Description of Limnobaculum eriocheiris sp. nov., an intestinal bacterium of Eriocheir sinensis, and reclassification of the genera Jinshanibacter and Insectihabitans as Limnobaculum.

A Gram-stain-negative, aerobic, non-motile and rod-shaped strain, designated LJY008 T , was isolated from the intestinal of Eriocheir sinensis in Pukou base of Jiangsu Institute of Freshwater Fisheries. Strain LJY008 T could grow at 4-37 ℃ (optimum, 30 ℃), pH 6.0-8.0 (optimum, pH 7.0), and with 1.0-6.0% NaCl (w/v; optimum, 1.0%). Strain LJY008 T shared highest 16S rRNA gene sequence similarity with Jinshanibacter zhutongyuii CF-458 T (99.3%), followed by J. allomyrinae BWR-B9 T (99.2%), Insectihabitans xujianqingii CF-1111 T (97.3%), and Limnobaculum parvum HYN0051 T (96.7%). The major polar lipids include phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol. The only respiratory quinone was Q8, and the main fatty acids (> 10%) were C 16:0 , summed feature 3 (C 16:1 ω7c/C 16:1 ω6c), summed feature 8 (C 18:1 ω7c), and C 14:0. The genome-based phylogenies showed that strain LJY008 T was closely associated with members of the genus Jinshanibacter, Insectihabitans, and Limnobaculum. The average nucleotide identities and average amino acid identities (AAI) among strain LJY008 T and closely related neighbours were all below 95%, and the digital DNA-DNA hybridization values among them were all below 36%. The genomic DNA G + C content of strain LJY008 T was 46.1%. Based on the phenotypic, phylogenetic, biochemical and chemotaxonomic analysis, strain LJY008 T represents a novel species of the genus Limnobaculum, for which the name Limnobaculum eriocheiris sp. nov. is proposed. The type strain is LJY008 T (= JCM 34675 T  = GDMCC 1.2436 T  = MCCC 1K06016 T ). In addition, the genera Jinshanibacter and Insectihabitans were reclassified as Limnobaculum, because there was no significant genome-scale divergence or diagnosable difference on phenotypic and chemotaxonomic traits, such as strains of Jinshanibacter and Insectihabitans sharing AAI values of 93.88-94.96%.