Niu Kun, Mei Zilong, Guan Anqi, Cai Wenbin, Chen Maoqin, Liu Zhiqiang, Zheng Yuguo
College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China.
Sheng Wu Gong Cheng Xue Bao. 2024 Mar 25;40(3):895-907. doi: 10.13345/j.cjb.230388.
As the only essential amino acid containing elemental sulphur, L-methionine has important physiological and biochemical functions in living organisms. However, the fermentative production of L-methionine has not met the requirements of industrial production because of its low production level. In this paper, the fermentation process of an efficient L-methionine producing strain . W3110Δ/PAM constructed previously was systematically optimized. Based on the optimal initial glucose concentration, the effects of different fed-batch fermentation processes, including DO-Stat, pH-Stat, controlling residual sugar control at different level and feeding glucose with constant rate, on L-methionine fermentation were studied. It was found that the control of glucose concentration greatly affected the fermentation process. Subsequently, an optimal fed-batch fermentation process was developed, where the L-methionine titer was increased to 31.71 g/L, the highest yield reported to date, while the fermentation time was shortened to 68 h. Meanwhile, a fermentation kinetics model under the optimal fed-batch fermentation conditions was established, which fitted well with the biosynthesis process of L-methionine. This study may facilitate further development of the fermentative production of L-methionine.
作为唯一含元素硫的必需氨基酸，L-甲硫氨酸在生物体内具有重要的生理和生化功能。然而，由于L-甲硫氨酸的发酵生产水平较低，尚未满足工业生产的需求。本文对前期构建的高效L-甲硫氨酸生产菌株W3110Δ/PAM的发酵过程进行了系统优化。基于最佳初始葡萄糖浓度，研究了不同补料分批发酵过程，包括溶氧控制、pH控制、不同水平的残糖控制以及恒速补加葡萄糖，对L-甲硫氨酸发酵的影响。结果发现，葡萄糖浓度的控制对发酵过程有很大影响。随后，开发了一种最佳补料分批发酵工艺，L-甲硫氨酸产量提高到31.71 g/L，这是迄今为止报道的最高产量，同时发酵时间缩短至68 h。同时，建立了最佳补料分批发酵条件下的发酵动力学模型，该模型与L-甲硫氨酸的生物合成过程拟合良好。本研究可能有助于L-甲硫氨酸发酵生产的进一步发展。
