The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800# Lihu Road, WuXi, 214122, People's Republic of China.
State Key Laboratory of Food Science and Technology, School of Biotechnology, Jiangnan University, 1800# Lihu Road, WuXi, 214122, People's Republic of China.
Appl Microbiol Biotechnol. 2022 Jan;106(1):145-160. doi: 10.1007/s00253-021-11714-z. Epub 2021 Dec 6.
This article focuses on engineering Corynebacterium glutamicum to produce L-lysine efficiently from starch using combined method of "classical breeding" and "genome breeding." Firstly, a thermo-tolerable L-lysine-producing C. glutamicum strain KT was obtained after multi-round of acclimatization at high temperature. Then, amylolytic enzymes were introduced into strain KT, and the resultant strains could use starch for cell growth and L-lysine production except the strain with expression of isoamylase. In addition, co-expression of amylolytic enzymes showed a good performance in starch degradation, cell growth and L-lysine production, especially co-expression of α-amylase (AA) and glucoamylase (GA). Moreover, L-lysine yield was increased by introducing AA-GA fusion protein (i.e., strain KTS-5), and finally reached to 23.9 ± 2.3 g/L in CgXIIM-medium. It is the first report of an engineered L-lysine-producing strain with maximum starch utilization that may be used as workhorse for producing amino acid using starch as the main feedstock. KEY POINTS: • Thermo-tolerable C. glutamicum was obtained by temperature-induced adaptive evolution. • The fusion order between AA and GA affects the utilization efficiency of starch. • C. glutamicum with starch utilization was constructed by optimizing amylases expression.
本文专注于通过“经典育种”和“基因组育种”相结合的方法，对谷氨酸棒杆菌进行工程改造，以有效地从淀粉生产 L-赖氨酸。首先，经过多轮高温驯化，获得了一种耐热的 L-赖氨酸生产谷氨酸棒杆菌 KT 菌株。然后，向菌株 KT 中引入了淀粉分解酶，结果发现除了表达异淀粉酶的菌株外，其他菌株都可以利用淀粉进行细胞生长和 L-赖氨酸生产。此外，淀粉分解酶的共表达在淀粉降解、细胞生长和 L-赖氨酸生产方面表现出良好的性能，尤其是α-淀粉酶（AA）和糖化酶（GA）的共表达。此外，通过引入 AA-GA 融合蛋白（即菌株 KTS-5），提高了 L-赖氨酸的产量，最终在 CgXIIM 培养基中达到 23.9 ± 2.3 g/L。这是首例报道的可最大程度利用淀粉的工程化 L-赖氨酸生产菌株，它可能成为使用淀粉作为主要原料生产氨基酸的生产菌株。 关键点： • 通过温度诱导适应性进化获得了耐热的谷氨酸棒杆菌。 • AA 和 GA 之间的融合顺序影响淀粉的利用效率。 • 通过优化淀粉酶的表达构建了可利用淀粉的谷氨酸棒杆菌。
