CONTINUOUS PROPIONIC-ACID FERMENTATION OF HYDROLYZED COD (GADUS-MORHUA) GURRY

Hydrolyzed cod gurry to which 4.0% glucose was added yielded a final p H of 4.5 after 96 h of incubation at 32C following inoculation with a 1.0% (v/v) inoculum (similar to 10(8) cells/mL) of a propionic acid pr oducing bacterial culture. The use of a 90% (v/v) inoculum still resul ted in a prolonged incubation time of 72 h to reach a pH of 4.5. A con tinuous propionic acid fermentation was successfully achieved for a pe riod of 18 days with the addition of 2.5% to 4.0% glucose and a nutrie nt feed rate of 30 mL/h using a 500 mL fermentation vessel. A constant pH of 4.5 with an accompanying propionic acid concentration of 1.4% w as maintained. Extrapolation of experimental data indicated that a glu cose concentration of 2.2% is optimum.