Simultaneous detoxification, saccharification, and ethanol fermentation of weak-acid hydrolyzates

Abstract

Lignocellulosic feedstocks can be prepared for ethanol fermentation by pre-treatment with a dilute mineral acid catalyst that hydrolyzes the hemicellulose and opens up the plant cell wall fibers for subsequent enzymatic saccharification. The acid catalyzed reaction scheme is sequential whereby released monosaccharides are further degraded to furans and other chemicals that are inhibitory to the next fermentation step. This work evaluated the use of agricultural residue (flax shive) as starting material for making activated biochar to adsorb these degradation products. Results show that both furfural and hydroxymethylfurfural (HMF) are adsorbed by steam-activated biochar prepared from flax shive. Decontamination of the hydrolyzate significantly improved the fermentation behavior by Saccharomyces cerevisiae yeast, including significantly reducing the lag phase of the fermentation, when the amount of biochar added to the fermentation broth was 2.5% (w/v). No negative effects were noted from addition of activated char to the process.