NONCOMPETITIVE PRODUCT INHIBITION IN LACTIC-ACID FERMENTATION FROM GLUCOSE

A kinetic study regarding product inhibition in lactic acid fermentation by Streptococcus faecalis, which produces L-lactic acid, was performed in a chemostat at various feed concentrations of glucose (10, 20, and 30 g/1) at pH 7.0. Steady-state kinetic constants for the specific consumption rate of glucose and the specific production rate of lactic acid were determined at a residual glucose concentration below 2 g/l, which was accomplished in a chemostat. All the parameters, the specific growth rate, the specific consumption rate of glucose, and the specific production rate of lactic acid, were definitely related to non-competitive inhibition with regard to the concentration of the product, lactic acid.