Continuous ethanol production from concentrated wood hydrolysates in an internal membrane-filtration bioreactor

Continuous culture for the production of ethanol from wood hydrolysate was carried out in an internal membrane-filtration bioreactor. The hydrolysate medium was sterilized at a relatively low temperature of 60 degrees C with the intention of reducing the formation of inhibitory compounds during the sterilization, The maximum ethanol concentration and productivity obtained in this study were 76.9 g/L and 16.9 g/L-h, respectively, which were much h igher than those (57.2-67 g/L and 0.3-1-0 g/L-h) obtained in batch cultures using hydrolysate media sterilized at 60 degrees C. The productivity was a lso found to be much higher than that (6.7 g/L-h) obtained in a continuous cell retention culture using a wood hydrolysate sterilized at 121 degrees C . These results show that the internal membrane-filtration bioreactor in co mbination with low-temperature sterilization could be very effective for et hanol production from wood hydrolysate.