Ethanol from Sugar Cane: Flask Experiments Using the EX-FERM Technique

Abstract

Alcohol production at the laboratory scale from sugar cane pieces by the EX-FERM technique was studied with 37 strains of Saccharomyces spp. The EX-FERM process is novel in that it employs the simultaneous extraction and fermentation of the sucrose in a cane-water suspension. Two types of cane treatments were used: chips and shredded pith, either fresh or dried. A mother culture of the yeast was prepared in enriched cane juice and then added to the cane-water mixture. After static fermentation for 40 h at 30°C, the cane was removed, and fresh cane was added to the yeast-alcohol broth. After an additional 24 h, the cane was again removed and the liquor was analyzed. After the first 40-h cycle, sugar consumption was above 99% with 10 of the 37 yeast strains tested, and ethanol reached levels of 1.29 to 4.00 g per 100 ml, depending on the yeast strain. The final ethanol concentration reached 4.27 to 5.37 g per 100 ml, and sugar consumption was above 98% in three cases during a second EX-FERM cycle employing previously air-dried chips and pith. Product yields were within accepted values. Cane treatment did not appear to affect the results at this level.