QuiescentFactory · Increasing metabolic engineering efficiency using a conditionally quiescent fission yeast mutant

The proposed project aims to solve a major challenge in metabolic engineering. In microbial metabolic engineering platforms, consumed nutrients are primarily invested into population growth instead of the production of chemicals of interest. Our team is studying a temperature-sensitive mutant of fission yeast (Schizosaccharomyces pombe), which grows normally at 26°C, but enters quiescence at 36°C, while at the same time maintaining its metabolic activity. Such an engineering platform could represent the holy grail of the metabolic engineering field - a chassis strain that can stop growing but keeps producing metabolites. Application of such pseudo-quiescent strain would be useful to both industrial and academic players. To develop this mutant into a new metabolic engineering chassis, I will first design a molecular cloning toolkit to perform metabolic engineering in S. pombe, which will enable construction and expression of complex biosynthetic pathways. Second, I will characterize the phenotype of the pseudoquiescent S. pombe mutant using a multi-omics approach. I will generate knowledge about mRNA, protein, metabolite and flux dynamics to delineate a genome-scale metabolic model of the chassis under pseudo-quiescence. Then, I will assess the ability of the S. pombe mutant to overproduce 3 different high-value compounds (kavain via phenylalanine, theophylline via purine and artemisinin precursor via mevalonate). Finally, I intend to reproduce the pseudo-quiescent mutant phenotype in other commonly used yeast species (Saccharomyces cerevisiae and Yarrowia lipolytica). In the short term, this research will deliver a new type of a metabolic engineering chassis for the production of complex chemicals to the metabolic engineering community. In the long term, it will contribute to the development of metabolic engineering as a competitive alternative of total synthesis of chemicals, leading to greener and renewable chemical industry.