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 ).