Mosier Nathan, Hendrickson Richard, Ho Nancy, Sedlak Miroslav, Ladisch Michael R
Laboratory of Renewable Resources Engineering, Purdue University, 1290 Porter Building, LORRE, 500 Central Drive, West Lafayette, IN 47907-2022, United States.
Bioresour Technol. 2005 Dec;96(18):1986-93. doi: 10.1016/j.biortech.2005.01.013.
Controlled pH, liquid hot water pretreatment of corn stover has been optimized for enzyme digestibility with respect to processing temperature and time. This processing technology does not require the addition of chemicals such as sulfuric acid, lime, or ammonia that add cost to the process because these chemicals must be neutralized or recovered in addition to the significant expense of the chemicals themselves. Second, an optimized controlled pH, liquid hot water pretreatment process maximizes the solubilization of the hemicellulose fraction as liquid soluble oligosaccharides while minimizing the formation of monomeric sugars. The optimized conditions for controlled pH, liquid hot water pretreatment of a 16% slurry of corn stover in water was found to be 190 degrees C for 15 min. At the optimal conditions, 90% of the cellulose was hydrolyzed to glucose by 15FPU of cellulase per gram of glucan. When the resulting pretreated slurry, in undiluted form, was hydrolyzed by 11FPU of cellulase per gram of glucan, a hydrolyzate containing 32.5 g/L glucose and 18 g/L xylose was formed. Both the xylose and the glucose in this undiluted hydrolyzate were shown to be fermented by recombinant yeast 424A(LNH-ST) to ethanol at 88% of theoretical yield.
针对加工温度和时间，对玉米秸秆进行了可控pH值的液态热水预处理，以优化酶消化率。这种加工技术不需要添加硫酸、石灰或氨等化学物质，这些化学物质会增加加工成本，因为除了化学物质本身的高昂成本外，还必须对其进行中和或回收。其次，优化的可控pH值液态热水预处理工艺可使半纤维素部分以液态可溶性低聚糖的形式最大程度地溶解，同时使单糖的形成最小化。发现对16%的玉米秸秆水浆进行可控pH值液态热水预处理的优化条件为190℃处理15分钟。在最佳条件下，每克葡聚糖用15FPU的纤维素酶可将90%的纤维素水解为葡萄糖。当所得未经稀释的预处理浆料每克葡聚糖用11FPU的纤维素酶进行水解时，会形成含有32.5 g/L葡萄糖和18 g/L木糖的水解产物。该未经稀释的水解产物中的木糖和葡萄糖均被重组酵母424A(LNH-ST)发酵为乙醇，产率为理论产率的88%。
