KINETICS OF SOLID-STATE ETHANOL FERMENTATION FROM APPLE POMACE

A kinetic study of solid-state ethanol fermentation of apple pomace was conducted using a horizontal batch reactor. McIntosh apple variety and the yeast Saccharomyces cerevisiae ATCC 24702 were used. As ethanol fermentation typically, exhibits product-associated kinetics, both cell growth and ethanol production were described with logistic functions and were related to glucose utilization. The estimated cell growth constant K ranged from 0.09 to 0.30 h-1 and the ethanol production constant K' varied from 0.07 to 0.16 h-1. Values of ethanol yield on glucose (Y(p/s)) ranged from 0.33 to 0.37, whereas ethanol yield on cell (Y(p/s)) during solid-state fermentation of apple pomace ranged from 2.6 x 10(-8) to 3.14 x 10(-8) g/colony-forming unit (cfu).