酒精-沼气双发酵耦联工艺提高酒精产量机理解析

Mechanism of ethanol yield increase in the integrated ethanol and methane fermentation process

在酒精-沼气双发酵耦联工艺中,将沼液和酒糟的混合水回用于酒精发酵过程,不仅可为酒精发酵提供氮源,减少外源氮源添加,还可以降低代谢副产物甘油的生成,提高酒精产率。经分析,乙酸铵是混合水中主要的氮源物质。文中比较了乙酸铵与硫酸铵、氯化铵2种氮源物质对酒精发酵的影响,以揭示酒精-沼气双发酵耦联工艺对酒精发酵效果影响的机理。结果表明,相较于其他2种氮源,乙酸铵为氮源时,酒精发酵时间最短、乙醇产率最高、副产物甘油产量最低。这说明酒精-沼气双发酵耦联工艺中混合水中的乙酸铵是提高酒精产率的主要原因。进一步的研究表明,乙酸铵作为氮源对酒精发酵的正面影响的主要原因在于乙酸铵中乙酸根的存在。

In the integrated ethanol and methane fermentation process,the mixture of digestate and stillage was reused as process water for the ethanol fermentation,which could not only provide enough nitrogen sources for ethanol fermentation,but also reduce byproduct glycerol production and enhance ethanol yield. Ammonium acetate was detected as the main nitrogen source in the mixed water. Therefore,in this study,effects of ammonium acetate,ammonium sulfate and ammonium chloride on ethanol fermentation performance were compared to reveal the mechanism for effect of the integrated ethanol and methane fermentation process on ethanol fermentation. Results showed that compared with two other nitrogen sources used in ethanol fermentation,ammonium acetate using as nitrogen source could lead to the shortest fermentation time,the highest ethanol yield and the lowest glycerol production. This indicated that ammonium acetate was the main factor that provided nitrogen source and enhanced ethanol yield in the integrated ethanol and methane fermentation process. Further studies showed that the main reason for the positive effect of ammonium acetate as a nitrogen source on alcoholic fermentation was the presence of acetate in ammonium acetate.