Lactic acid production in electrodialysis culture.

The rate of lactic acid production by Lactobacillus delbrueckii strain YPX was greatly improved by converting the acid to Na-lactate and continuously removing the salt from the fermentation broth with an electrodialyzer. The fermentation using glucose (85gl-1) as a raw material was completed in 9.9h and the lactic acid concentration in the permeate compartment reached 90gl-1. The average production rate was 8.7gl-1 h-1, which was 12 times higher than that of the fermentation with direct electrodialysis of the lactic acid produced. The phosphate ions in the culture broth were electrodialyzed simultaneously with the lactate ions which caused a decrease in the fermentation rate in some cases.