EFFECTS OF ETHANOL CONCENTRATION AND STRIPPING TEMPERATURE ON CONTINUOUS FERMENTATION RATE

The operation of a pilot plant consisting of a 14-1 fermenter, 10-cm p acked column and condenser for continuous fermentation and stripping o f ethanol was stable for more than 100 days. The feed consisted of a n on-sterile solution of 560 g/l glucose with 100 g/l corn steep water. Fouling of the packing in the column with attached growth of yeast cel ls was controlled by in situ washing at intervals of 3-6 days. A compu ter simulation of the pilot plant was developed and used to analyze th e data. The productivity of the continuous fermenter varied from 14 g ethanol to 17 g ethanol l(-1) h(-1). The yield was equal to the maximu m theoretically possible: 0.51 g ethanol/g glucose consumed. Results a re fit to linear models for the effects of ethanol concentration on sp ecific growth rate and cell yield, and for the effect of stripping tem perature on specific growth rate.