In several of our previous publications we have demonstrated high sugar conversion and high ethanol yield using Ammonia Fiber Expansion (AFEX) treated biomass in separate hydrolysis and fermentation (SHF). In those experiments commercial enzymes were used to do enzymatic hydrolysis and engineered ethanologenic strains were applied to ferment glucose and xylose simultaneously. Until now, no investigation has been reported about Consolidated Bioprocessing (CBP) on AFEX treated biomass, which performs enzymes production, enzymatic hydrolysis and fermentation in one bioreactor. It is strongly believed that CBP is the most economic way to produce biofuel in a biorefinery.
In this study, Clostridium Phytofermentans (ATCC 700394) was used as a CBP microbe to produce ethanol from AFEX treated corn stover (AFEX-CS). Without washing, detoxification, and nutrient supplementation, the microbe grew and fermented very well on AFEX-CS. For the sake of comparison we also performed CBP experiments using pure cellulose, untreated CS, and washed AFEX-CS. The effects of AFEX-CS wash stream (with degradation products) on ethanol and metabolites from fermentation on CBP performance were also investigated.