Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
Bioresour Technol. 2011 Nov;102(21):9985-90. doi: 10.1016/j.biortech.2011.08.038. Epub 2011 Aug 17.
Mixed sugars from tropical maize stalk juice were used to carry out butanol fermentation with Clostridium beijerinckii NCIMB 8052. Batch experiments employing central composite design (CCD) and response surface methodology (RSM) optimization were performed to evaluate effects of three factors, i.e. pH, initial total sugar concentration, and agitation rate on butanol production. Optimum conditions of pH 6.7, sugar concentration 42.2g/L and agitation rate 48 rpm were predicted, under which a maximum butanol yield of 0.27 g/g-sugar was estimated. Further experiments demonstrated that higher agitation facilitated acetone production, leading to lower butanol selectivity in total acetone-butanol-ethanol (ABE). While glucose and fructose are more preferable by C. beijerinckii, sucrose can also be easily degraded by the microorganism. This study indicated that RSM is a useful approach for optimizing operational conditions for butanol production, and demonstrated that tropical maize, with high yield of biomass and stalk sugars, is a promising biofuel crop.
采用热带玉米秸秆汁中的混合糖，利用拜氏梭菌 NCIMB 8052 进行丁醇发酵。采用中心复合设计（CCD）和响应面法（RSM）优化进行批实验，以评估三个因素（即 pH 值、初始总糖浓度和搅拌速度）对丁醇生产的影响。预测最佳条件为 pH 值 6.7、糖浓度 42.2g/L 和搅拌速度 48 rpm，在此条件下估计最大丁醇产率为 0.27 g/g-糖。进一步的实验表明，较高的搅拌速度有利于丙酮的生产，从而导致总丙酮-丁醇-乙醇（ABE）中的丁醇选择性降低。虽然葡萄糖和果糖更受拜氏梭菌的青睐，但蔗糖也可以被微生物轻易降解。本研究表明，RSM 是优化丁醇生产操作条件的有效方法，并表明生物量和秸秆糖产量高的热带玉米是一种很有前途的生物燃料作物。
