Enhanaced Propionic Acid Production by Mixed Culture of Propionibacterium acidipropioniai and Saccharomyces cerevisiae

In a batch mixed culture of Propionibacterium acidipropioniai and Saccharomyces cerevisiae, which could exploit synergistic effects, cell growth and propionic acid production rates of P. acidipropioniai significantly increased, compared with those in pure cultures. Compared with a pure culture, the mixed culture had a significant improvement on the maximal propionic acid (12.1 g/l vs. 10.1 g/l) and glycerol conversion efficiency (60.5% vs. 50.5%). Propionic acid production was further enhanced by an addition of glycerol solution in the fed-batch mixed culture; and the maximal propionic acid yield and glycerol conversion efficiency reached 27.9 g/l and 56.7%, respectively. These results showed that a mixed culture of P. acidipropionici and S. cerevisiae could serve as an excellent alternative to conventional propionic acid fermentation.