The massive use of polyhexamethylene guanidine(PHMG),as a typical bactericidal agent,raised environmental concerns to the public.This work comprehensively revealed the hormesis effects of PHMG occurred in waste activa...The massive use of polyhexamethylene guanidine(PHMG),as a typical bactericidal agent,raised environmental concerns to the public.This work comprehensively revealed the hormesis effects of PHMG occurred in waste activated sludge(WAS)on the generation of volatile fatty acids(VFAs)during anaerobic fermentation.The low level of PHMG(100 mg/g TSS)significantly promoted the VFAs generation(1283 mg COD/L,compared with 337 mg COD/L in the control)via synchronously facilitating the solubilization,hydrolysis,and acidification steps but inhibiting methanogenesis.Metagenomic analysis showed that the functional anaerobe(i.e.,Bacteroides,Macellibacteroide and Parabacteroide)and corresponding genetic expressions responsible for extracellular hydrolysis(i.e.,clp P),membrane transport(i.e.,ffh and gsp F),intracellular substrates metabolism(i.e.,ald and paa F)and VFAs biosynthesis(i.e.,ACACA and FASN)were enhanced in the optimal presence of PHMG.Moreover,the anaerobic species could respond and adapt to low PHMG stimuli via quorum sensing(i.e.,cqs A,rpf C and rpf G),and thus maintain the high microbial metabolic activities.However,they were unable to tolerate the toxicity of excessive PHMG,resulting in the extremely low VFAs production.This work enlightened the effects of emerging pollutants on WAS fermentation at the genetic levels,and provided guidance on the WAS treatment and resource recovery.展开更多
基金financially supported by the National Natural Science Foundation of China(No.52070069)Jiangsu Province Natural Science Foundation(No.BK20211207)+3 种基金China Postdoctoral Science Foundation(No.2021M692423)Shanghai Post-doctoral Excellence Program(No.2020419)State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF20005)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD),China。
文摘The massive use of polyhexamethylene guanidine(PHMG),as a typical bactericidal agent,raised environmental concerns to the public.This work comprehensively revealed the hormesis effects of PHMG occurred in waste activated sludge(WAS)on the generation of volatile fatty acids(VFAs)during anaerobic fermentation.The low level of PHMG(100 mg/g TSS)significantly promoted the VFAs generation(1283 mg COD/L,compared with 337 mg COD/L in the control)via synchronously facilitating the solubilization,hydrolysis,and acidification steps but inhibiting methanogenesis.Metagenomic analysis showed that the functional anaerobe(i.e.,Bacteroides,Macellibacteroide and Parabacteroide)and corresponding genetic expressions responsible for extracellular hydrolysis(i.e.,clp P),membrane transport(i.e.,ffh and gsp F),intracellular substrates metabolism(i.e.,ald and paa F)and VFAs biosynthesis(i.e.,ACACA and FASN)were enhanced in the optimal presence of PHMG.Moreover,the anaerobic species could respond and adapt to low PHMG stimuli via quorum sensing(i.e.,cqs A,rpf C and rpf G),and thus maintain the high microbial metabolic activities.However,they were unable to tolerate the toxicity of excessive PHMG,resulting in the extremely low VFAs production.This work enlightened the effects of emerging pollutants on WAS fermentation at the genetic levels,and provided guidance on the WAS treatment and resource recovery.
