甲烷氧化菌分类及代谢途径研究进展

Progresses in the classification and mechanism of methane-oxidizing bacteria

甲烷作为仅次于二氧化碳的第2号温室气体,是全球温室效应的主要"贡献者"之一。甲烷氧化菌是一类可以直接以甲烷作为能源和碳源的微生物,不仅能减少土壤甲烷排放量,在含水量不饱和的土壤中还能利用空气中的甲烷,对于减缓全球温室效应具有显著效果。甲烷氧化菌可分为好氧甲烷氧化菌和厌氧甲烷氧化菌2大类,均在环境中分布广泛。本文总结了近年来有关甲烷氧化菌分类及其代谢途径2个方面的最新研究进展,以期为甲烷氧化菌在环境中的生态分布研究及甲烷氧化菌在工程中的应用提供参考。

Methane（CH4）as a colorless,odorless organic gas,is one of the most simple hydrocarbons and is widely distributed in environment.As the second most important greenhouse gas,only following carbon dioxide,methane contributes a lot to the global warming.Methane-oxidizing bacteria are a kind of microorganisms which directly use methane as carbon and energy source.Because they can convert methane into carbon dioxide and mitigate the global greenhouse effect,methaneoxidizing bacteria are attracting more and more attention.Methane-oxidizing bacteria not only reduce methane emissions in the soil,but also uptake the methane in the gas phase of the unsaturated soil.They are important to mitigate the global greenhouse effect.According to whether can uptake oxygen in environment as the electron acceptor or not,methane-oxidizing bacteria can be divided into aerobic and anaerobic methane-oxidizing bacteria.Aerobic methane-oxidizing bacteria are gram-negative bacteria,which use methane as carbon and energy source,have been discovered as early as 1906.Because of the potential value of aerobic methane-oxidizing bacteria in practice production,scientists have made extensive research about them in the past 40 years.At the same time,aerobic methane-oxidizing bacteria can reducesoil methane emissions and uptake methane in the atmosphere,playing an important role in global carbon cycle.Because anaerobic methane-oxidizing bacteria＇s doubling time is long,research progress about them is slow.Cellular components of different kinds of methane-oxidizing bacteria are different,and they have different enzymes and C1 metabolic pathways.The center metabolic mechanism of C1 component determines the competition ability of different bacteria in different environments.The main center metabolic mechanism can be divided into three categories：ribulose monophosphate cycle,serine cycle,and the Calvin-Benson-Bassham cycle.