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林产化学与工业 ›› 2015, Vol. 35 ›› Issue (4): 85-91.doi: 10.3969/j.issn.0253-2417.2015.04.014

• 研究报告 • 上一篇    下一篇

稀酸预处理玉米秸秆共发酵产乙醇抑制物的来源探究

蒋发现1,2,3, 黄萍1,3,4, 徐勇1,2,3, 朱均均1,2, 余世袁1,2   

  1. 1. 南京林业大学 化学工程学院, 江苏 南京 210037;
    2. 林木遗传与生物技术教育部重点实验室, 江苏 南京 210037;
    3. 江苏省生物质绿色燃料与化学品重点实验室, 江苏 南京 210037;
    4. 中国林业科学研究院 林产化学工业研究所, 江苏 南京 210042
  • 收稿日期:2014-08-28 出版日期:2015-08-25 发布日期:2015-08-29
  • 通讯作者: 徐勇(1971—),男,湖北安陆人,教授,博士,博士生导师,研究领域为生物化工;E-mail:xuyong@njfu.edu.cn。 E-mail:xuyong@njfu.edu.cn
  • 作者简介:蒋发现(1988—),男,江苏连云港人,硕士生,研究方向为生物化工;E-mail:jfxnjfu@sina.com
  • 基金资助:
    国家自然科学基金资助项目(31370573,31070514);国家863计划资助项目(2012AA022304)

Inhibitors Origination during Dilute Sulfuric Acid Pretreatment of Corn Stover for Ethanol Production by Co-fermentation

JIANG Fa-xian1,2,3, HUANG Ping1,3,4, XU Yong1,2,3, ZHU Jun-jun1,2, YU Shi-yuan1,2   

  1. 1. College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China;
    2. Key Laboratory of Forest Genetics and Biotechnology, Ministry of Education, Nanjing 210037, China;
    3. Jiangsu Key Laboratory of Biomass-based Green Fuels and Chemicals, Nanjing 210037, China;
    4. Institute of Chemical Industry of Forest Products, CAF, Nanjing 210042, China
  • Received:2014-08-28 Online:2015-08-25 Published:2015-08-29

摘要: 针对己糖(葡萄糖)、戊糖(木糖)共发酵产纤维素乙醇抑制物控制的关键性瓶颈,分别以玉米秸秆及玉米秸秆中非木质素的4类组分纤维素、半纤维素、热水提取物和乙醇提取物为原料,并以0.75%稀硫酸和180 ℃预处理40 min得到5种稀酸预处理液。以60 g/L葡萄糖和30 g/L木糖为碳源,分别添加上述稀酸预处理液,比较了5种预处理液对休哈塔假丝酵母(Candida shehatae)共发酵产乙醇的影响,并探究主要抑制物来源。结果表明:133 g/L全玉米秸秆稀酸预处理的降解物会完全抑制C.shehatae糖代谢和共发酵。在玉米秸秆稀酸预处理过程中,4类非木质素组分降解物均会导致乙醇得率下降,其中100 g/L纤维素降解物完全抑制木糖的发酵,半纤维素降解物同时抑制葡萄糖和木糖的发酵,甚至对酵母产生致死毒性,热水提取物和乙醇提取物降解物延滞糖利用和酵母生长。玉米秸秆共发酵产乙醇抑制物主要来自于纤维素和半纤维素在稀酸预处理中的降解反应,主要为甲酸、乙酸、乙酰丙酸、5-羟甲基糠醛和糠醛,同时还存在着其他降解产物的毒性或协同毒性。

关键词: 纤维素乙醇, 发酵抑制物, 非木质素组分, 己糖、戊糖共发酵, 稀硫酸预处理

Abstract: In order to solve the key technical bottleneck for fuel ethanol production regarding the removal of inhibitors during co-fermentation of hexose and pentose, four main non-lignin constituents of corn stover, including cellulose, hemicellulose, hot water extractives and ethanol extractives, were prepared and then treated with 0.75% dilute sulfuric acid at 180 ℃ for 40 min, respectively. 60 g/L glucose and 30 g/L xylose were added to these prehydrolyzates. 5 various ethanolic fermentation medium were fermented to produce ethanol by Candida shehatae, respectively. Thus, the influences on ethanolic co-fermentation and the origination of the key inhibitors were comparatively studied. The results showed that the degradation products formed from 133 g/L corn stover inhibited microbial glycometabolism and co-fermentation totally. During pretreatment of corn stover by dilute sulfuric acid products degraded from four non-lignin constituents reduce the ethanol yield at different extents. Additionally, the products released from the cellulose degradation can completely inhibit the xylose fermentation. Glucose and xylose could be completely inhibited by the degradation products from hemicellulose, and these products perform lethal toxicity to Candida shehatae as well. The products generated from hot water extractives and ethanol extractives exert inhibition on cell growth and sugars utilization. The key inhibitors were mainly from degradation reaction of cellulose and hemicellulose during the pretreatment of corn by stover dilute sulfuric acid. Besides formic acid, acetic acid, levulinic acid, HMF and furfural in corn stover prehydrolyzates, other unknown degradation products also presented toxicity or synergistic inhibition on ethanolic co-fermentation of hexose and pentose.

Key words: cellulosic ethanol, fermentation inhibitors, non-lignin constituents, co-fermentation of hexose and pentose, dilute sulfuric acid pretreatment

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