PRODUCTION OF SUCCINIC ACID BY ANAEROBIOSPIRILLUM-SUCCINICIPRODUCENS

The effect of an external supply of carbon dioxide and pH on the produ ction of succinic acid by Anaerobiospirillum succiniciproducens was st udied. In a rich medium containing yeast extract and peptone, when the external carbon dioxide supply was provided by a 1.5M 1 Na2CO3 soluti on that also was used to maintain the pH at 6.0, no additional carbon dioxide supply was needed. In fact, sparging CO2 gas into the fermente r at 0.025 L/L-min or higher rates resulted in significant decreases i n both production rate and yield of succinate. Under the same conditio ns, the production of the main by-product acetate was not affected by sparging CO2 gas into the fermenter. The optimum pH (pH 6.0) for the p roduction of succinic acid was found to be in agreement with results p reviously reported in the literature. Succinic acid production also wa s studied in an industrial-type inexpensive medium in which light stee p water was the only source of organic nutrients. At pH 6.0 and with a CO2 gas sparge rate of 0.08 L/L-min, succinate concentration reached a maximum of 32 g/L in 27 h with a yield of 0.99 g succinate/g glucose consumed.