Aerobic methane-oxidizing bacteria, or methanotrophs, play a crucial role in the global methane cycle. Their methane oxidation activity in various environmental settings has a great mitigation effect on global climate change. Alphaproteobacterial methanotrophs were among the first to be taxonomically characterized, nowadays unified in the Methylocystaceae and Beijerinckiaceae families. Originally thought to have an obligate growth requirement for methane and related one-carbon compounds as a source of carbon and energy, it was later shown that various alphaproteobacterial methanotrophs are facultative, able to grow on multicarbon compounds such as acetate. Most recently, we expanded our knowledge of the metabolic versatility of alphaproteobacterial methanotrophs. We showed that Methylocystis strain SC2 has the capacity for mixotrophic growth on H2 and CH4. This mini-review will summarize the change in perception from the long-held paradigm of obligate methanotrophy to today`s recognition of alphaproteobacterial methanotrophs as having both facultative and mixotrophic capabilities.

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Alphaproteobacteria 中 II 型甲烷氧化菌的意外代谢多功能性

需氧甲烷氧化细菌或甲烷氧化菌在全球甲烷循环中起着至关重要的作用。它们在各种环境环境中的甲烷氧化活动对全球气候变化有很大的缓解作用。Alphaproteobacterial methanotrophs 是最早被分类特征的，现在统一在 Methylocystaceae 和 Beijerinckiaceae 科中。最初认为甲烷和相关的单碳化合物作为碳和能量的来源有一定的生长要求，后来证明各种 α-变形菌甲烷氧化菌是兼性的，能够在多碳化合物（如醋酸盐）上生长。最近，我们扩展了对 alphaproteobacterial 甲烷氧化菌的代谢多功能性的了解。我们表明 Methylocystis 菌株 SC2 具有在 H2 和 CH4 上混合营养生长的能力。这篇简短的评论将总结从长期坚持的专性甲烷营养模式到今天对 alphaproteobacterial 甲烷氧化菌同时具有兼性和混合营养能力的认知的变化。