Development of a process model for simultaneous saccharification and fermentation (SSF) of algal starch to third-generation bioethanol
Development of a process model for simultaneous saccharification and fermentation (SSF) of algal starch to third-generation bioethanol
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DOI：
10.1080/17597269.2018.1426162
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发表时间：
2018-02
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影响因子：
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通讯作者：
S. Singh;I. Chakravarty;K. D. Pandey;S. Kundu
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文献类型：
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作者：
S. Singh;I. Chakravarty;K. D. Pandey;S. Kundu
摘要利用微藻淀粉生产乙醇是一种很有前途的替代燃料，同时糖化发酵（SSF）是将淀粉的酶解转化为葡萄糖和酿酒酵母的葡萄糖发酵转化为乙醇在一个步骤中结合起来。淀粉含量在一种微生物小球藻中增加，通过放线菌酮处理从19.3%至38.2%（w/w）。使用由尼日尔曲霉产生的活性为40 U mL-1的粗淀粉酶来水解微藻淀粉。研究了SSF工艺在生物乙醇生产中的应用。酿酒酵母，并且产生0.116g乙醇/g藻类生物质。观察到从小球藻淀粉生产乙醇的产率因子为0.305（g g-1）。基于底物和酶的性质以及底物-酶-微生物相互作用的考虑，建立了描述SSF动力学的数学模型。进行关键实验以进行多响应非线性回归分析，以评估关于总体细胞生长和乙醇产量的模型参数。关于细胞、淀粉、葡萄糖和乙醇的浓度，计算值与实验数据吻合得很好。该模型可用于合理的SSF优化和放大的未来。
ABSTRACT Microalgal starch was harnessed to produce ethanol, a promising alternative fuel, by simultaneous saccharification and fermentation (SSF) which combined the enzymatic hydrolysis of starch to glucose and the fermentation of glucose to ethanol by Saccharomyces cerevisiae in a single step. The starch content was increased in a microalga, Chlorella sp., from 19.3% to 38.2% (w/w) by cycloheximide treatment. Crude amylase with the activity of 40 U mL−1, produced by Aspergillus niger, was used to hydrolyze the microalgal starch. An SSF process was applied for the production of bioethanol using S. cerevisiae, and 0.116 g ethanol/g of algal biomass was produced. It was observed that the yield factor for ethanol production from Chlorella starch was 0.305 (g g−1). A mathematical model was formulated to describe the kinetics of SSF based on considerations of the nature of the substrate and enzyme, and the substrate–enzyme–microorganism interactions. Critical experimentation was performed to conduct multiresponse nonlinear regression analysis to evaluate the model parameters regarding overall cell growth and ethanol production. The calculated values agreed well with experimental data, regarding the concentration of cells, starch, glucose and ethanol. This model can be used for rational SSF optimization and scale-up in future.