Acinetobacter stercoris sp. nov. isolated from output source of a mesophilic german biogas plant with anaerobic operating conditions

The Gram-stain-negative, oxidase negative, catalase positive strain KPC-SM-21(T), isolated from a digestate of a storage tank of a mesophilic German biogas plant, was investigated by a polyphasic taxonomic approach. Phylogenetic identification based on the nearly full-length 16S rRNA gene revealed highest gene sequence similarity to Acinetobacter baumannii ATCC 19606(T) (97.0%). Phylogenetic trees calculated based on partial rpoB and gyrB gene sequences showed a distinct clustering of strain KPC-SM-21(T) with Acinetobacter gerneri DSM 14967(T) = CIP 107464(T) and not with A. baumannii, which was also supported in the five housekeeping genes multilocus sequence analysis based phylogeny. Average nucleotide identity values between whole genome sequences of strain KPC-SM-21(T) and next related type strains supported the novel species status. The DNA G + C content of strain KPC-SM-21(T) was 37.7 mol%. Whole-cell MALDI-TOF MS analysis supported the distinctness of the strain to type strains of next related Acinetobacter species. Predominant fatty acids were C(18:1) ω9c (44.2%), C(16:0) (21.7%) and a summed feature comprising C(16:1) ω7c and/or iso-C(15:0) 2-OH (15.3%). Based on the obtained genotypic, phenotypic and chemotaxonomic data we concluded that strain KPC-SM-21(T) represents a novel species of the genus Acinetobacter, for which the name Acinetobacter stercoris sp. nov. is proposed. The type strain is KPC-SM-21(T) (= DSM 102168(T) = LMG 29413(T)). SUPPLEMENTARY INFORMATION: The online version of this article (10.1007/s10482-021-01517-7) contains supplementary material, which is available to authorized users.