Conversion of furfural in aerobic and anaerobic batch fermentation of glucose by Saccharomyces cerevisiae

The effect of furfural on aerobic and anaerobic batch cultures of Saccharom yces cerevisiae CBS 8066 growing on glucose was investigated. Furfural was found to decrease both the specific growth rate and ethanol production rate after pulse additions in both anaerobic and aerobic batch cultures. The sp ecific growth rate remained low until the furfural had been completely cons umed, and then increased somewhat, but not to the initial value. The CO2 ev olution rate decreased to about 35% of the value before the addition of 4 g l(-1) furfural, in both aerobic and anaerobic fermentations. The decrease of the CO2 evolution rate was rapid at first, and then a more gradual decre ase was observed. The furfural was converted mainly to furfuryl alcohol, wi th a specific conversion rate of 0.6 (+/- 0.03) g (furfural) g(-1) (biomass ) h(-1) by exponentially growing cells. However, the conversion rate of fur fural by cells in the stationary phase was much lower. A previously unident ified compound was detected during the conversion of furfural. This compoun d was characterized by mass spectrometry and it is suggested that it is for med from furfural and pyruvate.