| 甲烷13C同位素比值表征温度对甲烷生成途径的影响 |
| 摘要点击 2983 全文点击 1278 投稿时间：2007-11-27 修订日期：2008-01-16 |
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| 中文关键词 甲烷碳同位素比值 荧光原位杂交 生活垃圾 厌氧降解 乙酸发酵产甲烷途径 CO2还原产甲烷途径 |
| 英文关键词 stable carbon isotopic signature of CH4 fluorescence in situ hybridization(FISH) household waste anaerobic digestion aceticlastic methanogenesis hydrogenotrophic methanogenesis |
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| 中文摘要 |
| 采用测试气相碳同位素比值的方法比较了中温厌氧降解和高温厌氧降解过程中甲烷（CH4）生成途径的差异，表征了生活垃圾厌氧消化过程CH4生成途径的演变，并结合气液相化学组分和产甲烷菌荧光原位杂交（FISH）分析对同位素表征结果进行了验证.中温（35℃）条件下，垃圾降解初期甲烷13C同位素比值（δ13CH4）下降至-69.5‰，表明此阶段CH4主要产生自CO2还原途径；随着垃圾降解进入快速产CH4阶段，δ13CH4值相应迅速上升至-23.8‰，说明乙酸发酵逐渐成为CH4生成的主要途径，FISH实验结果也发现此阶段以乙酸发酵型产甲烷菌Methanosarcinaceae为主；当产CH4速率逐渐减小进入稳定期时，δ13CH4值迅速降低至-55‰后相对稳定，说明乙酸发酵途径的比例减小，并且维持在较稳定的水平.高温（55℃）条件下，δ13CH4值始终维持在约-70‰，表明甲烷主要由CO2还原作用生成，在快速产CH4阶段，乙酸氧化和CO2还原作用是CH4生成的重要途径. |
| 英文摘要 |
| The methanogenic pathway during anaerobic digestion of household waste was investigated by stable carbon isotopic signature analysis，and testified by the analysis of gas production，leachate characteristics and microbial fluorescence in situ hybridization (FISH) methods.Furthermore，the difference of methanogenic pathway between mesophilic and thermophilic anaerobic digestion was also discussed.Results showed that under mesophilic conditions，the isotopic stable carbon signature of CH4 (δ13CH4) initially decreased to -69.5‰，indicating that CH4 was produced from CO2and H2by hydrogenotrophic methanogens.When active CH4 production phase started，the δ13CH4 values quickly increased to -23.8‰，which indicated more and more CH4 were formed by aceticlastic methanogens，dominantly the family of Methanosarcinaceae，shown by the FISH results.The δ13CH4 values decreased successively and ultimately remained at -55‰，indicating that the fraction of aceticlastic methanogenesis finally decreased to a steady level comparative with CO2-derived methanogenesis at the steady slow methane production phase.Under thermophilic conditions，the δ13CH4 values remained at a level about -70‰，showing that methane were solely produced from CO2reduction，and acetate syntrophic oxidation happened during the active methane production phase. |
