A simple illustration for possible roles of mutated proteins in the evolved Pdc negative strains. The blue solid arrows represent the reactions catalyzed by the enzymes, which are indicted in blue text. The blue dash line represents the transportation between different subcellular organelles. The black lines with a bar at one end represent the repression or inhibition. The red circles represent the block due to Pdc deletions. a Simplified acetyl-CoA metabolism in the parental Pdc negative strain. The PDH complex and TCA cycle enzymes is repressed by high glucose uptake via hexose transporters (HXT). b Simplified acetyl-CoA metabolism in evolved Pdc negative strain with point mutated Mth1 (Mth1*) and Cit1 (Cit1*). Glucose uptake via HXT decreases in the presence of Mth1*, resulting in derepression of the PDH complex and TCA cycle enzymes. Cit1* with predicted decreased activity allows more mitochondrial acetyl-CoA convert to acetate by Ach1, which can be transported to the cytosol and converted to acetyl-CoA there.