Tikhonova Ekaterina N, Suleimanov Ruslan Z, Oshkin Igor Y, Konopkin Aleksey A, Fedoruk Diana V, Pimenov Nikolai V, Dedysh Svetlana N
Winogradsky Institute of Microbiology, Research Center of Biotechnology of the Russian Academy of Sciences, Moscow 119071, Russia.
Microorganisms. 2023 Sep 8;11(9):2257. doi: 10.3390/microorganisms11092257.
Methanotrophic bacteria that possess a unique ability of using methane as a sole source of carbon and energy have attracted considerable attention as potential producers of a single-cell protein. So far, this biotechnology implied using freshwater methanotrophs, although many regions of the world have limited freshwater resources. This study aimed at searching for novel methanotrophs capable of fast growth in saltwater comparable in composition with seawater. A methane-oxidizing microbial consortium containing - and -like methanotrophs was enriched from sediment from the river Chernavka (water pH 7.5, total salt content 30 g L), a tributary river of the hypersaline Lake Elton, southern Russia. This microbial consortium, designated Ch1, demonstrated stable growth on natural gas in a bioreactor in media with a total salt content of 23 to 35.9 g L at a dilution rate of 0.19-0.21 h. The highest biomass yield of 5.8 g cell dry weight (CDW)/L with a protein content of 63% was obtained during continuous cultivation of the consortium Ch1 in a medium with a total salt content of 29 g L. Isolation attempts resulted in obtaining a pure culture of methanotrophic bacteria, strain Ch1-1. The 16S rRNA gene sequence of strain Ch1-1 displayed 97.09-97.24% similarity to the corresponding gene fragments of characterized representatives of , methanotrophs isolated from marine habitats. The genome of strain Ch1-1 was 4.8 Mb in size and encoded 3 rRNA operons, and about 4400 proteins. The genome contained the gene cluster coding for ectoine biosynthesis, which explains the ability of strain Ch1-1 to tolerate high salt concentration.
甲烷营养细菌具有独特的利用甲烷作为唯一碳源和能源的能力，作为单细胞蛋白的潜在生产者已引起了广泛关注。到目前为止，这种生物技术意味着使用淡水甲烷营养菌，尽管世界上许多地区的淡水资源有限。本研究旨在寻找能够在与海水成分相当的盐水中快速生长的新型甲烷营养菌。从俄罗斯南部超咸的埃尔顿湖的支流切尔纳夫卡河（水pH值7.5，总盐含量30 g/L）的沉积物中富集了一个含有 - 和 - 样甲烷营养菌的甲烷氧化微生物群落。这个微生物群落被命名为Ch1，在生物反应器中，在总盐含量为23至35.9 g/L的培养基中，以0.19 - 0.21 h的稀释率，在天然气上表现出稳定的生长。在总盐含量为29 g/L的培养基中对群落Ch1进行连续培养时，获得了最高生物量产量为5.8 g细胞干重（CDW）/L，蛋白质含量为63%。分离尝试得到了甲烷营养细菌的纯培养物，菌株Ch1-1。菌株Ch1-1的16S rRNA基因序列与从海洋栖息地分离的、甲烷营养菌的特征代表的相应基因片段显示出97.09 - 97.24%的相似性。菌株Ch1-1的基因组大小为4.8 Mb，编码3个rRNA操纵子和约4400种蛋白质。该基因组包含编码ectoine生物合成的基因簇，这解释了菌株Ch1-1耐受高盐浓度的能力。
