초록
Bioethanol production in batch culture by free Saccharomyces cerevisiae cells from intermediates of sugar beet processing was investigated and compared with molasses, traditionally used substrate. The overall fermentation efficiency of different yeasts was examined and there is no statistical difference between them indicating that the criteria for yeast strain choice should be based on availability and cost-effective factor. When raw, thin and thick juices and molasses were used, under anaerobic conditions for 60h, at the temperature of 30<SUP>o</SUP>C and agitation rate 3.3Hz, obtained ethanol contents were 82.87dm<SUP>3</SUP>m<SUP>-3</SUP>, 80.31dm<SUP>3</SUP>m<SUP>-3</SUP>, 80.70dm<SUP>3</SUP>m<SUP>-3</SUP> and 73.96dm<SUP>3</SUP>m<SUP>-3</SUP>, respectively. The ethanol yield amounted 490gkg<SUP>-1</SUP> for media based on intermediates and 450gkg<SUP>-1</SUP> for mash prepared with molasses. Response surface methodology was used for description of ethanol production. By obtained mathematical model (second degree polynomial), optimal fermentation duration is estimated on 36h for intermediates, while for molasses it reaches 50h. Bioethanol production from intermediates of sugar beet processing is technically possible and enables higher effectiveness of process.