好氧甲烷氧化菌生理生态特征及其在自然湿地中的群落多样性研究进展  

A review of the physiological and ecological characteristics of methanotrophs and methanotrophic community diversity in the natural wetlands

作　　者：邓永翠[1,2] 车荣晓[1] 吴伊波[3] 王艳芬[1] 崔骁勇[1] 

机构地区：[1]中国科学院大学,北京100049 [2]南京师范大学虚拟地理环境教育部重点实验室,南京210046 [3]宁波大学,宁波315211

出　　处：《生态学报》2015年第14期4579-4591,共13页Acta Ecologica Sinica

基　　金：国家自然基金项目资助(11079053;31200367)

摘　　要：甲烷氧化菌是一类可以利用甲烷作为唯一碳源和能源的细菌,在全球变化和整个生态系统碳循环过程中起着重要的作用。近年来,对甲烷氧化菌的生理生态特征及其在自然湿地中的群落多样性研究取得了较大进展。在分类方面,疣微菌门、NC10门及两个丝状菌属甲烷氧化菌的发现使其分类体系得到了进一步的完善;在单加氧酶方面,发现甲烷氧化菌可以利用pM MO和sM MO两种酶进行氧化甲烷的第一步反应,Ⅱ型甲烷氧化菌中pM MO2的发现证实甲烷氧化菌可以利用这种酶氧化低浓度的甲烷;在底物利用方面,已经发现了越来越多的兼性营养型甲烷氧化菌,证实它们可以利用的底物比之前认为的更广泛,其中包括乙酸等含有碳碳键的化合物;在生存环境方面,能在不同温度、酸度和盐度的环境中生存的甲烷氧化菌不断被分离出来。全球自然湿地甲烷氧化菌群落多样性的研究目前主要集中在北半球高纬度的酸性泥炭湿地,Ⅱ型甲烷氧化菌Methylocystis、Methylocella和Methylocapsa是这类湿地主要的甲烷氧化菌类群,尤其以Methylocystis类群最为广泛,而Ⅰ型甲烷氧化菌尤其是Methylobacter在北极寒冷湿地中占优势。随着高通量测序时代的到来和新的分离技术的发展,对甲烷氧化菌的现有认识将面临更多的挑战和发展。Methanotrophs are a group of bacteria that can use methane as their sole source of carbon and energy. They play a major role in carbon cycle and global warming by controlling emissions of methane, the second most important greenhouse gas following CO2. In this review, we summarize recent progress on the physiology, phylogeny, and ecology of methanotrophs, with particular focus on the diversity of methanotrophic community in natural wetlands. The traditionally identified methanotrophs all belong to the phylum Proteobacteria. Based on intracytoplasmic membranes formation, predominant fatty acid types, the mechanism by which carbon is assimilated into biomass and phylogenetic characteristics, proteobacterial methanotrophs are divided into two groups, type Ⅰ and type Ⅱ （Gamma- and Alpha-proteobacteria,respectively）. Up to now, 20 methanotrophic genera have been affiliated in phylum Proteobacteria, including two filamentous methanotrophs, Crenothrix polyspora and Clonothrix fusca. These two species have been characterized recently and form a new branch within the family Methylococcaceae. Verrucomicrobial methanotrophs, a remarkable new finding, are distantly related to the proteobacteria methanotrophs. They have been isolated from geothermal sites, seem to be restricted to extreme environments and form a new genus （Methylacidiphilum）. Methanotrophs are also found in a novel phylum named NC10, which represents bacteria capable of aerobic methane oxidation coupled to denitrification under anoxic conditions. Two types of enzyme, a particulate methane monooxygenase （pMMO） and a soluble methane monooxygenase （sMMO） can be used by methanotrophs to execute the first step of methane oxidation. All known methanotrophs possess the pMMO, except genera Methylocella and Methyloferula which only have sMMO. Some methanotrophs of type Ⅰ and Ⅱ have both pMMO and sMMO. A different pMMO （pMMO2） is discovered in some type Ⅱ methanotrophs, pMMO2 has lower methane oxidation kinetics and enables these methanotr

关 键 词：甲烷氧化菌 甲烷 甲烷单加氧酶 湿地 

分 类 号：Q938[生物学—微生物学]