FACTORS AFFECTING LACTIC-ACID PRODUCTION-RATE IN THE BUILT-IN ELECTRODIALYSIS FERMENTATION, AN APPROACH TO HIGH-SPEED BATCH CULTURE

To avoid cells adhering to the ion-exchange membrane and damage of the cells in electrodialysis fermentation (ED-F), ED-F with a microfiltration (MF) module, was used in lactate fermentation. In this system, after 38 h of cultivation, the dry cell weight (2.89 g/l) and the number of viable cells (4.8 x 10(9)/ml) were about 1.8 and 1.6 times more than those of the control fermentation, respectively. Lactate dehydrogenase activity in this system was maintained at a high level, resulting in reduction of fermentation time to complete batch culture within 38 h. From these results, ED-F with an MF module enabled high speed batch culture.