Suástegui Miguel, Guo Weihua, Feng Xueyang, Shao Zengyi
Department of Chemical and Biological Engineering, Iowa State University, Ames, Iowa.
NSF Engineering Research Center for Biorenewable Chemicals (CBiRC), Ames, Iowa.
Biotechnol Bioeng. 2016 Dec;113(12):2676-2685. doi: 10.1002/bit.26037. Epub 2016 Jun 30.
Although Saccharomyces cerevisiae is the most highly domesticated yeast, strain dependency in biotechnological processes still remains as a common, yet poorly understood phenomenon. To investigate this, the entrance to the aromatic amino acid biosynthetic pathway was compared in four commonly used S. cerevisiae laboratory strains. The strains were engineered to accumulate shikimate by overexpressing a mutant version of the pentafunctional ARO1 enzyme with disrupted activity in the shikimate kinase subunit. Carbon tracing and C metabolic flux analysis combined with quantitative PCR, revealed that precursor availability and shikimate production were dramatically different in the four equally engineered strains, which were found to be correlated with the strains' capacity to deal with protein overexpression burden. By implementing a strain-dependent approach, the genetic platform was reformulated, leading to an increase in yield and titer in all strains. The highest producing strain, INVSc1-SA3, produced 358 mg L of shikimate with a yield of 17.9 mg g These results underline the importance of strain selection in developing biological manufacturing processes, demonstrate the first case of high production of shikimate in yeast, and provide an appropriate platform for strain selection for future production of aromatic compounds. Biotechnol. Bioeng. 2016;113: 2676-2685. © 2016 Wiley Periodicals, Inc.
尽管酿酒酵母是驯化程度最高的酵母,但生物技术过程中的菌株依赖性仍然是一种常见但却了解甚少的现象。为了对此进行研究,我们比较了四种常用的酿酒酵母实验室菌株中芳香族氨基酸生物合成途径的入口。通过过表达在莽草酸激酶亚基中活性被破坏的五功能ARO1酶的突变体,对这些菌株进行改造以积累莽草酸。碳追踪和C代谢通量分析结合定量PCR表明,在这四种经过相同改造的菌株中,前体可用性和莽草酸产量存在显著差异,且发现这与菌株应对蛋白质过表达负担的能力相关。通过采用依赖菌株的方法,对遗传平台进行了重新设计,从而使所有菌株的产量和滴度都有所提高。产量最高的菌株INVSc1-SA3产生了358 mg/L的莽草酸,产量为17.9 mg/g。这些结果强调了菌株选择在生物制造工艺开发中的重要性,证明了酵母中高产量莽草酸的首个案例,并为未来芳香族化合物生产的菌株选择提供了合适的平台。《生物技术与生物工程》2016年;113: 2676 - 2685。© 2016威利期刊公司