The occurrence and activity of aerobic methanotrophs are influenced by environmental conditions, including pH, temperature, salinity, methane and oxygen concentrations, and nutrient availability. Aerobic methanotrophs synthesize a variety of lipids important for cell functions. However, culture-based experiments studying the influence of environmental parameters on lipid production by aerobic methanotrophs are scarce. Such information is crucial to interpret lipid patterns of methanotrophic bacteria in the environment. In this study, the alkaliphilic strain Methylotuvimicrobium alcaliphilum was cultivated under different salinities and different nitrate concentrations to assess the effect of changing conditions on the inventory of pentacyclic triterpenoids. The results indicate that hopanoid abundance is enhanced at lower salinity and higher nitrate concentration. The production of most pentacyclic triterpenoids was favored at low salinity, especially for aminotriol. Interestingly, 3-methyl-aminotetrol and tetrahymanol were favored at higher salinity. Bacteriohopanepolyols (BHPs), particularly aminotriol and 3-methyl-aminotriol, increased considerably at higher nitrate concentrations. Four novel N-containing BHPs—aminodiol, 3-methyl-aminodiol, and isomers of aminotriol and 3-methyl-aminotriol—were identified. This study highlights the significance of environmental factors for bacterial lipid production and documents the need for cultivation studies under variable conditions to utilize the full potential of the biomarker concept.

好氧甲烷氧化菌的发生和活性受环境条件的影响，这些环境条件包括pH值，温度，盐度，甲烷和氧气的浓度以及养分的利用率。好氧甲烷氧化菌合成多种对细胞功能重要的脂质。然而，基于文化的实验研究了环境参数对好氧甲烷氧化菌生产脂质的影响。这些信息对于解释环境中甲烷营养细菌的脂质模式至关重要。在这项研究中，嗜碱菌株Alcaliphilum在不同的盐度和不同的硝酸盐浓度下种植大豆，以评估不断变化的条件对五环三萜类化合物库存的影响。结果表明，在较低的盐度和较高的硝酸盐浓度下，类胡萝卜素的丰度增加。在低盐度下，大多数五环三萜类化合物的生产受到青睐，尤其是对于氨基三醇而言。有趣的是，较高的盐度有利于3-甲基-氨基四醇和四氢香醇。在较高的硝酸盐浓度下，细菌型庚烷多元醇（BHP），尤其是氨基三醇和3-甲基-氨基三醇显着增加。四个小说N确定了含BHP的化合物-氨基二醇，3-甲基-氨基二醇以及氨基三醇和3-甲基-氨基三醇的异构体。这项研究突出了环境因素对细菌脂质生产的重要性，并记录了在可变条件下进行培养研究以利用生物标志物概念的全部潜力的需求。