Xiong Liang, Wang Ya-Ting, Zhou Ming-Hai, Takagi Hiroshi, Qin Jiufu, Zhao Xin-Qing
School of Life Science and Biotechnology, Dalian University of Technology, Dalian, 116024, China.
State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Science, and School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, China.
Synth Syst Biotechnol. 2024 May 29;9(4):723-732. doi: 10.1016/j.synbio.2024.05.013. eCollection 2024 Dec.
Acetic acid is a common inhibitor present in lignocellulose hydrolysate, which inhibits the ethanol production by yeast strains. Therefore, the cellulosic ethanol industry requires yeast strains that can tolerate acetic acid stress. Here we demonstrate that overexpressing a yeast native arginase-encoding gene, , renders acetic acid tolerance. Specifically, ethanol yield increased by 27.3% in the -overexpressing strain compared to the control strain under 5.0 g/L acetic acid stress. The global intracellular amino acid level and compositions were further analyzed, and we found that overexpression reduced the total amino acid content in response to acetic acid stress. Moreover, the overexpressing strain showed increased ATP level and improved cell membrane integrity. Notably, we demonstrated that the effect of overexpression was independent of the spermidine and proline metabolism, which indicates novel mechanisms for enhancing yeast stress tolerance. Our studies also suggest that is a novel genetic element to be used in synthetic biology of yeast for efficient production of fuel ethanol.
乙酸是木质纤维素水解产物中存在的一种常见抑制剂，它会抑制酵母菌株生产乙醇。因此，纤维素乙醇产业需要能够耐受乙酸胁迫的酵母菌株。在此我们证明，过表达酵母天然的精氨酸酶编码基因可使酵母具备乙酸耐受性。具体而言，在5.0 g/L乙酸胁迫下，与对照菌株相比，过表达该基因的菌株乙醇产量提高了27.3%。我们进一步分析了细胞内整体氨基酸水平和组成，发现该基因的过表达会降低乙酸胁迫下的总氨基酸含量。此外，过表达该基因的菌株ATP水平升高，细胞膜完整性得到改善。值得注意的是，我们证明该基因过表达的效果与亚精胺和脯氨酸代谢无关，这表明存在增强酵母胁迫耐受性的新机制。我们的研究还表明，该基因是酵母合成生物学中用于高效生产燃料乙醇的一种新型遗传元件。
