title: Methods for mitigation of bio-oil extract toxicity.
abstract: Levoglucosan (1,6-anhydro-beta-d-glucopyranose) and other anhydrosugars can be produced in significant quantities during fast pyrolysis of lignocellulosic material. Levoglucosan can be extracted and hydrolyzed to produce fermentable glucose, however co-extraction of fermentation inhibitors can reduce ethanol yields. This work was aimed at evaluating various methods for mitigating the toxicity of bio-oil aqueous extract. Among the detoxification techniques tested, it was found that overliming and solvent extraction were able to improve the fermentability of bio-oil hydrolyzates. Overliming was able to increase the yield of ethanol from bio-oil hydrolyzate by 0.19+/-0.01 (g ethanol/g glucose) at 50% volume hydrolyzate and 0.45+/-0.05 (g ethanol/g glucose) at 40% volume hydrolyzate. A number of extractants were examined and the best solvent was tri-n-octylamine with co-solvent 1-octanol. It was able to selectively (100% glucose retention) remove at least 90+/-6.8% of acetic acid, which was the targeted inhibitor in bio-oil hydrolyzate. This increased the ethanol yield by 0.24 (g ethanol/g glucose) at 40% volume of hydrolyzate. In addition, a technique called adaptive evolution of yeasts was applied, which was capable of increasing the ethanol yield by up to 39% when compared with the unadapted parental strains.
authors.affiliation: The University of British Columbia, Department of Chemical and Biological Engineering, 2360 East Mall, Vancouver, BC, Canada V6T 1Z3.
authors.forename: Jacky K S
authors.initials: JK
authors.lastname: Chan
authors.forename: Sheldon J B
authors.initials: SJ
authors.lastname: Duff
mesh_terms: D056804:Biofuels / Q000633:toxicity*; D005285:Fermentation; D005947:Glucose / Q000031:analogs & derivatives* / Q000633:toxicity; D006868:Hydrolysis; D015003:Yeasts / Q000378:metabolism
chemical_list: D056804:Biofuels; C014989:1,6-anhydro-beta-glucopyranose; D005947:Glucose