Enhanced Ribonucleic Acid Production by High-Throughput Screening Based on Fluorescence Activation and Transcriptomic-Guided Fermentation Optimization in Saccharomyces cerevisiae

Abstract

Currently, the primary source of ribonucleic acids (RNAs), which is used as a flavor enhancer and nutritional supplement in the food manufacturing and processing industries, for large-scale industrial production is yeast, where the challenge is to optimize the cellular RNA content. Here, we developed and screened yeast strains yielding abundant RNAs via various methods. The novel Saccharomyces cerevisiae strain H1 with a 45.1% higher cellular RNA content than its FX-2 parent was successfully generated. Comparative transcriptomic analysis elucidated the molecular mechanisms underlying RNA accumulation in H1. Upregulation of genes encoding the hexose monophosphate and sulfur-containing amino acid biosynthesis pathways promoted RNA accumulation in the yeast, particularly in the presence of glucose as the sole carbon source. Feeding methionine into the bioreactor resulted in 145.2 mg/g dry cell weight and 9.6 g/L of cellular RNA content, which is the highest volumetric productivity of RNAs achieved in S. cerevisiae. This strategy of breeding S. cerevisiae strain with a higher capacity of accumulating abundant RNAs did not employ any genetic modification and thus will be favored by the food industry.

Promoting Nucleic Acid Synthesis in Saccharomyces cerevisiae through Enhanced Expression of Rrn7p, Rrn11p, IMPDH, and Pho84p

“…In line with our findings, Wu et al utilized 6-azauracil, an inhibitor of IMPDH, to drive the adaptive evolution of cells mutated by ethylmethanesulfonate. This approach led to a significant 42.6% increase in RNA content . Therefore, the activation of IMPDH expression emerges as an effective strategy for promoting RNA accumulation in S.…”

Combining Metabolic Engineering and Lipid Droplet Assembly to Achieve Campesterol Overproduction in Saccharomyces cerevisiae

“…40−42 The biggest advantage of high-density fermentation is that each parameter value can be finely controlled during the fermentation process to maintain optimal fermentation conditions for cell growth and the production of the target product. 43,44 On the one hand, the productivity of the final product can be maximized, and on the other hand, the volume of the fermentation tank can be fully utilized and separation costs can be reduced. 45,46 In the present study, due to the knockout of the ERG5 gene, the synthesis pathway of ergosterol in S. cerevisiae has been disrupted.…”