接种不同菌源的餐厨垃圾发酵代谢途径及产己酸效能分析

ANALYSIS ON FERMENTATION PATHWAY AND CAPROATE PRODUCTION FROM FOOD WASTE BY DIFFERENT INOCULUM

采用活性污泥、颗粒污泥、酒曲以及酒糟接种餐厨垃圾进行发酵产有机酸,比较了4种菌源在批次发酵条件下的溶出、水解和酸化效率。在此基础上,探究了不同电子供体对碳链增长产己酸的影响。结果表明:利用活性污泥接种餐厨垃圾发酵可产生高光学活性L-乳酸(L-乳酸浓度为22.2 g/L,光学活性为82.3%);颗粒污泥接种餐厨垃圾发酵可产生浓度为4.2 g COD/L的己酸,具有较强产己酸能力。以酒曲和酒糟作为接种菌源时,丁酸浓度分别为21.6 g COD/L(酒曲)和20.4 g COD/L(酒糟),丁酸是碳链增长的重要电子受体,利用酒曲和酒糟接种餐厨垃圾发酵具有很强的产己酸潜力;外加电子供体后,酒糟组己酸浓度达到8.8 g COD/L(以乳酸为电子供体),酒曲组己酸浓度可达到10.4 g COD/L(以乙醇为电子供体)。微生物群落分析发现,优势菌群链球菌属(Streptococcus)分别占酒曲组和酒糟组总菌属丰度的80%以及55%,与高浓度己酸的产生有着较强相关性。

Waste activated sludge,granular sludge,distiller’s yeast,and vinasse were inoculated in the food waste fermentation for organic acid production.Batch tests were conducted to compare the solubilization,hydrolysis,and acidification processes using four different inoculums during fermentation.Based on the batch test,we investigated the effect of different electron donors on chain elongation to produce caproate.When activated sludge was used as the inoculum of food waste fermentation,the production of L-lactic acid reached 22.2 g COD/L and its optical activity reached 82.3%.It was an effective way to ferment food waste to produce highly optically active L-lactic acid by inoculating activated sludge.Caproate at a concentration of 4.2 g COD/L was produced by inoculating granular sludge during fermentation,indicating the strong capacity of caproate production of granular sludge.When distiller’s yeast and vinasse were used as the inoculum,high concentration of butyrate(21.6 g COD/L for distiller’s yeast inoculum and 20.4 g COD/L for vinasse inoculum)was obtained,which was the key electron acceptor during chain elongation.The concentration of caproate reached 8.8 g COD/L by inoculating vinasse(lactic acid as the electron donor)and 10.4 g COD/L by inoculating distiller’s yeast(ethanol as the electron donor).Microbial community analysis revealed that Streptococcus was the dominant genus,accounting for 80%and 55%by inoculating distiller’s yeast and vinasse groups,respectively,showing a strong correlation with the production of high concentration caproate.