sp. nov., a salt-tolerant member of the family isolated from a mesophilically operated biogas fermenter fed with maize silage.

In this work, we succeeded in the isolation of a novel species out of a mesophilically operated biogas fermenter fed with maize silage. Strains GS7-6-2, GS-7K2 and GS-0K3 were isolated from three individual enrichment cultures. 16S rRNA gene sequence comparisons indicated that the isolates had 100 % sequence identity and were most closely related to WN036, with which they shared a 16S rRNA gene sequence similarity of 93.1 %. As a representative, strain GS7-6-2 was further characterized. Strain GS7-6-2 was mesophilic with its growth optimum at 30 °C and a pH range from pH 5.5 to 9.5 (optimum, pH 6.0-8.5). Cells were spherical and sometimes arranged into short chains. Growth was possible with up to 3.6 % (w/v) NaCl, but best without additional NaCl. Strain GS7-6-2 produced butyric acid and acetic acid as main fermentation products while growing on GS2 medium. The major cellular fatty acids were Cω7, C and Cω9. The Gram-stain result was negative. The DNA G+C content was 32.8 mol%. Strain GS7-6-2 was able to ferment 16 (comprising four carbohydrates, five amino acids, four organic acids and three nucleotides) out of the 95 tested substrates. Due to the ecological, genetic and phenotypic differences from the most closely affiliated and validly named organism, WN036, the isolates represent a novel species within the genus , family , for which the name sp. nov. is proposed. The type strain is GS7-6-2 (=DSM 107952=CECT 9705).