<p>We introduced the lactate dehydrogenase gene (ldhA) regulated by a galactose promoter into yeast cells, induced it under different conditions, and measured the lactic acid content in the supernatant. We found that, aside from a small amount of leakage expression of the ldhA gene itself, galactose can very efficiently induce yeast to secrete sufficient lactic acid into the external environment. It is worth noting that because glucose is a better carbon source for yeast compared to galactose, the difference in carbon sources can have some effects on lactic acid secretion beyond just gene expression, which we have not demonstrated here. There is a more detailed discussion in the wet lab section.</p>
<pstyle="text-align: center; font-size: 0.9em; margin-top: 10px;">fig 2 Results of yeast-induced lactic acid secretion. This image shows the differences in lactic acid secretion by yeast induced by different carbon sources (glucose or galactose).(wt: wild-type yeast, ldhA: yeast transformed with a plasmid containing the ldhA gene)</p>
