Impact of sodium or potassium cations in culture medium to ethanol fermentation by saccharomyces cerevisiae

Abstract

In bioethanol from acid hydrolysis process, neutralization of acid hydrolyzate is essential step, which resulted in dissolved cations in glucose solution. Impact of cations to Saccharomyces cerevisiae in glucose solution was investigated focused on ethanol fermentation. Both potassium and sodium cations decreased the ethanol fermentation and glucose to ethanol conversion as potassium or sodium cations. In sodium cation, more than 1.13 N sodium cation in glucose solution led to ethanol production less than theoretical yield with severe inhibition. In 1.13 N sodium cation concentration, ethanol fermentation was slowed down to reach the maximum ethanol concentration with 48 h fermentation compared with 24 h fermentation in control (no sodium cation in glucose solution). In case of potassium cation, three different levels of potassium led to silimar ethanol concentration even though slight slow down of ethanol fermentation with increasing potassium cation concentration at 12 h fermentation. Sodium cation showed more inhibition than potassium cation as ethanol concentration and glucose consumption by Saccharomyces cerevisiae.