产甲烷抑制剂氯仿对污泥厌氧消化中同型产乙酸作用的影响
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摘要
厌氧消化是城市污泥常用的资源化处理方式,添加产甲烷抑制剂得到的发酵产物乙酸相比于甲烷被认为更具附加值.同型产乙酸途径是污泥厌氧发酵产乙酸途径之一,然而产甲烷抑制剂的存在对其影响尚不明确,这对污泥厌氧发酵产酸工艺的优化和应用至关重要.本文研究了不同氯仿浓度抑制产甲烷条件下挥发性脂肪酸、气体浓度及同型产乙酸菌和总细菌数量的变化,基于乙酸的稳定性碳同位素分馏效应分析了不同温度条件下氯仿对同型产乙酸作用的影响.结果显示,0.1%和0.5%(V/V)氯仿浓度条件下最高乙酸浓度分别为24.5和22.4 mmol·L~(-1),远低于对照组的52.6 mmol·L~(-1).氯仿抑制产甲烷条件下乙酸的稳定碳同位素丰度δ~(13)C值均高于污泥有机质的δ~(13)C值,50℃时乙酸的δ~(13)C值最高,且同型产乙酸菌相对丰度也低于15和30℃条件下.可见,产甲烷抑制剂氯仿同时能够抑制同型产乙酸作用,0.5%浓度下的抑制效果高于0.1%浓度下,且50℃条件下其抑制作用强于15和30℃条件下.
Anaerobic digestion is a widely used treatment method for resource recycling from sewage sludge. Fermentation product acetate which are more value-added than methane could be obtained under methanogenic inhibition condition. Homoacetogenesis is one of the acetate-producing pathways during anaerobic digestion of sewage sludge. However, the effect of methanogenic inhibitors on homoacetogenesis has not been well understood, which is crucial for the optimization and application of sludge anaerobic digestion process for acetate production. In this study, the change of volatile fatty acids, gas concentration, homoacetogenic bacteria number and its abundance in total bacteria were investigated in the sludge anaerobic digestion under methanogenic inhibition by different concentrations of chloroform. The effect of chloroform on homoacetogenesis under different temperatures was also analyzed based on the stable carbon isotope fractionation of acetate. The maximum acetate concentration was 24.5 and 22.4 mmol·L~(-1) for 0.1% and 0.5%(V/V) of chloroform treatments, respectively, which were much lower than that of the control(52.6 mmol·L~(-1)). The δ~(13)C values of acetate of chloroform treatments were all higher than that of sludge organic matter with the highest δ~(13)C_(acetate) at 50 ℃, and the relative abundance of homoacetogens was also lower than that of 15 and 30 ℃. The results indicated that the methanogenic inhibitor chloroform also inhibited homoacetogenesis in sludge anaerobic digestion with stronger inhibitory effect of 0.5% concentration than 0.1%, and the inhibition at 50 ℃ was stronger than 15 and 30 ℃.
Anaerobic digestion is a widely used treatment method for resource recycling from sewage sludge. Fermentation product acetate which are more value-added than methane could be obtained under methanogenic inhibition condition. Homoacetogenesis is one of the acetate-producing pathways during anaerobic digestion of sewage sludge. However, the effect of methanogenic inhibitors on homoacetogenesis has not been well understood, which is crucial for the optimization and application of sludge anaerobic digestion process for acetate production. In this study, the change of volatile fatty acids, gas concentration, homoacetogenic bacteria number and its abundance in total bacteria were investigated in the sludge anaerobic digestion under methanogenic inhibition by different concentrations of chloroform. The effect of chloroform on homoacetogenesis under different temperatures was also analyzed based on the stable carbon isotope fractionation of acetate. The maximum acetate concentration was 24.5 and 22.4 mmol·L~(-1) for 0.1% and 0.5%(V/V) of chloroform treatments, respectively, which were much lower than that of the control(52.6 mmol·L~(-1)). The δ~(13)C values of acetate of chloroform treatments were all higher than that of sludge organic matter with the highest δ~(13)C_(acetate) at 50 ℃, and the relative abundance of homoacetogens was also lower than that of 15 and 30 ℃. The results indicated that the methanogenic inhibitor chloroform also inhibited homoacetogenesis in sludge anaerobic digestion with stronger inhibitory effect of 0.5% concentration than 0.1%, and the inhibition at 50 ℃ was stronger than 15 and 30 ℃.
