Engineering the C4 pathway of Corynebacterium glutamicum for efficient production of 5-aminolevulinic acid.

Lijun Wang; Sihan Yan; Taowei Yang; Meijuan XU; Xian Zhang; Minglong Shao; Huazhong LI; Zhiming Rao

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Engineering the C4 pathway of Corynebacterium glutamicum for efficient production of 5-aminolevulinic acid.

Author: Lijun WANG ¹ ; Sihan YAN ¹ ; Taowei YANG ¹ ; Meijuan XU ¹ ; Xian ZHANG ¹ ; Minglong SHAO ¹ ; Huazhong LI ¹ ; Zhiming RAO ¹
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1. Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China.
Publication Type:Journal Article
Keywords: 5-aminolevulinic acid; C4 pathway; Corynebacterium glutamicum; metabolic engineering
MeSH: Aminolevulinic Acid/metabolism*; Corynebacterium glutamicum/metabolism*; Fermentation; Metabolic Engineering; Rhodobacter capsulatus/enzymology*; Rhodopseudomonas/enzymology*
From: Chinese Journal of Biotechnology 2021;37(12):4314-4328
CountryChina
Language:Chinese
Abstract: 5-aminolevulinic acid (5-ALA) plays an important role in the fields of medicine and agriculture. 5-ALA can be produced by engineered Escherichia coli and Corynebacterium glutamicum. We systematically engineered the C4 metabolic pathway of C. glutamicum to further improve its ability to produce 5-ALA. Firstly, the hemA gene encoding 5-ALA synthase (ALAS) from Rhodobacter capsulatus and Rhodopseudomonas palustris were heterologously expressed in C. glutamicum, respectively. The RphemA gene of R. palustris which showed relatively high enzyme activity was selected. Screening of the optimal ribosome binding site sequence RBS5 significantly increased the activity of RphemA. The ALAS activity of the recombinant strain reached (221.87±3.10) U/mg and 5-ALA production increased by 14.3%. Subsequently, knocking out genes encoding α-ketoglutarate dehydrogenase inhibitor protein (odhI) and succinate dehydrogenase (sdhA) increased the flux of succinyl CoA towards the production of 5-ALA. Moreover, inhibiting the expression of hemB by means of sRNA reduced the degradation of 5-ALA, while overexpressing the cysteine/O-acetylserine transporter eamA increased the output efficiency of intracellular 5-ALA. Shake flask fermentation using the engineered strain C. glutamicum 13032/∆odhI/∆sdhA-sRNAhemB- RBS5RphemA-eamA resulted in a yield of 11.90 g/L, which was 57% higher than that of the original strain. Fed-batch fermentation using the engineered strain in a 5 L fermenter produced 25.05 g/L of 5-ALA within 48 h, which is the highest reported-to-date yield of 5-ALA from glucose.