Extraction and hydrolysis of levoglucosan from pyrolysis oil.
Fermentable sugar obtained from lignocellulosic material exhibits great potential as a renewable feedstock for the production of bio-ethanol. One potentially viable source of fermentable sugars is pyrolysis oil, commonly called bio-oil. Depending on the type of lignocellulosic material and the operating conditions used for pyrolysis, bio-oil can contain upwards of 10 wt% of 1,6-anhydro-beta-D-glucopyranose (levoglucosan, LG), an anhydrosugar that can be hydrolyzed to glucose. This research investigated the extraction of levoglucosan from pyrolysis oil via phase separation, the acid-hydrolysis of the levoglucosan into glucose, and the subsequent fermentation of this hydrolysate into ethanol. Optimal selection of water-to-oil ratio, temperature and contact time yielded an aqueous phase containing a levoglucosan concentration of up to 87 g/L, a yield of 7.8 wt% of the bio-oil. Hydrolysis conditions of 125 degrees C, 44 min and 0.5 M H(2)SO(4) resulted in a maximum glucose yield of 216% (when based on original levoglucosan), inferring other precursors of glucose were present in the aqueous phase. The aqueous phase contained solutes which inhibited fermentation, however, up to 20% hydrolysate solutions were efficiently fermented (yield=0.46 g EtOH/g glucose; productivity=0.55 g/L h) using high yeast inoculums (1 g/L in flask) and micro-aerophilic conditions.
Bennett
Nicole M
NM
UBC, Department of Chemical and Biological Engineering, 2360 East Mall, Vancouver, BC, Canada V6T 1Z3.
Helle
Steve S
SS
Duff
Sheldon J B
SJ
D000143:Acids / Q000737:chemistry; D018533:Biomass; D001709:Biotechnology / Q000379:methods; D002241:Carbohydrates / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D005285:Fermentation; D005947:Glucose / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification; D006868:Hydrolysis; D008031:Lignin / Q000737:chemistry; D009821:Oils; D013696:Temperature; D014867:Water / Q000737:chemistry
D000143:Acids; D002241:Carbohydrates; D009821:Oils; D014867:Water; C036909:lignocellulose; D000431:Ethanol; C014989:1,6-anhydro-beta-glucopyranose; D008031:Lignin; D005947:Glucose