引文
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Ji Y,Liu P,Conrad R.2018.Change of the pathway of methane production with progressing anoxic incubation of paddy soil[J].Soil Biology & Biochemistry,121:177-184
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Lee W S,Chua A S M,Yeoh H K,et al.2014.A review of the production and applications of waste-derived volatile fatty acids[J].Chemical Engineering Journal,235:83-99
Liu H,Wang J,Wang A,et al.2011.Chemical inhibitors of methanogenesis and putative applications[J].Applied Microbiology & Biotechnology,89(5):1333-1340
Mach V,Blaser M B,Claus P,et al.2015.Methane production potentials,pathways,and communities of methanogens in vertical sediment profiles of river Sitka[J].Frontiers in Microbiology,6:506
马琳.2012.厌氧消化反应器中同型产乙酸菌产乙酸机制研究[D].无锡:江南大学.10-12
Nie Y Q,Liu H,Du G C,et al.2007.Enhancement of acetate production by a novel coupled syntrophic acetogenesis with homoacetogenesis process[J].Process Biochemistry,42(4):599-605
Ryan P,Forbes C,Colleran E.2008.Investigation of the divisity of homoacetogenic bacteria in mesophilic and thermophilic anaerobic sludges using the formyltetrahydrofolate synthetase gene[J].Water Science & Technology,57(5):675-680
Vavilin V A,Rytov S V,Lokshina L Y.2018.Modelling the specific pathway of CH4 and CO2 formation using carbon isotope fractionation:an example for a boreal mesotrophic fen[J].Isotopes in Environmental & Health Studies,54(5):475-493
Wood H G,Ljungdahl L G.1991.Autotrophic character of the acetogenic bacteria[J].Variations in Autotrophic Life,1:201-250
Xu K W,He L,Jian C.2010a.Effect of classic methanogenic inhibitors on the quantity and diversity of archaeal community and the reductive homoacetogenic activity during the process of anaerobic sludge digestion[J].Bioresource Technology,101(8):2600-2607
Xu K,Liu H,Li X,et al.2010b.Typical methanogenic inhibitors can considerably alter bacterial populations and affect the interaction between fatty acid degraders and homoacetogens[J].Applied Microbiology & Biotechnology,87(6):2267-2279
Xu S,Fu B,Zhang L,et al.2015.Bioconversion of H2/CO2 by acetogen enriched cultures for acetate and ethanol production:the impact of pH[J].World Journal of Microbiology and Biotechnology,31(6):941-950
Ye R,Jin Q,Bohannan B,et al.2014.Homoacetogenesis:A potentially underappreciated carbon pathway in peatlands[J].Soil Biology & Biochemistry,68(1):385-391
Blaser M,Conrad R.2016.Stable carbon isotope fractionation as tracer of carbon cycling in anoxic soil ecosystems[J].Current Opinion in Biotechnology,41:122-129
Blaser M B,Dreisbach L K,Conrad R.2013.Carbon isotope fractionation of 11 acetogenic strains grown on H2 and CO2[J].Applied & Environmental Microbiology,79(6):1787-1794
Braga J K,Soares L A,Motteran F,et al.2016.Effect of 2-bromoethanesulfonate on anaerobic consortium to enhance hydrogen production utilizing sugarcane bagasse[J].International Journal of Hydrogen Energy,41(48):22812-22823
Chidthaisong A,Conrad R.2000.Specificity of chloroform,2-bromoethanesulfonate and fluoroacetate to inhibit methanogenesis and other anaerobic processes in anoxic rice field soil[J].Soil Biology & Biochemistry,32(7):977-988
Conrad R,Claus P,Chidthaisong A,et al.2014.Stable carbon isotope biogeochemistry of propionate and acetate in methanogenic soils and lake sediments[J].Organic Geochemistry,73(3):1-7
