Separation of ethanol during its production by fermentation using a silicone rubber hollow fiber membrane module

Abstract

Monosaccharides form the basis of more complex sugars. Sucrose consists of a fructose molecule linked to a glucose molecule. Both glucose and fructose are readily fermentable by brewers yeast. In this study, a mutant of Saccharomyces cerevisiae was used for the co-production of fructose and ethanol by selectively converting glucose to ethanol from a sucrose medium. To enhance the fermentation process, a pervaporation unit was coupled to the bioreactor to keep the ethanol concentration in the broth at a low level, thereby reducing the ethanol inhibition on the yeast. The membrane module consisted of silicone rubber hollow fibers assembled in an inside feed/outside vacuum module design. Various experiments changing the time at which pervaporation was started were carried out (after 6 hrs, 3hrs and 0hrs), to examine its effects on the ethanol, fructose, biomass yields, ethanol productivity rates and the time required to complete the fermentation. Certain experiments were carried out by changing the flow rate through the membrane module. Two different membrane modules (different in area) were used for the co-production of fructose and ethanol. (Abstract shortened by UMI.)