| Autor: |
Fei Liu, Junping Zhou, Mengkai Hu, Yan Chen, Jin Han, Xuewei Pan, Jiajia You, Meijuan Xu, Taowei Yang, Minglong Shao, Xian Zhang, Zhiming Rao |
| Jazyk: |
angličtina |
| Rok vydání: |
2023 |
| Předmět: |
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| Zdroj: |
Biotechnology for Biofuels and Bioproducts, Vol 16, Iss 1, Pp 1-14 (2023) |
| Druh dokumentu: |
article |
| ISSN: |
2731-3654 |
| DOI: |
10.1186/s13068-023-02258-7 |
| Popis: |
Abstract Background (R)-mandelic acid (R-MA) is a highly valuable hydroxyl acid in the pharmaceutical industry. However, biosynthesis of optically pure R-MA remains significant challenges, including the lack of suitable catalysts and high toxicity to host strains. Adaptive laboratory evolution (ALE) was a promising and powerful strategy to obtain specially evolved strains. Results Herein, we report a new cell factory of the Gluconobacter oxydans to biocatalytic styrene oxide into R-MA by utilizing the G. oxydans endogenous efficiently incomplete oxidization and the epoxide hydrolase (SpEH) heterologous expressed in G. oxydans. With a new screened strong endogenous promoter P 12780 , the production of R-MA was improved to 10.26 g/L compared to 7.36 g/L of using P lac . As R-MA showed great inhibition for the reaction and toxicity to cell growth, adaptive laboratory evolution (ALE) strategy was introduced to improve the cellular R-MA tolerance. The adapted strain that can tolerate 6 g/L R-MA was isolated (named G. oxydans STA), while the wild-type strain cannot grow under this stress. The conversion rate was increased from 0.366 g/L/h of wild type to 0.703 g/L/h by the recombinant STA, and the final R-MA titer reached 14.06 g/L. Whole-genome sequencing revealed multiple gene-mutations in STA, in combination with transcriptome analysis under R-MA stress condition, we identified five critical genes that were associated with R-MA tolerance, among which AcrA overexpression could further improve R-MA titer to 15.70 g/L, the highest titer reported from bulk styrene oxide substrate. Conclusions The microbial engineering with systematic combination of static regulation, ALE, and transcriptome analysis strategy provides valuable solutions for high-efficient chemical biosynthesis, and our evolved G. oxydans would be better to serve as a chassis cell for hydroxyl acid production. |
| Databáze: |
Directory of Open Access Journals |
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