Continuous ethanol fermentation of lactose by a recombinant flocculating Saccharomyces cerevisiae strain.
Alcohol fermentation of lactose was investigated using a recombinant flocculating Saccharomyces cerevisiae, expressing the LAC4 (coding for beta-galactosidase) and LAC12 (coding for lactose permease) genes of Kluyveromyces marxianus. Data on yeast fermentation and growth on a medium containing lactose as the sole carbon source are presented. In the range of studied lactose concentrations, total lactose consumption was observed with a conversion yield of ethanol close to the expected theoretical value. For the continuously operating bioreactor, an ethanol productivity of 11 g L(-1) h(-1) (corresponding to a feed lactose concentration of 50 g L(-1) and a dilution rate of 0.55 h(-1)) was obtained, which is 7 times larger than the continuous conventional systems. The system stability was confirmed by keeping it in operation for 6 months.
Centro de Engenharia Biológica-IBQF, Universidade do Minho, Braga, Portugal.
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Domingues
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Dantas
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Lima
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Teixeira
D019149:Bioreactors; D000431:Ethanol / Q000138:chemical synthesis / Q000378:metabolism*; D005285:Fermentation; D005427:Flocculation; D007785:Lactose / Q000378:metabolism*; D011994:Recombinant Proteins; D012441:Saccharomyces cerevisiae / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D013045:Species Specificity
D011994:Recombinant Proteins; D000431:Ethanol; D007785:Lactose