Bioengineering approaches to high-solids cellulose fermentation for biofuel production

用于生物燃料生产的高固体纤维素发酵的生物工程方法

• 批准号: 138130-2011
• 负责人: Levin, David
• 金额: $ 1.82万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2014
• 资助国家: 加拿大
• 起止时间: 2014-01-01 至 2015-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=545486
• 关键词: Bioengineering; approaches; solids; cellulose; fermentation

The long-term objective of the research is to develop a semi-continuous, fed-batch fermentation process using high concentrations (10% or greater) of cellulose as the substrate for biofuels (ethanol and hydrogen) production. Our model organism, Clostridium thermocellum, is a gram-positive, thermophilic, acetogenic, anaerobe that can utilize cellulose as a sole carbon source and synthesizes ethanol, acetate, and other organic acids via a mixed fermentation metabolism, with the concomitant release of hydrogen (H2) and carbon dioxide (CO2). This research will focus on development of the high solids fermentation process. Biofuel production from cellulose fermentation presents a number of unique biological and engineering challenges, such as: i) how to move insoluble substrate at high concentration into, and mix the substrate within, a bioreactor; ii) how to quantify conversion of the substrate from long polymers of glucose to oligocellulodextrins and/or soluble sugars (cellobiose and glucose); iii) how to quantify cell growth on an insoluble substrate; iv) how to recover the ethanol produced from the vapour phase of the fermentation reaction; and v) how to purify, capture, and store the hydrogen produced. The goal of this proposed NSERC Discovery grant is to build upon the progress that we have made and address these challenges. The short-term objectives of this proposal are to: 1) develop a reliable and accurate method to quantify rates of substrate conversion during cellulose fermentation; 2) quantify cell growth on an insoluble substrate; and 3) integrate and validate a continuous, real-time monitoring system for metabolites during cellulose fermentation. This research bridges the gap between science and engineering to develop a Consolidated Bioprocessing approach for biofuel production using cellulose as a substrate for fermentation. Consolidated Bioprocessing of cellulosic substrates offers significant potential as a viable process for next generation biofuel production by reducing upstream processing costs.

该研究的长期目标是开发一种半连续的分批补料发酵工艺，使用高浓度（10%或更高）的纤维素作为生物燃料（乙醇和氢气）生产的底物。我们的模式生物，热纤梭菌，是一种革兰氏阳性，嗜热，产乙酸，厌氧菌，可以利用纤维素作为唯一的碳源，并合成乙醇，乙酸，和其他有机酸通过混合发酵代谢，伴随着氢气（H2）和二氧化碳（CO2）的释放。本研究将致力于高固体发酵工艺的开发。从纤维素发酵生产生物燃料提出了许多独特的生物和工程挑战，例如：i）如何将高浓度的不溶性底物移动到生物反应器中并在生物反应器内混合底物; ii）如何量化底物从葡萄糖的长链聚合物到寡聚纤维素糊精和/或可溶性糖的转化。在一些实施方案中，所述方法包括：i）如何定量细胞生长（纤维二糖和葡萄糖）; iii）如何定量在不溶性底物上的细胞生长; iv）如何回收从发酵反应的气相产生的乙醇;以及v）如何纯化、捕获和储存产生的氢。这个提议的NSERC发现补助金的目标是建立在我们已经取得的进展和解决这些挑战的基础上。该提案的短期目标是：1）开发一种可靠且准确的方法来量化纤维素发酵期间的底物转化率; 2）量化不溶性底物上的细胞生长;和3）整合并验证连续、实时的监测系统纤维素发酵期间的代谢物。这项研究弥合了科学和工程之间的差距，以开发一种使用纤维素作为发酵底物的生物燃料生产的综合生物加工方法。纤维素基质的综合生物加工通过降低上游加工成本，作为下一代生物燃料生产的可行工艺具有巨大潜力。