A novel thermostable β-1, 3-1, 4-glucanase from Thermoascus aurantiacus and its application in oligosaccharide production from oat bran. (November 2018)

• Record Type: Journal Article
• Authors: Yan, Qaojuan; Yang, Hongye; Jiang, Zhengqiang; Liu, Erwei; Yang, Shaoqing
• Is Part Of: Carbohydrate research. Volume 469(2018)
• Page Start: 31
• Page End: 37
• Publication Date: 2018-11
• Subjects: β-1, 3-1, 4-Glucanase -- Thermoascus aurantiacus -- Characterization -- Oligosaccharide -- Oat bran; Carbohydrates -- Periodicals; Chemistry, Organic -- Periodicals; Biochemistry -- Periodicals; Carbohydrates -- Periodicals; Chimie organique -- Périodiques; Glucides -- Périodiques; Biochemistry; Carbohydrates; Chemistry, Organic; Periodicals; Electronic journals; 507.78
• DOI: 10.1016/j.carres.2018.08.017
• Languages: English
• ISSNs: 0008-6215

Abstract

Abstract: Fermentation conditions for β-1, 3-1, 4-glucanase (TaGlu34) production in submerged culture by a thermophilic fungus, Thermoascus aurantiacus CAU830 were optimized. The highest enzyme activity of 3741 U/mL was obtained, and the crude enzyme was purified to homogeneity with a purification fold of 7.3 and a recovery yield of 11.6%. The molecular mass of the purified enzyme was estimated to be approximately 34 kDa on SDS-PAGE. TaGlu34 was most active at pH 6.0 and 75 °C, respectively. It showed excellent thermostability with thermal denaturing half-lives of 209, 130 and 69 min at 50, 60 and 70 °C, respectively. TaGlu34 exhibited strict substrate specificity towards barley β-glucan (13, 527 U/mg), oat β-glucan (12, 502 U/mg) and lichenan (9225 U/mg), but displayed no activity on other tested polysaccharides including laminarin, xylan, pullulan, CMC and starch. TaGlu34 hydrolyzed barley β-glucan and lichenan to yield both mainly disaccharide and trisaccharide, suggesting that it should be an endo type β-1, 3-1, 4-glucanase. Furthermore, TaGlu34 efficiently degraded the β-glucan component in oat bran to produce mainly oligosaccharides with degrees of polymerization (DP) 3–5, with the highest conversion ratio of 47.1%. The high yield and excellent enzymatic properties of TaGlu34 may make it a good candidate in industries. Graphical abstract: Highlights: A thermostable β-1, 3-1, 4-glucanase (TaGlu34) was purified and characterized. TaGlu34 was most active at pH 6.0 and 75 °C and stable up to 70 °C. TaGlu34 exhibited strict specificity on barley β-glucan, oat β-glucan and lichenan. TaGlu34 degraded oat bran β-glucan to produce oligosaccharides with yield of 47.1%.