Ethanolic fermentation of bio-oil hydrolysate
Livingston, Darrell Rex
As production of ethanol climbs, non-food feedstocks need to be utilized such as lignocellulosic biomass. The sugars present in bio-oil produced by fast pyrolysis can potentially be fermented by microbial organisms to produce cellulosic ethanol. This study shows the potential for microbial digestion of the aqueous fraction of bio-oil in an enrichment medium to consume glucose and produce ethanol. In addition to glucose, inhibitors such as furans and phenols are present in the bio-oil. A pure glucose enrichment medium of 20 g/L was used as a standard to compare with glucose and aqueous fraction mixtures for digestion. 30% by volume of aqueous fraction in media was the most that could be consumed and yielded 0.4 g of ethanol per g of glucose. Inhibitor removal tests by extraction, activated carbon, air stripping, and microbial means were also mildly successful. Ethanol could potentially be produced for $14 per gallon using these methods.