pH对高温厌氧耗氢产甲烷及微生物群落的影响

doi:10.16085/j.issn.1000-6613.2019-0188

摘要/Abstract

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。

关键词: 耗氢产甲烷, 高温, pH, 比产甲烷活性, 微生物群落

Abstract:

Ex-situ biogas upgrading based on hydrogenotrophic methanogenic process has attracted much attention with the depletion of fossil fuels. This study investigated effects of initial pH on anaerobic hydrogen-consuming methanogenesis and microbial community at 55^oC. Experimental results showed that variations 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 tested conditions at the anaerobic system with H₂/CO₂ as the matrix. Alkaline condition (pH 8.5―9.0) improved the hydrogen consumption, and decreased lag phase of methane production to 6.9h, and methane yield was as high as 19.8mL CH₄ /(gVS?h). High throughput sequencing results further demonstrated that hydrogenotrophic methanogens was the main species. Methanothermobacter, with relative abundance of 90.6%―91.6% was found to dominate under acidic and neutral conditions. While Methanobacterium with relative abundance of 83% was the main species under alkaline condition. Methanomassiliicoccus was also detected, with relative abundance of 7.7%. The relative abundance of Methanobacterium and the enrichment of Methanomassicicoccus might be contributable to the high specific methane activity under alkaline condition.

Key words: hydrogenotrophic methanogenesis, thermophilic, pH, specific methanogenic activity, microbial community

中图分类号:

X701.7

陈露蕊,杜诗云,谢丽. pH对高温厌氧耗氢产甲烷及微生物群落的影响[J]. 化工进展, 2019, 38(08): 3816-3822.

Lurui CHEN,Shiyun DU,Li XIE. Effect of pH on hydrogenotrophic methanogenesis and microbial community under thermophilic condition[J]. Chemical Industry and Engineering Progress, 2019, 38(08): 3816-3822.

图/表 7

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实验体系	pH	HRT	取样周期	测定指标
R1	5.5～6.0	10	24h（气样）/48h（液样）	顶空气体组分、pH、液相VFA
R2	7.0～7.5
R3	8.5～9.0

实验体系	pH	HRT	取样周期	测定指标
R1	5.5～6.0	10	24h（气样）/48h（液样）	顶空气体组分、pH、液相VFA
R2	7.0～7.5
R3	8.5～9.0

实验体系	pH	第78~88天每日平均产甲烷量/mL
R1	5.5～6.0	76.45
R2	7.0～7.5	75.13
R3	8.5～9.0	77.55

实验体系	pH	第78~88天每日平均产甲烷量/mL
R1	5.5～6.0	76.45
R2	7.0～7.5	75.13
R3	8.5～9.0	77.55

比产甲烷活性实验分组	初始pH	λ/h	P/mL CH₄	R/mL CH₄ ?h^-1	SMA/mL CH₄?(gVS)^-1?h^-1
B1	5.5～6.0	17.4	7.5	0.7	8.4
B2	7.0～7.5	8.8	7.1	0.7	9.5
B3	8.5～9.0	6.9	7.3	0.9	19.8