Conrad R.2008.Temperature Effects on Methanogenic Microbial Communities//Liu S J,Drake H L.Microbes and the Environment:Perspectives and Challenges[M].Beijing:Science Press.35-40
Drake H L,G??ner A S,Daniel S L.2008.Old acetogens,new light[J].Annals of the New York Academy of Sciences,1125(1):100-128
Freude C,Blaser M.2016.Carbon isotope fractionation during catabolism and anabolism in acetogenic bacteria growing on different substrates[J].Applied & Environmental Microbiology,82(9):2728-2737
H?drich A,Heuer V B,Herrmann M,et al.2012.Origin and fate of acetate in an acidic fen[J].FEMS Microbiology Ecology,81(2):339-354
Ho D,Jensen P,Batstone D.2014.Effects of temperature and hydraulic retention time on acetotrophic pathways and performance in high-rate sludge digestion[J].Environmental Science & Technology,48(11):6468-6476
Ji Y,Liu P,Conrad R.2018.Change of the pathway of methane production with progressing anoxic incubation of paddy soil[J].Soil Biology & Biochemistry,121:177-184
Kotsyurbenko O R,Glagolev M V,Nozhevnikova A N,et al.2001.Competition between homoacetogenic bacteria and methanogenic archaea for hydrogen at low temperature[J].FEMS Microbiology Ecology,38(2/3):153-159
Lee W S,Chua A S M,Yeoh H K,et al.2014.A review of the production and applications of waste-derived volatile fatty acids[J].Chemical Engineering Journal,235:83-99
Liu H,Wang J,Wang A,et al.2011.Chemical inhibitors of methanogenesis and putative applications[J].Applied Microbiology & Biotechnology,89(5):1333-1340
Mach V,Blaser M B,Claus P,et al.2015.Methane production potentials,pathways,and communities of methanogens in vertical sediment profiles of river Sitka[J].Frontiers in Microbiology,6:506
马琳.2012.厌氧消化反应器中同型产乙酸菌产乙酸机制研究[D].无锡:江南大学.10-12
Nie Y Q,Liu H,Du G C,et al.2007.Enhancement of acetate production by a novel coupled syntrophic acetogenesis with homoacetogenesis process[J].Process Biochemistry,42(4):599-605
Ryan P,Forbes C,Colleran E.2008.Investigation of the divisity of homoacetogenic bacteria in mesophilic and thermophilic anaerobic sludges using the formyltetrahydrofolate synthetase gene[J].Water Science & Technology,57(5):675-680
Vavilin V A,Rytov S V,Lokshina L Y.2018.Modelling the specific pathway of CH4 and CO2 formation using carbon isotope fractionation:an example for a boreal mesotrophic fen[J].Isotopes in Environmental & Health Studies,54(5):475-493
Wood H G,Ljungdahl L G.1991.Autotrophic character of the acetogenic bacteria[J].Variations in Autotrophic Life,1:201-250
Xu K W,He L,Jian C.2010a.Effect of classic methanogenic inhibitors on the quantity and diversity of archaeal community and the reductive homoacetogenic activity during the process of anaerobic sludge digestion[J].Bioresource Technology,101(8):2600-2607
Xu K,Liu H,Li X,et al.2010b.Typical methanogenic inhibitors can considerably alter bacterial populations and affect the interaction between fatty acid degraders and homoacetogens[J].Applied Microbiology & Biotechnology,87(6):2267-2279
Xu S,Fu B,Zhang L,et al.2015.Bioconversion of H2/CO2 by acetogen enriched cultures for acetate and ethanol production:the impact of pH[J].World Journal of Microbiology and Biotechnology,31(6):941-950
Ye R,Jin Q,Bohannan B,et al.2014.Homoacetogenesis:A potentially underappreciated carbon pathway in peatlands[J].Soil Biology & Biochemistry,68(1):385-391