Understanding the impact of allicin for organic matter release and microorganism community in anaerobic co-digestion of food waste and waste activated sludge

Allicin as an active component in allium species being widely present in food waste (FW) and waste activated sludge (WAS). Recently, allicin has been found to inhibit the anaerobic co-digestion. However, few literatures were available related to its impacting on organic matter release and microbial community in anaerobic co digestion system of FW and WAS. Thus, this work aimed to fill that gap through use a series of batch test under conditions of pH 7 and 35 +/- 1 degrees C. Experimental results showed that the anaerobic co-digestion system almost could not measure methane accumulation before day 20, when allicin dosage was 2.0 mu g/L. However, the amount of intracellular material released from FW and WAS to substrate liquid was raised, including organic matter, PO43--P and NH4+-N. Analysis of microbial community based on high throughput sequencing showed that microbial diversity increased at initial phase of anaerobic co-digestion from FW and WAS, meanwhile, community abundance of Candidatus_Methanofastidiosum raised significantly with co-digestion time. Whereas, methanosaeta abundance was only 19.74% in the allicin test reactor that it was the highest abundance in blank group. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

Allicin, an active component in garlic species, is found to inhibit anaerobic co-digestion, leading to minimal methane accumulation in the system. However, the release of intracellular material and increase in microbial diversity were observed in the presence of allicin.