纤维素乙醇糟液对稻秸猪粪厌氧发酵的促进机制

纤维乙醇生产会伴随产出大量酸性糟液。利用厌氧技术处理糟液存在C/N低、pH值低等难题，采用糟液与秸秆、猪粪混合后厌氧发酵是一种有效的糟液处理途径。秸秆添加糟液后，TS比例为3%，6%和9%时各组产气量分别为627.8、585.6和443.9 mL·g-1 TS，大幅度高于不添加糟液的秸秆对照组产气量292.5 mL·g-1 TS，且嗜氢产甲烷途径增强，甲烷体积分数从低于60%增至70%以上。猪粪添加糟液在较低TS浓度3%时产气量最高676.7 mL·g-1 TS，秸秆和猪粪按TS 1：1的比例混合时添加糟液的产气效果最佳。秸秆添加糟液的最大VFAs比秸秆对照高2.8~4.7倍，产气延迟增加，从混合型发酵变为典型的丁酸型发酵；猪粪添加糟液后VFAs浓度相对较低，产气启动快，从混合型发酵转变为典型的丙酸型发酵，说明糟液在不同碳源条件下，有着不同的代谢促进途径。糟液与农业废弃物混合厌氧发酵，是一种高效的共发酵体系。糟液在刺激促进秸秆、猪粪产气提升和解除抑制风险的同时，自身也得到高效降解利用。

Promotion mechanism of Lignocellulose ethanol vinasse addition on mixed anaerobic fermentation of rice straw and swine manure

Ethanol production via lignocellulose generates a large amount of acid vinasse. Due to the low C/N and pH, the vinasse is difficult to be digested by anaerobic fermentation. While mixed with additional carbon source such as straw and swine manure, the vinasse can be digested effectively in anaerobic co-fermentation system. The biogas yield with substrates of straw mixed with vinasse were 627.8, 585.6 and 443.9 mL·g-1 TS at TS 3%, 6% and 9% respectively, which were much higher than 292.5 mL·g-1 TS in straw control without vinasse addition. The CH4 concentration has improved to above 70% from 60%, indicating the enhancement of methane producing via hydrogenotrophic methanogens by vinasse addition. The highest biogas yield 676.7 mL·g-1 TS with substrate of swine manure mixed with vinasse obtained at TS 3%. For the mixed substrate of straw and manure with vinasse addition, the optimal TS ratio of straw to manure was 1:1, and the highest biogas yield was 425.3 mL·g-1 TS. The maximum VFAs of straw with vinasse group were 2.8 to 4.7 times higher than the straw control group. The lag phase time of biogas production prolonged significantly. The fermentation type turned from mixed type fermentation to typical butyric type fermentation. The VFAs of swine manure with vinasse group was relatively lower, while had shorter lag phase time and the fermentation type changed from mixed fermentation to propionic type. The results showed the biogas enhancement pathway by vinasse supplement was different according to various carbon sources. Mixing with vinasse in the substrate of straw and manure will create a highly efficient anaerobic co-digestion system. The vinasse can effectively stimulate and accelerate the biogas yield of straw and swine manure while the degradation and utilization of itself also can be enhanced efficiently in the co-fermentation.