谷氨酸棒杆菌
脯氨酸
生物化学
脱氢酶
脯氨酸脱氢酶
发酵
磷酸戊糖途径
谷氨酸脱氢酶
基因
化学
氨基酸
生物
酶
糖酵解
谷氨酸受体
受体
作者
Jiao Zhang,Fenghui Qian,Feng Dong,Qingzhuo Wang,Jiacheng Sun,Yu Jiang,Sheng Yang
标识
DOI:10.1021/acssynbio.0c00249
摘要
l-Proline is an important amino acid that has various industrial applications. Industrial l-proline-producing strains are obtained by the mutagenesis of Corynebacterium glutamicum. In this study, the optimized C. glutamicum genome-editing tools were further applied in the de novo construction of a hyper-l-proline-producing strain. Overexpression of a feedback inhibition-resistant γ-glutamic kinase mutant ProBG149K, deletion of a proline dehydrogenase to block l-proline degradation, overexpression of glutamate dehydrogenase to increase glutamate synthesis flux, the mutation of 6-phosphate gluconate dehydrogenase and glucose-6-phosphate-dehydrogenase in the pentose phosphate pathway to enhance NADPH supply, the deletion of pyruvate aminotransferase to decrease the byproduct l-alanine synthesis, and weakening of α-ketoglutarate dehydrogenase to regulate the TCA cycle were combined to obtain ZQJY-9. ZQJY-9 produced 19.68 ± 0.22 g/L of l-proline in flask fermentation and was also demonstrated at the 3 L bioreactor level by fed-batch fermentation producing 120.18 g/L of l-proline at 76 h with the highest productivity of 1.581 g/L/h.
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