Abstract

The present work describes an approach that uses a reduction in biomass accumulation during fermentation to improve the properties of a strain producing L-threonine. Glutamyl- and glutaminyl-tRNA synthetases were chosen as targets. Mutants carrying temperature-sensitive alleles of the mentioned enzymes were obtained. It was shown with this system that suppression of the function of tRNA synthetases led to the rapid arrest of culture growth and an increase in the productivity and conversion of L-threonine synthesis. One of the temperature-sensitive strains was used to obtain mutants with the ts phenotype under nonpermissive conditions. Some of these mutants accumulated less biomass and produced 10–12% more threonine than the original strain.

中文翻译：

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谷氨酰胺和谷氨酰胺基-tRNA合成酶是设计生产L-苏氨酸的菌株的有前途的目标。

摘要

本工作描述了一种方法，该方法利用发酵过程中生物量积累的减少来改善产生L-苏氨酸的菌株的特性。选择谷氨酰胺和谷氨酰胺-tRNA合成酶作为靶标。获得了携带所述酶的温度敏感等位基因的突变体。用该系统显示出，tRNA合成酶功能的抑制导致培养物生长的迅速停止以及L-苏氨酸合成的生产率和转化率的增加。温度敏感菌株之一用于在非允许条件下获得具有ts表型的突变体。这些突变体中的一些积累的生物量比原始菌株少，并且苏氨酸的产量高出10–12％。