EFFECT OF MEDIA SUPPLEMENTATION ON ETHANOL-PRODUCTION BY SIMULTANEOUSSACCHARIFICATION AND FERMENTATION PROCESS

In this study, fermentation tests on different initial glucose concent rations, ranging from 100 to 200 g/L, were conducted to identify the e thanol tolerance of Kluyveromyces marxianus EMS-26 strain at 42 degree s C. Lipid and nutrient additions to the fermentation medium were made in order to improve the ethanol production at 42 degrees C. The resul ts obtained showed that the addition of unsaturated fatty acids and st erols to the SSF media reduced hydrolysis yields and ethanol productio n as compared to tests carried out on controls without lipid supplemen tation. These results seem to indicate that cellulases performed bette r when no lipid supplementation was used. The decrease in the sacchari fication in the presence of 0.5% Tween 80 (10% decrease in the filter paper activity) seems to be closely related to the denaturation of cel lulase complex rather than lipids interference with cellulase binding.