Esikova Tatiana Z, Anokhina Tatiana O, Suzina Nataliya E, Shushkova Tatiana V, Wu Yonghong, Solyanikova Inna P
Laboratory of Plasmid Biology, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Pushchino Center for Biological Research of the Russian Academy of Sciences, Prosp. Nauki 5, Pushchino, 142290 Pushchino, Russia.
Laboratory of Cytology of Microorganisms, G.K. Skryabin Institute of Biochemistry and Physiology of Microorganisms, Pushchino Scientific Center for Biological Research of the Russian Academy of Sciences, Prosp. Nauki 5, Pushchino, 142290 Pushchino, Russia.
Microorganisms. 2023 Mar 3;11(3):650. doi: 10.3390/microorganisms11030650.
In this work, a new Ch2 strain was isolated from soils polluted by agrochemical production wastes. This strain has a unique ability to utilize toxic synthetic compounds such as -caprolactam (CAP) as a sole carbon and energy source and the herbicide glyphosate (GP) as a sole source of phosphorus. Analysis of the nucleotide sequence of the 16S rRNA gene of Ch2 revealed that the strain belongs to the species . This strain grew in the mineral medium containing CAP in a concentration range of 0.5 to 5.0 g/L and utilized 6-aminohexanoic acid and adipic acid, which are the intermediate products of CAP catabolism. The ability of strain Ch2 to degrade CAP is determined by a conjugative megaplasmid that is 550 kb in size. When strain Ch2 is cultured in a mineral medium containing GP (500 mg/L), more intensive utilization of the herbicide occurs in the phase of active growth. In the phase of declining growth, there is an accumulation of aminomethylphosphonic acid, which indicates that the C-N bond is the first site cleaved during GP degradation (glyphosate oxidoreductase pathway). Culture growth in the presence of GP during the early step of its degradation is accompanied by unique substrate-dependent changes in the cytoplasm, including the formation of vesicles of cytoplasmic membrane consisting of specific electron-dense content. There is a debate about whether these membrane formations are analogous to metabolosomes, where the primary degradation of the herbicide can take place. The studied strain is notable for its ability to produce polyhydroxyalkanoates (PHAs) when grown in mineral medium containing GP. At the beginning of the stationary growth phase, it was shown that, the amount and size of PHA inclusions in the cells drastically increased; they filled almost the entire volume of cell cytoplasm. The obtained results show that the strain Ch2 can be successfully used for the PHAs' production. Moreover, the ability of Ch2 to degrade CAP and GP determines the prospects of its application for the biological cleanup of CAP production wastes and in situ bioremediation of soil polluted with GP.
在本研究中，从受农用化学品生产废物污染的土壤中分离出一种新的Ch2菌株。该菌株具有独特的能力，能够利用有毒的合成化合物，如己内酰胺（CAP）作为唯一的碳源和能源，以及除草剂草甘膦（GP）作为唯一的磷源。对Ch2菌株16S rRNA基因的核苷酸序列分析表明，该菌株属于 物种。该菌株在含有浓度为0.5至5.0 g/L的CAP的矿物培养基中生长，并利用己内酰胺分解代谢的中间产物6-氨基己酸和己二酸。Ch2菌株降解CAP的能力由一个大小为550 kb的接合大质粒决定。当Ch2菌株在含有GP（500 mg/L）的矿物培养基中培养时，在活跃生长阶段对除草剂的利用更为强烈。在生长下降阶段，会积累氨基甲基膦酸，这表明C-N键是草甘膦降解（草甘膦氧化还原酶途径）过程中第一个被裂解的位点。在草甘膦降解的早期阶段，在其存在下培养会伴随着细胞质中独特的底物依赖性变化，包括形成由特定电子致密内容物组成的细胞质膜囊泡。关于这些膜结构是否类似于代谢体存在争议，在代谢体中除草剂可进行初步降解。所研究的菌株在含有草甘膦的矿物培养基中生长时能够产生聚羟基脂肪酸酯（PHA），这一点值得注意。在稳定生长期开始时，结果表明，细胞中PHA包涵体的数量和大小急剧增加；它们几乎充满了整个细胞质体积。所得结果表明，Ch2菌株可成功用于生产PHA。此外，Ch2菌株降解CAP和GP的能力决定了其在己内酰胺生产废物生物净化以及草甘膦污染土壤原位生物修复中的应用前景。
