Project description:Many toxins and stressors found in hydrolysates inhibit microbial metabolism and product formation, requiring mitigation strategies including strain engineering. To identify mechanisms of toxicity and targets for genetic engineering, we used a chemical genomics approach with a library of S. cerevisiae deletion mutants cultured anaerobically in dozens of individual compounds found in different types of hydrolysates, to explore shared and divergent gene requirements across inhibitors. Relationships in chemical-genomic profiles identified classes of toxins that provoked similar cellular responses, spanning inhibitor relationships that were not expected from chemical classification. Our results also revealed widespread antagonistic effects across inhibitors, such that the same gene deletions are beneficial for surviving some toxins but detrimental for others. As a proof of principle, we used the gene-deletion responses to single inhibitors to successfully predict strains whose fitness was improved in complex inhibitor mixes found in synthetic hydrolysates. We discuss the implications for strain engineering and the potential of this rich dataset for identifying engineering targets.