Methanotrophic bacteria can use methane as sole carbon and energy source. Its importance in the environment is related to the mitigation of methane emissions from soil and water to the atmosphere. Brazilian mangroves are highly productive, have potential to methane production, and it is inferred that methanotrophic community is of great importance for this ecosystem. The scope of this study was to investigate the functional and taxonomic diversity of methanotrophic bacteria present in the anthropogenic impacted sediments from Bertioga´s mangrove (SP, Brazil). Sediment sample was cultivated with methane and the microbiota actively involved in methane oxidation was identified by DNA-based stable isotope probing (DNA-SIP) using methane as a labeled substrate. After 4 days (96 h) of incubation and consumption of 0.7 mmol of methane, the most active microorganisms were related to methanotrophs Methylomonas and Methylobacter as well as to methylotrophic Methylotenera, indicating a possible association of these bacterial groups within a methane-derived food chain in the Bertioga mangrove. The abundance of genera Methylomonas, able to couple methane oxidation to nitrate reduction, may indicate that under low dissolved oxygen tensions, some aerobic methanotrophs could shift to intraerobic methane oxidation to avoid oxygen starvation.

甲烷营养细菌可以使用甲烷作为唯一的碳源和能源。它在环境中的重要性与减少从土壤和水向大气的甲烷排放有关。巴西红树林生产力高，具有产生甲烷的潜力，据推测，甲烷营养群落对该生态系统非常重要。本研究的范围是调查存在于来自 Bertioga 红树林（SP，巴西）的人为影响沉积物中的甲烷营养细菌的功能和分类多样性。沉积物样品与甲烷一起培养，并通过使用甲烷作为标记底物的基于 DNA 的稳定同位素探测 (DNA-SIP) 来鉴定积极参与甲烷氧化的微生物群。经过 4 天（96 小时）的孵化和消耗 0.7 mmol 的甲烷，Methylomonas和Methylobacter以及甲基营养型Methylotenera，表明这些细菌群可能与 Bertioga 红树林中甲烷衍生的食物链有关。能够将甲烷氧化与硝酸盐还原结合起来的甲基单胞菌属的丰富程度可能表明，在低溶解氧张力下，一些需氧甲烷氧化菌可能会转向需氧内甲烷氧化以避免缺氧。