pH对高温厌氧耗氢产甲烷及微生物群落的影响
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摘要
随着化石燃料的枯竭,以厌氧耗氢产甲烷菌为功能优势菌群的异位(或离位)加氢沼气生物提纯工艺备受关注。本文考察了高温条件下不同初始pH对厌氧耗氢产甲烷过程及微生物群落的影响。研究结果表明,半连续流反应器中不同初始pH变化对产甲烷量影响不大,在以H2/CO2为基质的厌氧体系中,厌氧耗氢产甲烷过程是甲烷产生的主要途径。比产甲烷活性研究结果进一步表明碱性条件(初始pH=8.5～9.0)耗氢产甲烷污泥对氢气消耗率提高,产甲烷迟滞期缩短至6.9h,且甲烷产率高达19.8mL CH4/(gVS?h)。通过高通量测序技术对不同初始pH条件下的产甲烷古菌群落进行分析,3个样本均以厌氧耗氢产甲烷菌为主导,酸性和中性条件古菌群落属水平上相似,以Methanothermobacter为主,其相对丰度分别为90.6%、91.6%;而碱性条件下以Methanobacterium为主,其相对丰度可达83.6%,还发现了Methanomassiliicoccus,其相对丰度可达7.7%。碱性条件下Methanobacterium相对丰度的提高和Methanomassiliicoccus的富集,可能是碱性条件下比产甲烷活性提高的主要原因。
Ex-situbiogas upgrading based on hydrogenotrophic methanogenic process has attractedmuch attention with the depletion of fossil fuels. This study investigated effects of initial p H on anaerobichydrogen-consuming methanogenesis and microbial community at 55 oC. Experimental results showed thatvariations of initial pH did not influence methane production under semi-continuous condition.Hydrogenotrophic methanogenesis was found to be the main pathway of methanogenesis under the testedconditions at the anaerobic system with H2/CO2 as the matrix. Alkaline condition(pH 8.5―9.0) improvedthe hydrogen consumption, and decreased lag phase of methane production to 6.9 h, and methane yieldwas as high as 19.8 mL CH4/(gVS?h). High throughput sequencing results further demonstrated thathydrogenotrophic methanogens was the main species. Methanothermobacter, with relative abundance of90.6%―91.6% was found to dominate under acidic and neutral conditions. While Methanobacterium withrelative abundance of 83% was the main species under alkaline condition. Methanomassiliicoccus was alsodetected, with relative abundance of 7.7%. The relative abundance of Methanobacterium and theenrichment of Methanomassicicoccus might be contributable to the high specific methane activity underalkaline condition.
Ex-situbiogas upgrading based on hydrogenotrophic methanogenic process has attractedmuch attention with the depletion of fossil fuels. This study investigated effects of initial p H on anaerobichydrogen-consuming methanogenesis and microbial community at 55 oC. Experimental results showed thatvariations of initial pH did not influence methane production under semi-continuous condition.Hydrogenotrophic methanogenesis was found to be the main pathway of methanogenesis under the testedconditions at the anaerobic system with H2/CO2 as the matrix. Alkaline condition(pH 8.5―9.0) improvedthe hydrogen consumption, and decreased lag phase of methane production to 6.9 h, and methane yieldwas as high as 19.8 mL CH4/(gVS?h). High throughput sequencing results further demonstrated thathydrogenotrophic methanogens was the main species. Methanothermobacter, with relative abundance of90.6%―91.6% was found to dominate under acidic and neutral conditions. While Methanobacterium withrelative abundance of 83% was the main species under alkaline condition. Methanomassiliicoccus was alsodetected, with relative abundance of 7.7%. The relative abundance of Methanobacterium and theenrichment of Methanomassicicoccus might be contributable to the high specific methane activity underalkaline condition.
引文
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[12] HAO L, LV F, LI L, et al. Self-adaption of methane-producing communities to pH disturbance at different acetate concentrations by shifting pathways and population interaction[J]. Bioresource Technology, 2013, 140(3):319-327.
[13] DRIDI B, RAOULT D, DRANCOURT M. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identification of archaea:towards the universal identification of living organisms[J].APMIS, 2012, 120(2):85-91.
[14]蒋玉双,李桂英. pH值的应用[J].中外医疗, 2001(4):14.JIANG Y S, LI G Y. Application of pH[J]. Friends of Chemical Industry, 2001(4):14.
[2] ULLAH K I, HAFIZ D O M, HASHIM H, et al. Biogas as a renewable energy fuel—A review of biogas upgrading, utilisation and storage[J].Energy Conversion and Management, 2017, 150:277-294.
[3] CHEN Y X, LAVACCHI A, MILLER H A, et al. Nanotechnology makes biomass electrolysis more energy efficient than water electrolysis[J]. Nature Communications, 2014, 5(4036):1-6.
[4] YUSTA J M, ROJAS-ZERPA J C. Renewable and sustainable energy reviews[J]. Renewable&Sustainable Energy Reviews, 2016, 38:834-847.
[5] DEMIREL B, SCHERER P. The roles of acetotrophic and hydrogenotrophic methanogens during anaerobic conversion of biomass to methane:a review[J]. Reviews in Environmental Science and Bio/Technology, 2008, 7(2):173-190.
[6] LAY J, LI Y, NOIKE T. Influences of pH and moisture content on the methane production in high-solids sludge digestion[J]. Water Research, 1997, 31(6):1518-1524.
[7] HAO L, LV F, LI L, et al. Shift of pathways during initiation of thermophilic methanogenesis at different initial pH[J]. Bioresource Technology, 2012, 126(12):418-424.
[8] BU F, DONG N, KHANAL S K, et al. Effects of CO on hydrogenotrophic methanogenesis under thermophilic and extremethermophilic conditions:microbial community and biomethanation pathways[J]. Bioresource Technology, 2018, 266:364-373
[9] KOUGIAS P, TREU L, DANIELA P B, et al. Ex-situ biogas upgrading and enhancement in different reactor systems[J]. Bioresource Technology, 2016, 225:429.
[10] BASSANI I, KOUGIAS P G, TREU L, et al. Biogas upgrading via hydrogenotrophic methanogenesis in two-stage continuous stirred tank reactors at mesophilic and thermophilic conditions[J]. Environmental Science and Technology, 2015, 49(20):12585-12593.
[11] TREU L, KOUGIAS P G, CAMPANARO S, et al. Deeper insight into the structure of the anaerobic digestion microbial community; the biogas microbiome database is expanded with 157 new genomes[J].Bioresource Technology, 2016, 216:260-266.
[12] HAO L, LV F, LI L, et al. Self-adaption of methane-producing communities to pH disturbance at different acetate concentrations by shifting pathways and population interaction[J]. Bioresource Technology, 2013, 140(3):319-327.
[13] DRIDI B, RAOULT D, DRANCOURT M. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry identification of archaea:towards the universal identification of living organisms[J].APMIS, 2012, 120(2):85-91.
[14]蒋玉双,李桂英. pH值的应用[J].中外医疗, 2001(4):14.JIANG Y S, LI G Y. Application of pH[J]. Friends of Chemical Industry, 2001(4):14.