Aridibacter nitratireducens sp. nov., a member of the family Blastocatellaceae, class Blastocatellia, isolated from an African soil.

Members of the class Blastocatellia are frequently found in soils with a neutral and (slightly) basic pH where they constitute an important fraction of the microbial community. A novel representative of the class Blastocatellia was isolated from a Ghanaian soil and was characterized in detail. Cells of strain A24_SHP_-5_238T were non-motile rods that divided by binary fission and formed orange to salmon-coloured colonies on agar plates. Strain A24_SHP_-5_238T tolerated pH values of pH 6.0-9.0 (best growth at pH 7.0-8.5) and temperature values of 8-45 °C (best growth at 33-40 °C). It grew chemo-organoheterotrophically on several sugars, a few amino acids, organic acids and different complex protein substrates. In addition, strain A24_SHP_-5_238T was able to use nitrate as an alternative electron acceptor in the absence of oxygen. Major fatty acids of A24_SHP_-5_238T were iso-C15 : 0, summed feature 1 (C13 : 0 3-OH/iso-C15 : 1 H), summed feature 3 (C16 : 1ω7c/C16 : 1ω6c), anteiso-C17 : 0 and anteiso-C15 : 0. The major quinone was MK-8, and the DNA G+C content was 53.5 mol%. The closest described phylogenetic relatives were Aridibacter famidurans A22_HD_4HT and Aridibacter kavangonensis Ac_23_E3T with a 16S rRNA gene sequence identity of 97.6 and 97.2 %, respectively. The DNA-DNA hybridization values (<28.5 %) confirmed that A24_SHP_-5_238T represents a novel species within the genus Aridibacter. Based on its morphological, physiological and molecular characteristics, we propose the novel species Aridibacter nitratireducens sp. nov. (type strain A24_SHP_-5_238T = DSM 102177T = CECT 9235T).

The first representative of the globally widespread subdivision 6 Acidobacteria,Vicinamibacter silvestris gen. nov., sp. nov., isolated from subtropical savannah soil.

Members of the phylum Acidobacteria are abundant in a wide variety of soil environments. Despite this, previous cultivation attempts have frequently failed to retrieve representative phylotypes of Acidobacteria, which have, therefore, been discovered by culture-independent methods (13175 acidobacterial sequences in the SILVA database version 123; NR99) and only 47 species have been described so far. Strain Ac_5_C6T represents the first isolate of the globally widespread and abundant subdivision 6 Acidobacteria and is described in the present study. Cells of strain Ac_5_C6T were Gram-stain-negative, immotile rods that divided by binary fission. They formed yellow, extremely cohesive colonies and stable aggregates even in rapidly shaken liquid cultures. Ac_5_C6T was tolerant of a wide range of temperatures (12-40 °C) and pH values (4.7-9.0). It grew chemoorganoheterotrophically on a broad range of substrates including different sugars, organic acids, nucleic acids and complex proteinaceous compounds. The major fatty acids of Ac_5_C6T were iso-C17 : 1 ω9c, C18 : 1 ω7c and iso-C15 : 0. Summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c), iso-C17 : 0 and C16 : 0 were also detected. Phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and an unidentified glycolipid were identified as polar lipids. The major quinone was MK-8. The DNA G+C content of Ac_5_C6T was 65.9 mol%. With 16S rRNA gene sequence similarities of 83-84 %, the closest described relatives were Acidicapsa borealis KA1T, Acidobacterium capsulatum 161T, Granulicella pectinovorans TPB6011T, Occallatibacter riparius 277T and Paludibaculum fermentans P105T. According to the morphological, physiological and molecular characteristics, the novel genus Vicinamibacter gen. nov., and the novel species, Vicinamibacter silvestris sp. nov. (type strain Ac_5_C6T = DSM 29464T = LMG 29035T) are proposed.