Bennett Nicole M, Helle Steve S, Duff Sheldon J B
UBC, Department of Chemical and Biological Engineering, 2360 East Mall, Vancouver, BC, Canada V6T 1Z3.
Bioresour Technol. 2009 Dec;100(23):6059-63. doi: 10.1016/j.biortech.2009.06.067. Epub 2009 Jul 18.
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.
从木质纤维素材料中获得的可发酵糖作为生产生物乙醇的可再生原料具有巨大潜力。一种潜在可行的可发酵糖来源是热解油，通常称为生物油。根据木质纤维素材料的类型和用于热解的操作条件，生物油可含有超过10 wt%的1,6-脱水-β-D-吡喃葡萄糖（左旋葡聚糖，LG），一种可水解为葡萄糖的脱水糖。本研究调查了通过相分离从热解油中提取左旋葡聚糖、将左旋葡聚糖酸水解为葡萄糖以及随后将该水解产物发酵为乙醇的过程。水油比、温度和接触时间的最佳选择产生了一个水相，其中左旋葡聚糖浓度高达87 g/L，占生物油的产率为7.8 wt%。125℃、44分钟和0.5 M H₂SO₄的水解条件导致最大葡萄糖产率为216%（基于原始左旋葡聚糖），这表明水相中存在葡萄糖的其他前体。然而，水相中含有抑制发酵的溶质，使用高酵母接种量（烧瓶中为1 g/L）和微需氧条件，高达20%的水解产物溶液能有效发酵（产率 = 0.46 g乙醇/g葡萄糖；生产率 = 0.55 g/L·h）。
