Effect of furfural on ethanol production by S. cerevisiae in a cross-linked immobilized cell reactor

Abstract

Furfural, a browning reaction product, inhibits yeast ( Saccharomyces cerevisiae) growth and metabolism at low concentration levels in batch culture. The performance of an immobilized cell reactor (ICR) in the presence of 0–2.0 g 1- −t of furfural was examined. Cell growth in the ICR, with and without furfural in the media, indicated that either furfural did not impair glucose utilization, or that the negative effects of furfural were negated by increasing cell density in the reactor. Ethanol yields were constant at 0.48 g ethanol per g glucose regardless of the furfural concentration in the media. Although the specific productivity in the ICR decreased with furfural concentration, the productivity based on liquid hold-up remained constant. Furfural was depleted in the ICR during the experimental operation. Thus, furfural levels of 2.0 g I −1 or less can be tolerated by the yeast for ethanol production in the ICR without negatively affecting reactor performance.