Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; Synergetic Innovation Center of Food Safety and Nutrition, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; Synergetic Innovation Center of Food Safety and Nutrition, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
Int J Biol Macromol. 2018 Feb;107(Pt A):28-34. doi: 10.1016/j.ijbiomac.2017.08.139. Epub 2017 Aug 30.
1,3-1,4-β-glucanase was an important biotechnological aid in the brewing industry. In a previous research, a Bacillus BglTO mutant (BglTO) with high tolerance towards high temperature and low-pH conditions was constructed and expressed in Escherichia coli. However, E. coli was not a suitable host for enzyme production in food industry. Therefore, the present work aimed to achieve the high-level expression of BglTO in Bacillus subtilis WB600 and to test its effect in Congress mashing. The β-glucanase mutant was successfully expressed in B. subtilis WB600 and favorable plasmid segregation and structural stability were observed. The maximal extracellular activity of β-glucanase in recombinant B. subtilis WB600 reached 4840.4UmL after cultivation condition optimization, which was 1.94-fold higher than that before optimization. The fermentation capacity of recombinant B. subtilis reached 242.02UmLh, which was the highest among all reported β-glucanases. The addition of BglTO in Congress mashing significantly reduced the filtration time and viscosity of mash by 29.7% and 12.3%, respectively, which was superior to two commercial enzymes. These favorable properties indicated that B. subtilis WB600 was a suitable host for production of BglTO, which was promising for application in the brewing industry.
1,3-1,4-β-葡聚糖酶是酿造工业中一种重要的生物技术辅助酶。在之前的研究中，构建并在大肠杆菌中表达了一种对高温和低 pH 条件具有高耐受性的芽孢杆菌 BglTO 突变体（BglTO）。然而，大肠杆菌并不是食品工业中酶生产的合适宿主。因此，本工作旨在实现 BglTO 在枯草芽孢杆菌 WB600 中的高水平表达，并测试其在糖化过程中的效果。β-葡聚糖酶突变体在枯草芽孢杆菌 WB600 中成功表达，并观察到有利的质粒分离和结构稳定性。通过培养条件优化，重组枯草芽孢杆菌 WB600 中β-葡聚糖酶的最大胞外酶活达到 4840.4UmL，比优化前提高了 1.94 倍。重组枯草芽孢杆菌的发酵能力达到 242.02UmLh，在所有报道的β-葡聚糖酶中最高。在糖化过程中添加 BglTO 可分别将过滤时间和麦芽汁黏度降低 29.7%和 12.3%，优于两种商业酶。这些优良特性表明，枯草芽孢杆菌 WB600 是生产 BglTO 的合适宿主，有望在酿造工业中得到应用。
