromBacillus thuringiensis JAM-GG01. The gene was heterologously expressed inBacillus subtilis as an extracellular protein, and the highest chitosanase yield of 1, 108 U/mL was obtained by high-cell density fermentation in a 5-L fermentor. The recombinant chitosanase (PbCsn8) was purified to homogeneity and biochemically characterized. PbCsn8 was most active at pH 5.5 and 70  °C, respectively. It was stable in a wide pH range of 5.0–11.0 and up to 55 °C. PbCsn8 was a bifunctional enzyme, exhibiting both chitosanase and glucanase activities, with the highest specificity towards chitosan (360 U/mg), followed by barley β-glucan (72 U/mg) and lichenan (13 U/mg). It h ydrolyzed chitosan to release mainly chitooligosaccharides (COSs) with degree of polymerization (DP) 2–3, while hydrolyzed barley β-glucan to yield mainly glucooligosaccharides with DP >  5. PbCsn8 was further applied in COS production, and the highest COS yield of 79.3% (w/w) was obtained. This is the first report on a GH family 8 chitosanase fromP. barengoltzii. The high yield and remarkable hydrolysis properties may make PbCsn8 a good candidate in industrial application.
Source: World Journal of Microbiology and Biotechnology - Category: Microbiology Source Type: research