PRODUCTION OF ETHANOL FROM MOLASSES AT 45 DEGREES-C USING ALGINATE-IMMOBILIZED KLUYVEROMYCES-MARXIANUS IMB3

The thermotolerant, ethanol-producing yeast strain, Kluyveromyces marx ianus IMB3, has been immobilized in calcium alginate matrices. The abi lity of the biocatalyst to produce ethanol from cane molasses originat ing in Guatemala, Honduras, Senegal, Guyana and the Philippines was ex amined. In each case the molasses was diluted to yield a sugar concent ration of 140 g/l and fermentations were carried out in batch-fed mode at 45 degrees C. During the first 24 hours, the maximum ethanol conce ntrations obtained ranged from 43-57 g/l with optimum production on th e molasses from Honduras. Ethanol production during subsequent re-feed ing of the fermentations at 24-hour intervals over a 120-hour period, decreased steadily to concentrations ranging from 20-36 gn and it was found that ethanol productivity remained highest in fermentations cont aining the molasses from Guyana. When each set of fermentations was re -fed at 120 h and allowed to continue for 48 h, ethanol production aga in increased to a maximum with concentrations ranging from 25-52 g/l. It was also found however, that increasing the time between re-feeding at this stage in fermentation had a detrimental effect on the functio nality of the biocatalyst.