Fungal β-glucosidase expression in Saccharomyces cerevisiae.
Recombinant Saccharomyces cerevisiae strains expressing β-glucosidases from Thermoascus aurantiacus (Tabgl1) and Phanerochaete chrysosporium (PcbglB and Pccbgl1) were constructed and compared to S. cerevisiae Y294[SFI], previously identified as the best β-glucosidase-producing strain. The PcbglB was also intracellularly expressed in combination with the lac12 lactose permease of Kluyveromyces lactis in S. cerevisiae Y294[PcbglB + Lac12]. The recombinant extracellular β-glucosidases indicated maximum activity in the pH range 4-5 and temperature optima varying from 50 to 75 °C. The S. cerevisiae Y294[Pccbgl1] strain performed best under aerobic and anaerobic conditions, producing 2.6 times more β-glucosidase activity than S. cerevisiae Y294[SFI] and an ethanol concentration of 4.8 g l(-1) after 24 h of cultivation on cellobiose as sole carbohydrate source. S. cerevisiae Y294[Tabgl1] was unable to grow on cellobiose (liquid medium), whereas S. cerevisiae Y294[PcbglB + Lac12] exhibited limited growth.
Department of Microbiology, University of Stellenbosch, Stellenbosch 7600, South Africa.
A P
AP
Njokweni
S H
SH
Rose
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WH
van Zyl
D000693:Anaerobiosis; D002475:Cellobiose / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D000431:Ethanol / Q000378:metabolism / Q000600:supply & distribution; D005285:Fermentation; D007716:Kluyveromyces / Q000201:enzymology / Q000235:genetics; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D020075:Phanerochaete / Q000201:enzymology / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D055327:Thermoascus / Q000201:enzymology / Q000235:genetics; D001617:beta-Glucosidase / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism
D026901:Membrane Transport Proteins; D011994:Recombinant Proteins; D002475:Cellobiose; D000431:Ethanol; D002482:Cellulose; C021499:lactose permease; D001617:beta-Glucosidase