Dynamics of Ethanol Production from Deproteinized Whey by Kluyveromyces marxianus: An Analysis About Buffering Capacity, Thermal and Nitrogen Tolerance

The production of value-added products could be a valuable option for cheese wastewater management. However, this kind of study cannot just focus alone on getting the final product. This also necessitates studies on the dynamics of bioprocesses. With these as background, the present investigation aimed at evaluating the buffering capacity of deproteinized whey and effect of temperature and nitrogen source on ethanol yields from it. The batch fermentation conditions used to evaluate ethanol production were temperatures 30, 35, 40 degrees C and pH 4.5, 5.0, 5.5, 6.0. To study the influence of nitrogen source on ethanol yield, a design matrix was applied using yeast extract and (NH4)(2)SO4. The final pH was analyzed to evaluate the buffering capacity. The results showed that the Kluyveromyces marxianus was thermotolerance to produce ethanol at 35 and 40 degrees C, which was not observed at 30 degrees C. Results also showed that the deproteinization procedure did not affect the buffering capacity of cheese whey. Finally, higher ethanol production was obtained using yeast extract (3% v/v). These results could be important for developing low-cost method for industrial production of ethanol from deproteinized whey.