Lactose/whey utilization and ethanol production by transformed Saccharomyces cerevisiae cells

✍ Scribed by Danilo Porro; Enzo Martegani; Bianca Maria Ranzi; Lilia Alberghina

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 629 KB
• Volume: 39
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/bit.260390802

✦ Synopsis

Strains of Saccharornyces cerevisiae transformed with a multicopy expression vector bearing both the Escherichia coli P-galactosidase gene under the control of the upstream activating sequence of the GALI-10 genes and the GAL4 activator gene release part of P-galactosidase in the growth medium. This release is due to cell lysis of the older mother cells; the enzyme maintains its activity in buffered growth media. Fermentation studies with transformed yeast strains showed that the release of @-galactosidase allowed an ef- ficient growth on buffered media containing lactose as carbon source as well as on whey-based media. The transformed strains utilized up to 95% of the lactose and a high growth yield was obtained in rich media. High productions of ethanol were also observed in stationary phase after growth in lactose minimal media.