Optimization and scale-up of propionic acid production by propionic acid-tolerant Propionibacterium acidipropionici with glycerol as the carbon source

Propionic acid production by Propionibacterium acidipropionici with glycerol as sole carbon source was studied in 7-L batch and 10 m3 bioreactor cultures. In batch cultures, propionic acid production increased and specific cell growth rate decreased with increasing glycerol concentrations. Maximum propionic acid production and productivity reached 44.62 ± 1.12 g/L and 0.20 ± 0.0075 g L−1 h−1at 220 h, respectively, when glycerol was fed at a constant rate of 0.01 L/h from 72 to 120 h with an initial glycerol concentration of 30 g/L. In the 10 m3 bioreactor, maximum propionic acid production reached 47.28 ± 0.12 g/L at 240 h. This glycerol feeding approach may be useful for propionic acid production on an industrial scale.