Production of bioethanol from organic whey using Kluyveromyces marxianus.
Ethanol production by K. marxianus in whey from organic cheese production was examined in batch and continuous mode. The results showed that no pasteurization or freezing of the whey was necessary and that K. marxianus was able to compete with the lactic acid bacteria added during cheese production. The results also showed that, even though some lactic acid fermentation had taken place prior to ethanol fermentation, K. marxianus was able to take over and produce ethanol from the remaining lactose, since a significant amount of lactic acid was not produced (1-2 g/l). Batch fermentations showed high ethanol yield (~0.50 g ethanol/g lactose) at both 30°C and 40°C using low pH (4.5) or no pH control. Continuous fermentation of nonsterilized whey was performed using Ca-alginate-immobilized K. marxianus. High ethanol productivity (2.5-4.5 g/l/h) was achieved at dilution rate of 0.2/h, and it was concluded that K. marxianus is very suitable for industrial ethanol production from whey.
Christensen
Anne Deen
AD
Biosystems Division, Bioprocessing Programme, National Laboratory for Sustainable Energy, Technical University of Denmark (Risø DTU), Frederiksborgvej 399, Roskilde, Denmark.
Kádár
Zsófia
Z
Oleskowicz-Popiel
Piotr
P
Thomsen
Mette Hedegaard
MH
D056804:Biofuels; D001709:Biotechnology / Q000379:methods*; D002611:Cheese; D000431:Ethanol / Q000032:analysis / Q000378:metabolism*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D007716:Kluyveromyces / Q000378:metabolism*; D007785:Lactose / Q000378:metabolism; D013696:Temperature
D056804:Biofuels; D000431:Ethanol; D007785:Lactose