Two heterotrophic bacteroidetes strains were isolated as satellites from autotrophic enrichments inoculated with samples from hypersaline soda lakes in southwestern Siberia. Strain Z-1702 ^T is an obligate anaerobic fermentative saccharolytic bacterium from an iron-reducing enrichment culture, while Ca. Cyclonatronum proteinivorum Omega ^T is an obligate aerobic proteolytic microorganism from a cyanobacterial enrichment. Cells of isolated bacteria are characterized by highly variable morphology. Both strains are chloride-independent moderate salt-tolerant obligate alkaliphiles and mesophiles. Strain Z-1702 ^T ferments glucose, maltose, fructose, mannose, sorbose, galactose, cellobiose, N-acetyl-glucosamine and alpha-glucans, including starch, glycogen, dextrin, and pullulan. Strain Omega ^T is strictly proteolytic utilizing a range of proteins and peptones. The main polar lipid fatty acid in both strains is iso-C _15:0, while other major components are various C ₁₆ and C ₁₇ isomers. According to pairwise sequence alignments using BLAST Gracilimonas was the nearest cultured relative to both strains (<90% of 16S rRNA gene sequence identity). Phylogenetic analysis placed strain Z-1702 ^T and strain Omega ^T as two different genera in a deep-branching clade of the new family level within the order Balneolales with genus. Based on physiological characteristics and phylogenetic position of strain Z-1702 ^T it was proposed to represent a novel genus and species Natronogracilivirga saccharolityca gen. nov., sp. nov. (= DSMZ 109061 ^T =JCM 32930 ^T =VKM B 3262 ^T). Furthermore, phylogenetic and phenotypic parameters of N. saccharolityca and C. proteinivorum gen. nov., sp. nov., strain Omega ^T (=JCM 31662 ^T, =UNIQEM U979 ^T), make it possible to include them into a new family with a proposed designation Cyclonatronaceae fam. nov.