As a frequently used product with antimicrobial activity,consumed allicin might be dis-charged and concentrated in waste-activated sludge(WAS).However,the influence of al-licin(as an exogenous pollutant)on WAS fermentation has not been clearly revealed.This study aimed to disclose the impacts of allicin on volatile fatty acid(VFA)generation dur-ing WAS fermentation.The results showed that the appropriate presence of allicin(10 mg/g TSS)significantly enhanced the VFA yield(1894 versus 575 mg COD/L in the control)with increased acetate proportion(24.3％).Further exploration found that allicin promoted WAS solubilization,hydrolysis and acidification simultaneously.Metagenomic analysis revealed that the key genes involved in extracellular hydrolysis metabolism(i.e.,CAZymes),mem-brane transport(i.e.,gtsA and ytfT),substrate metabolism(i.e.,yhdR and pfkC)and fatty acid synthesis(i.e.,accA and accD)were all highly expressed.Allicin also induced the bacteria to produce more signalling molecules and regulate cellular functions,thereby enhancing the microbial adaptive and regulatory capacity to the unfavourable environment.Moreover,the variations in fermentative microbes and their contributions to the upregulation of func-tional genes(i.e.,ytfR,gltL,INV,iolD and pflD)for VFA generation were disclosed.Overall,the simultaneous stimulation of functional microbial abundances and metabolic activities contributed to VFA production in allicin-conditioned reactors.

Feng Wang;Jingyang Luo;Shiyu Fang;Wenxuan Huang;Yunqi Zhang;Le Zhang;Xiaoshi Cheng;Wei Du;Fang Fang;Jiashun Cao;Yang Wu

Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes,Ministry of Education,Hohai University,Nanjing 210098,China;College of Environment,Hohai University,Nanjing 210098,China;State Key Laboratory of Pollution Control and Resource Reuse,School of Environmental Science and Engineering,Tongji University,Shanghai 200092,China

环境科学学报（英文版）

[1]Feng Wang;Jingyang Luo;Shiyu Fang;Wenxuan Huang;Yunqi Zhang;Le Zhang;Xiaoshi Cheng;Wei Du;Fang Fang;Jiashun Cao;Yang Wu-.Mechanisms of allicin exposure for the sludge fermentation enhancement:Focusing on the fermentation processes and microbial metabolic traits)[J].环境科学学报（英文版）,2022(05):253-264

licin,gtsA,ytfT,yhdR,pfkC,accA,ytfR,gltL,iolD,pflD

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