SUBMERGED CITRIC ACID FERMENTATION OF SUGAR BEET MOLASSES: EFFECT OF PRESSURE AND RECIRCULATION OF OXYGEN

Abstract

Recirculation of oxygen during submerged citric acid fermentation of ferrocyanide-treated beet molasses by Aspergillus niger was successful. Results obtained in 36-liter glass tower fermenters showed that neither rate of production nor total yield of citric acid was affected. No treatment of the recirculated gas other than carbon dioxide removal was required. At both low and high oxygen flow rates, increased oxygen pressure (up to 1.7 atm) markedly increased initial rate of production and total yield of citric acid. Oxygen pressure above 1.7 atm decreased citric acid yield. Within the limits tested, the effect of oxygen pressure was independent of total pressure.