Xu Lei, Tschirner Ulrike
Biosystems and Bioproducts Engineering, University of Minnesota, Saint Paul, MN, 55108, USA,
Bioprocess Biosyst Eng. 2014 Aug;37(8):1551-9. doi: 10.1007/s00449-014-1127-3. Epub 2014 Feb 4.
Clostridium thermocellum/Clostridium thermolacticum co-culture fermentation has been shown to be a promising way of producing ethanol from several carbohydrates. In this research, immobilization techniques using sodium alginate and alkali pretreatment were successfully applied on this co-culture to improve the bio-ethanol fermentation performance during consolidated bio-processing (CBP). The ethanol yield obtained increased by over 60 % (as a percentage of the theoretical maximum) as compared to free cell fermentation. For cellobiose under optimized conditions, the ethanol yields were approaching about 85 % of the theoretical efficiency. To examine the feasibility of this immobilization co-culture on lignocellulosic biomass conversion, untreated and pretreated aspen biomasses were also used for fermentation experiments. The immobilized co-culture shows clear benefits in bio-ethanol production in the CBP process using pretreated aspen. With a 3-h, 9 % NaOH pretreatment, the aspen powder fermentation yields approached 78 % of the maximum theoretical efficiency, which is almost twice the yield of the untreated aspen fermentation.
热纤梭菌/热乳酸梭菌共培养发酵已被证明是从多种碳水化合物生产乙醇的一种有前景的方法。在本研究中，使用海藻酸钠的固定化技术和碱预处理成功应用于这种共培养，以提高在同步糖化发酵（CBP）过程中的生物乙醇发酵性能。与游离细胞发酵相比，获得的乙醇产量提高了60%以上（占理论最大值的百分比）。在优化条件下，对于纤维二糖，乙醇产量接近理论效率的85%左右。为了检验这种固定化共培养对木质纤维素生物质转化的可行性，未处理和预处理的白杨生物质也用于发酵实验。在使用预处理白杨的CBP过程中，固定化共培养在生物乙醇生产中显示出明显优势。经过3小时、9%氢氧化钠预处理后，白杨粉末发酵产量接近最大理论效率的78%，几乎是未处理白杨发酵产量的两倍。
