Abstract
Most microbial species, including model eukaryote Saccharomyces cerevisiae, possess genetic capability to utilize many alternative nutrient sources. Yet, it remains an open question whether these manifest into assimilatory phenotypes. Despite possessing all necessary pathways, S. cerevisiae grows poorly or not at all when glycerol is the sole carbon source. Here we discover, through multiple evolved lineages, genetic determinants underlying glycerol catabolism and the associated fitness trade-offs. Most evolved lineages adapted through mutations in the HOG pathway, but showed hampered osmotolerance. In the other lineages, we find that only three mutations cause the improved phenotype. One of these contributes counter-intuitively by decoupling the TCA cycle from oxidative phosphorylation, and thereby hampers ethanol utilization. Transcriptomics, proteomics and metabolomics analysis of the re-engineered strains affirmed the causality of the three mutations at molecular level. Introduction of these mutations resulted in improved glycerol utilization also in industrial strains. Our findings not only have a direct relevance for improving glycerol-based bioprocesses, but also illustrate how a metabolic pathway can remain unexploited due to fitness trade-offs in other, ecologically important, traits.
Original language | English |
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Pages (from-to) | 73-82 |
Journal | Metabolic Engineering |
Volume | 47 |
DOIs | |
Publication status | Published - May 2018 |
MoE publication type | A1 Journal article-refereed |
Funding
This work was sponsored by the Novo Nordisk Foundation, the German Ministry of Education and Research (BMBF, Grant no. 031A343A), and The Danish Agency for Science, Technology and Innovation (DASTI) (3039-00003B INNOFOND_SP) as part of the ERA-IB project “DeYeastLibrary”. Funding for A.M.F. and E.T.M. was provided by The Novo Nordisk Foundation Grant nos. NNF14OC0011269 and NNF10CC1016517.
Keywords
- Adaptive laboratory evolution
- Causal mutations
- Multi-omics analysis