Aetherobacter fasciculatus gen. nov., sp. nov. and Aetherobacter rufus sp. nov., novel myxobacteria with promising biotechnological applications.

Bacterial strains SBSr002T and SBSr003T were isolated in 2007 from dried soil samples containing decaying plant material. The organisms were recognized as myxobacteria by growth-stage characteristics, forming swarming colonies and fruiting bodies on agar and on filter paper. These strains were unusual for their ring-like or halo colony appearance in an agar. Both isolates were characterized as bacteriolytic, non-cellulolytic, mesophilic, aerobic and chemoheterotrophic and showed resistance to various antibiotics. GC-MS analysis of their cellular fatty acids revealed rather large quantities of docosahexaenoic acid, and they also both contained eicosapentaenoic acid, arachidonic acid and docosapentaenoic acid. Strain SBSr003T was previously identified as the producer organism of a novel class of potent antiviral metabolites that were called aetheramides. The G+C content of the genomic DNA was 68.0-68.9 mol%. Phylogenetic analysis revealed that both strains belong within the family Polyangiaceae, suborder Sorangiineae, order Myxococcales. Their 16S rRNA gene sequences showed the highest similarity (97-99 %) to sequences derived from clones of uncultured bacteria, 95-96 % similarity to Byssovorax cruenta and Sorangium cellulosum and 94 % similarity to Chondromyces apiculatus. The results of a polyphasic taxonomic characterization suggested that strains SBSr002T and SBSr003T represent two distinct species of a novel genus, Aetherobacter gen. nov., for which the names Aetherobacter fasciculatus sp. nov. (type strain SBSr002T = DSM 24601T = NCCB 100377T) and Aetherobacter rufus sp. nov. (type strain SBSr003T = DSM 24628T = NCCB 100378T) are proposed. The type species of Aetherobacter is Aetherobacter fasciculatus.