厨余垃圾接种酵母菌固态厌氧发酵产乙醇可行性研究
Feasibility study of solid anaerobic fermentation of kitchen waste inoculation with yeast
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摘要: 厨余垃圾可定向发酵产乙醇,但复杂的预处理导致处理时间长、工艺复杂度增加。本研究通过直接接种酵母菌和灭菌后接种酵母菌对比试验,分析发酵系统内乙醇、乙醇前体物还原糖、还原糖前体物淀粉的降解与产生规律,探讨厨余垃圾直接接种酵母菌固态厌氧发酵产乙醇的可行性及规律。研究结果表明:酵母菌的添加能够促进厨余垃圾固体厌氧发酵产生乙醇,接种酵母菌后乙醇浓度可达11.86~12.09 g/L,比空白组提高了8.41~8.57倍,且高于灭菌预处理后接种的6.88-10.02 g/L;基于Gompertz模型分析也证实该结果,接种酵母菌后,系统产乙醇潜力(Pm)和单位最大乙醇产率(Rm)也随之上升,但接种量未对厨余垃圾Pm和Rm产生大的影响。对乙醇前体物还原糖分析结果表明,接种酵母菌能够在发酵初期就可以发挥作用,促使系统内还原糖0-4 h快速下降为43.37- 46.55 mg/g,从而加速了厨余垃圾的稳定化进程,但在4-24 h内,由于次生代谢物抑制作用,系统内还原糖未出现明显的产生和降解。与此同时,还原糖前体物淀粉水解情况分析结果表明,接种酵母菌可将淀粉的水解率由19.36%提高到27.90-37.57 %,但淀粉含量在274.02-316.51mg/g已不再发生水解,因此,提高淀粉水解产生还原糖成为提升厨余垃圾固态发酵产乙醇的效率亟待解决的难题。Abstract: Kitchen waste can produced ethanol by directional fermentation, but the complex pretreatment leaded to long treatment time and increased process complexity. In this study, through the comparative test of direct inoculation of yeast and inoculation of yeast after sterilization, the degradation and production law of ethanol, ethanol precursor reducing sugar and reducing sugar precursor starch in the fermentation system were analyzed, and the feasibility and law of ethanol production by direct inoculation of kitchen waste with yeast in solid-state anaerobic fermentation were discussed. The results showed that the addition of yeast could promote the solid anaerobic fermentation of kitchen waste to produce ethanol. The ethanol concentration after inoculation with yeast could reach 11.86~12.09 g/L, which was 8.41~8.57 times higher than that of the blank group, and was higher than that of 6.88-10.02 g/L after sterilization pretreatment; The analysis based on Gompertz model also confirmed the results. After inoculation with yeast, the system ethanol production potential (Pm) and unit maximum ethanol yield (Rm) also increased, but the inoculation amount did not have a great impact on the Pm and Rm of kitchen waste. The analysis results of reducing sugar of ethanol precursor showed that inoculating yeast could play a role in the early stage of fermentation, which promoted the rapid decline of reducing sugar in the system to 43.37-46.55 mg/g in 0-4 h, thus accelerating the stabilization process of kitchen waste. However, within 4-24 h, due to the inhibition of secondary metabolites, reducing sugar in the system did not appear obvious production and degradation. At the same time, the analysis results of starch hydrolysis of reducing sugar precursor show that inoculating yeast can increase the hydrolysis rate of starch from 19.36% to 27.90-37.57%, but the hydrolysis will no longer occur when the starch content is 274.02-316.51mg/g. Therefore, improving the efficiency of reducing sugar produced by starch hydrolysis has become an urgent problem to be solved.
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Key words:
- kitchen waste /
- ethanol /
- yeast /
- anaerobic fermentation /
- reducing sugar /
- starch
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