STUDY OF A SINGLE AND MIXED CULTURE FOR THE DIRECT BIO-CONVERSION OF SORGHUM CARBOHYDRATES TO ETHANOL

Fusarium oxysporum F3 alone or in mixed culture with Saccharomyces cer evisiae 2541 fermented soluble and insoluble carbohydrates of sweet so rghum stalk directly to ethanol. Both microorganisms were first grown aerobically and fermented sorghum stalk to ethanol thereafter. During fermentation, insoluble carbohydrates were hydrolysed to soluble sugar s by the celluloytic system of F. oxysporum. Ethanol yields as high as 24.4 and 33.5 g/100 g dry stalks were obtained by F. oxysporum and th e mixed culture respectively, representing a theoretical yield enhance ment of 11.6% and 53.6% respectively. The corresponding ethanol concen trations in the fermentation medium were 4.6% and 6.4% (w/v). These re sults clearly demonstrated that a large portion of insoluble carbohydr ate from sorbghum was converted by simultaneous saccharification and f ermentation to ethanol, making the process promising for bioethanol pr oduction.