Białas Wojciech, Czerniak Adrian, Szymanowska-Powałowska Daria
Department of Biotechnology and Food Microbiology, Poznan University of Life Sciences, Poznań, Poland.
Acta Biochim Pol. 2014;61(1):153-62. Epub 2014 Mar 20.
Fuel ethanol production, using a simultaneous saccharification and fermentation process (SSF) of native starch from corn flour, has been performed using Saccharomyces cerevisiae and a granular starch hydrolyzing enzyme. The quantitative effects of mash concentration, enzyme dose and pH were investigated with the use of a Box-Wilson central composite design protocol. Proceeding from results obtained in optimal fermentation conditions, a kinetics model relating the utilization rates of starch and glucose as well as the production rates of ethanol and biomass was tested. Moreover, scanning electron microscopy (SEM) was applied to investigate corn starch granule surface after the SFF process. A maximum ethanol concentration of 110.36 g/l was obtained for native corn starch using a mash concentration of 25%, which resulted in ethanol yield of 85.71%. The optimal conditions for the above yield were found with an enzyme dose of 2.05 ml/kg and pH of 5.0. These results indicate that by using a central composite design, it is possible to determine optimal values of the fermentation parameters for maximum ethanol production. The investigated kinetics model can be used to describe SSF process conducted with granular starch hydrolyzing enzymes. The SEM micrographs reveal randomly distributed holes on the surface of granules.
利用酿酒酵母和颗粒淀粉水解酶，采用玉米粉中天然淀粉的同步糖化发酵工艺（SSF）生产燃料乙醇。使用Box-Wilson中心复合设计方案研究了醪液浓度、酶用量和pH值的定量影响。根据在最佳发酵条件下获得的结果，测试了一个将淀粉和葡萄糖利用率以及乙醇和生物质生产率相关联的动力学模型。此外，应用扫描电子显微镜（SEM）研究同步糖化发酵过程后玉米淀粉颗粒的表面。使用25%的醪液浓度，天然玉米淀粉获得了最高乙醇浓度110.36 g/l，乙醇产率为85.71%。上述产率的最佳条件是酶用量为2.05 ml/kg，pH值为5.0。这些结果表明，通过使用中心复合设计，可以确定用于最大乙醇产量的发酵参数的最佳值。所研究的动力学模型可用于描述用颗粒淀粉水解酶进行的同步糖化发酵过程。扫描电子显微镜照片显示颗粒表面有随机分布的孔洞。
