Biosynthesis regulation of the beta-glucosidase produced by a yeast strain transformed by genetic engineering.
The biosynthesis of the beta-glucosidase enzyme was studied in a transformed yeast obtained by cloning in Saccharomyces cerevisiae the structural gene coding for beta-glucosidase in Kluyveromyces fragilis. The enzyme biosynthesis was found to be non-adaptative, and repressed by glucose. These features are similar to those observed in K. fragilis. beta-Glucosidase activity in the transformed yeast was much higher than in K. fragilis. We attempted to ferment cellobiose with the transformed yeast: practically no cellobiose was consumed, growth and ethanol production were negligible. Warburg experiments showed that cellobiose fermentation did not occur when the respiratory chain was not functioning.
D002475:Cellobiose / Q000378:metabolism; D003001:Cloning, Molecular; D005285:Fermentation; D005800:Genes, Fungal; D005947:Glucose / Q000378:metabolism; D005959:Glucosidases / Q000096:biosynthesis*; D007716:Kluyveromyces / Q000201:enzymology* / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D004718:Saccharomycetales / Q000201:enzymology*; D001617:beta-Glucosidase / Q000096:biosynthesis*
D002475:Cellobiose; D005959:Glucosidases; D001617:beta-Glucosidase; D005947:Glucose