Ye Huimin, DU Jun, Tang Yujing, Yuan Xin, Zhang Zheng, Li Lu, Ji Yizhi
Beijing Key Laboratory of Biomass Waste Resource Utilization, College of Biochemical Engineering, Beijing Union University, Beijing 100023, China.
Research Institute, Beijing Tsingke Biotech Co., Ltd., Beijing 100000, China.
Sheng Wu Gong Cheng Xue Bao. 2024 Sep 25;40(9):3201-3215. doi: 10.13345/j.cjb.240177.
L-tryptophan is an indispensable essential amino acid with a wide range of applications, which leads to a high demand. Accordingly, the production of L-tryptophan becomes a much-anticipated direction in research and industrial development. While irrational mutagenesis is an effective means to breed industrial strains, how to screen the strains with desirable phenotypes is still a major challenge. In order to improve the efficiency and accuracy of screening L-tryptophan high-yield strains, we used atmospheric and room temperature plasma mutagenesis to construct a random mutant library and then combined it with high-throughput screening in deep-well plates. Using a pseudo-fluorescent protein sensor capable of responding specifically to L-tryptophan, we successfully screened out a strain producing L-tryptophan at a high yield from a random mutagenesis library. The fermentation with the strain in shake flasks produced L-tryptophan at a yield of 1.99 g/L, which was 41.77% higher than that of the starting strain. Finally, the mechanism of high yield of the strain was deciphered by comparative genomics and transcriptomics. The above strategies provide a solid research foundation for further selection and development of high quality L-tryptophan producing strains.
L-色氨酸是一种不可或缺的必需氨基酸，应用广泛，需求量大。因此，L-色氨酸的生产成为研究和产业发展中备受期待的方向。虽然非理性诱变是培育工业菌株的有效手段，但如何筛选出具有理想表型的菌株仍是一项重大挑战。为了提高筛选L-色氨酸高产菌株的效率和准确性，我们利用常压室温等离子体诱变构建了一个随机突变体文库，然后将其与深孔板中的高通量筛选相结合。使用一种能够特异性响应L-色氨酸的假荧光蛋白传感器，我们成功地从随机诱变文库中筛选出一株高产L-色氨酸的菌株。该菌株在摇瓶中发酵产L-色氨酸的产量为1.99 g/L，比出发菌株高出41.77%。最后，通过比较基因组学和转录组学解析了该菌株高产的机制。上述策略为进一步选育和开发优质L-色氨酸生产菌株提供了坚实的研究基础。
