Natural co-consumption of glucose and formic acid in Yarrowia lipolytica W29 in batch shake-flask cultures
To investigate the innate ability of Yarrowia lipolytica to co-consume glucose and formic acid, strain W29 was inoculated in synthetic medium with glucose with and without formic acid. S. cerevisiae strains CEN.PK113-7D (FDH1 , FDH2 ) and the formate dehydrogenase (FDH) double knockout strain CEN.PK556-7B (fdh1∆fdh2∆ ) were also tested in medium with glucose and formic acid as positive and negative control, respectively (Figure 2).
Within 24h, glucose was depleted in all cultures and in the culture of W29 the formic acid concentration decreased by 9.7 ± 0.2 mM compared to 4.5 ± 0.1 mM for CEN.PK113-7D. In contrast, the decrease in formic acid in the culture of CEN.PK556-7B (1.2 ± 0.0 mM) was comparable to what was observed in a sterile culture (1.1 ± 0.0 mM). Strikingly, the optical density after 24h was higher for the W29 culture with added formic acid (22.3 ± 0.6) than the culture with glucose only (20.3 ± 0.8), consistent with dissimilation of formic acid in this organism providing additional metabolic energy (ATP).