School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo, China.
School of Life Science, Taizhou University, Taizhou, China.
J Sci Food Agric. 2024 Dec;104(15):9617-9629. doi: 10.1002/jsfa.13786. Epub 2024 Aug 1.
Research on the co-production of multiple enzymes by Bacillus velezensis as a novel species is still a topic that needs to be studied. This study aimed to investigate the fermentation characteristics of B. velezensis D6 co-producing α-amylase and protease and to explore their enzymatic properties and applications in fermentation.
The maximum co-production of α-amylase and protease reached 13.13 ± 0.72 and 2106.63 ± 64.42 U mL, respectively, under the optimal fermented conditions (nutrients: 20.0 g L urea, 20.0 g L glucose, 0.7 g L MnCl; incubation conditions: initial pH 7.0, temperature 41 °C, 8% inoculation size and 30% working volume). Moreover, the genetic co-expression of α-amylase and protease increased from 0 to 24 h and then decreased after 36 h at the transcriptional level, which coincided with the growth trend of B. velezensis D6. The optimal reaction temperature of α-amylase was 55-60 °C, while that of protease was 35-40 °C. The activities of α-amylase and protease were retained by over 80% after thermal treatment (90 °C, 1 h), which indicated that two enzymes co-produced by B. velezensis D6 demonstrated excellent thermal stability. Moreover, the two enzymes were stable over a wide pH range (pH 4.0-8.0 for α-amylase; pH 4.0-9.0 for protease). Finally, the degrees of hydrolysis of corn, rice, sorghum and soybeans by α-amylase from B. velezensis D6 reached 44.95 ± 2.95%, 57.16 ± 2.75%, 52.53 ± 4.01% and 20.53 ± 2.42%, respectively, suggesting an excellent hydrolysis effect on starchy raw materials. The hydrolysis degrees of mackerel heads and soybeans by protease were 43.93 ± 2.19% and 26.38 ± 1.72%, respectively, which suggested that the protease from B. velezensis D6 preferentially hydrolyzed animal-based protein.
This is a systematic study on the co-production of α-amylase and protease by B. velezensis D6, which is crucial in widening the understanding of this species co-producing multi-enzymes and in exploring its potential application. © 2024 Society of Chemical Industry.
作为一个新物种，研究解淀粉芽孢杆菌同时生产多种酶的发酵特性仍然是一个需要研究的课题。本研究旨在探讨解淀粉芽孢杆菌 D6 同时生产α-淀粉酶和蛋白酶的发酵特性，并探索其在发酵中的酶学性质和应用。
在最佳发酵条件下（营养物：20.0 g/L 尿素、20.0 g/L 葡萄糖、0.7 g/L MnCl），α-淀粉酶和蛋白酶的最大协同产量分别达到 13.13±0.72 和 2106.63±64.42 U/mL。此外，在转录水平上，α-淀粉酶和蛋白酶的遗传协同表达从 0 增加到 24 h，然后在 36 h 后下降，这与解淀粉芽孢杆菌 D6 的生长趋势一致。α-淀粉酶的最适反应温度为 55-60°C，而蛋白酶的最适反应温度为 35-40°C。经热处理（90°C，1 h）后，α-淀粉酶和蛋白酶的活性保留率均超过 80%，表明解淀粉芽孢杆菌 D6 同时产生的两种酶具有优异的热稳定性。此外，两种酶在较宽的 pH 范围内稳定（α-淀粉酶的 pH 值为 4.0-8.0；蛋白酶的 pH 值为 4.0-9.0）。最后，解淀粉芽孢杆菌 D6 的α-淀粉酶对玉米、大米、高粱和大豆的水解度分别达到 44.95±2.95%、57.16±2.75%、52.53±4.01%和 20.53±2.42%，表明对淀粉原料具有良好的水解效果。蛋白酶对鲭鱼鱼头和大豆的水解度分别为 43.93±2.19%和 26.38±1.72%，表明解淀粉芽孢杆菌 D6 的蛋白酶优先水解动物蛋白。
这是对解淀粉芽孢杆菌 D6 同时生产α-淀粉酶和蛋白酶的系统研究，对于拓宽对该物种同时生产多种酶的认识和探索其潜在应用具有重要意义。
