Isolation and Characterization of Halophilic Bacteria of the Halomonadaceae Family, Promising Producers of Extracellular Polysaccharides

Exopolysaccharide (EPS) production is one of the key mechanisms of bacterial survival in hypermineralized environments. Representatives of the Halomonadaceae family are recognized as basic organisms for next-generation industrial biotechnology; however, the range of Halomonas used and information on the structural diversity of their EPSs are rather limited. The results of metagenomic analysis of salt, peloid, and soil samples from the coastal zone of salt lakes in the Volgograd region with subsequent seeding on selective mineral media made it possible to isolate bacteria of the Halomonadaceae family. For taxonomically identified strains, cultivation conditions were optimized and EPSs were obtained, the structure of which was characterized based on chemical analysis data and NMR spectroscopy. The study of the physicochemical properties of EPSs (viscosity, hygroscopicity, emulsifying activity, and antioxidant properties) showed that these polymers are promising for biotechnological applications.