A novel wheat arabino-xylanase from Trichoderma gamsii: Study on biochemical characterization, substrate recognition mechanism and its application in wheat flour dough and Chinese bread

A novel wheat arabino-xylanase gene, designated TgXyn11A , was isolated from T. gamsii and expressed in E. coli . TgXyn11A had a high specific activity of 153.87 U/mg towards wheat arabinoxylan. TgXyn11A exhibited peak activity at pH of 6.5 and temperature of 50 °C. Based on structural superposition, TgXyn11A could recognize FAX3, while Arg155 and Asn157 bound to the arabinose and ferulic acid side chains via hydrogen bonding, respectively. With the addition of 0–4 mg/kg TgXyn11A in the wheat dough making process, the viscoelasticity experiment showed that the strength and resistance to deformation of dough were improved. The Mixolab results suggesting the dough quality and shelf life could be improved by TgXyn11A. The enzyme (0–5 mg/kg) was applicated in the Chinese bread, the specific volume and hardness were improved significantly. Compared to the control, the specific volume of Chinese bread increased by 17.76% and the hardness decreased by 27.88% at 4 mg/kg of enzyme addition. Here, with addition of 4 mg/kg TgXyn11A, following 2 and 4 days of storage, the hardness of Chinese bread decreased by 21.48% and 66.93%, respectively. Thus, TgXyn11A could delay the aging phenomenon effectively. This study provided a potential wheat arabinoxylanase for application in the improvement of dough products. • A novel xylanase gene from T. gamsii was cloned and expressed in E. coli. • The enzyme was optimal at 50 °C, and showed 153.87 U/mg towards wheat arabinoxylan. • TgXyn11A structure could recognize FAX3, Arg155 and Asn157 were key residues bound to side chain. • TgXyn11A enhanced dough properties by reducing formation time, stability, weakening degree, and elasticity. • TgXyn11A could improve the softness and delay aging of flour products.