UP-FLOW ATTACHED-BED BIOREACTOR FOR CONTINUOUS ETHANOL FERMENTATION

Ethanol fermentation was carried out in an up-flow attached-bed (UFAB) continuous fermentor using different microorganisms, substrates, and attachement supports. When Saccharomyces fragilis was attached to cellulose acetate to ferment deproteinized and concentrated acid whey, ethanol productivity as high as 6.9 g/(L.h), 10 times that of a batch reactor, was obtained in a continuous UFAB bioreactor. When Zymomonas mobilis was attached to vermiculite in a continuous UFAB bioreactor to ferment a 10% glucose feed, ethanol productivity as high as 105.7 g/(L.h) was achieved with a dilution rate of 3.6 h-1 and an ethanol concentration of 29.0 g/L.