The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, Hangzhou, P.R.China.
Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, P.R.China.
J Appl Microbiol. 2021 Jun;130(6):1960-1971. doi: 10.1111/jam.14884. Epub 2020 Nov 9.
Constructing a strain with high yield of O-succinyl-l-homoserine (OSH) and improving the titre through multilevel fermentation optimization.
OSH high-yielding strain was first constructed by deleting the thrB gene to block the threonine biosynthesis. Single-factor experiment was carried out, where a Plackett-Burman design was used to screen out three factors (glucose, yeast and threonine) from the original 11 factors that affected the titre of OSH. The Box-Behnken response surface method was used to optimize the fermentation conditions. Through gene editing and medium optimization, the titre of OSH increased from 7·20 to 8·70 g l in 500 ml flask. Furthermore, the fermentation process and fed-batch fermentation conditions including pH, temperature, feeding strategy and feeding medium were investigated and optimized. Under the optimal conditions, the titre of OSH reached 102·5 g l , which is 5·6 times higher than before (15·6 g l ).
O-succinyl-l-homoserine fermentation process was established and the combination of response surface methodology and metabolic pathway analysis effectively improved the titre of OSH.
In this study, the titre of OSH reached the needs for industrial production and the metabolic pathway of OSH was demonstrated for further optimization.
构建一种 O-琥珀酰-L-高丝氨酸（OSH）高产菌株，并通过多级发酵优化提高产量。
首先通过删除 thrB 基因来阻断苏氨酸生物合成，构建 OSH 高产菌株。进行单因素实验，其中 Plackett-Burman 设计用于从最初的 11 个影响 OSH 产量的因素中筛选出三个因素（葡萄糖、酵母和苏氨酸）。采用 Box-Behnken 响应面法优化发酵条件。通过基因编辑和培养基优化，OSH 的产量从 500ml 摇瓶中的 7.20g/L 提高到 8.70g/L。此外，还研究和优化了发酵过程和分批补料发酵条件，包括 pH 值、温度、补料策略和补料培养基。在最佳条件下，OSH 的产量达到 102.5g/L，比之前提高了 5.6 倍（15.6g/L）。
建立了 OSH 发酵工艺，通过响应面法和代谢途径分析的结合，有效地提高了 OSH 的产量。
在这项研究中，OSH 的产量达到了工业生产的需求，并展示了 OSH 的代谢途径，以进一步进行优化。
