Biological and Ecological Engineering, Oregon State University, 122 Gilmore Hall, Corvallis, OR 97331, USA.
Bioprocess Biosyst Eng. 2011 Sep;34(7):879-90. doi: 10.1007/s00449-011-0539-6. Epub 2011 Apr 13.
Efficiency of the starch hydrolysis in the dry grind corn process is a determining factor for overall conversion of starch to ethanol. A model, based on a molecular approach, was developed to simulate structure and hydrolysis of starch. Starch structure was modeled based on a cluster model of amylopectin. Enzymatic hydrolysis of amylose and amylopectin was modeled using a Monte Carlo simulation method. The model included the effects of process variables such as temperature, pH, enzyme activity and enzyme dose. Pure starches from wet milled waxy and high-amylose corn hybrids and ground yellow dent corn were hydrolyzed to validate the model. Standard deviations in the model predictions for glucose concentration and DE values after saccharification were less than ± 0.15% (w/v) and ± 0.35%, respectively. Correlation coefficients for model predictions and experimental values were 0.60 and 0.91 for liquefaction and 0.84 and 0.71 for saccharification of amylose and amylopectin, respectively. Model predictions for glucose (R2 = 0.69-0.79) and DP4+ (R2 = 0.8-0.68) were more accurate than the maltotriose and maltose for hydrolysis of high-amylose and waxy corn starch. For yellow dent corn, simulation predictions for glucose were accurate (R2 > 0.73) indicating that the model can be used to predict the glucose concentrations during starch hydrolysis.
干法玉米加工中淀粉水解的效率是淀粉到乙醇整体转化率的决定因素。本文开发了一种基于分子方法的模型，用于模拟淀粉的结构和水解。淀粉结构基于支链淀粉的簇模型进行建模。使用蒙特卡罗模拟方法对直链淀粉和支链淀粉的酶解进行建模。该模型包括温度、pH 值、酶活性和酶剂量等工艺变量的影响。对来自湿法磨制糯玉米和高直链淀粉玉米杂交种以及黄玉米的纯淀粉进行水解，以验证模型。糖化后葡萄糖浓度和 DE 值的模型预测标准偏差小于±0.15%（w/v）和±0.35%，分别。液化和直链淀粉和支链淀粉糖化的模型预测值与实验值的相关系数分别为 0.60 和 0.91，0.84 和 0.71。对于高直链淀粉玉米和糯玉米淀粉的水解，葡萄糖（R2=0.69-0.79）和 DP4+（R2=0.8-0.68）的模型预测比麦芽三糖和麦芽糖更准确。对于黄玉米，葡萄糖的模拟预测准确（R2>0.73），表明该模型可用于预测淀粉水解过程中的葡萄糖浓度。
