A bacterial strain, designated strain G-1-1-14T, was isolated from Kyonggi University forest soil during a study of previously uncultured bacterium. The cells of strain G-1-1-14T were motile by means of peritrichous flagella, Gram-stain-negative, rod-shaped, and able to grow autotrophically with hydrogen and fix nitrogen. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain G-1-1-14T belonged to the genus Azohydromonas. The closest species of strain G-1-1-14T were Azohydromonas ureilytica UCM-80 T (98.4% sequence similarity), Azohydromonas lata IAM 12599 T (97.5%), Azohydromonas riparia UCM-11 T (97.1%), and Azohydromonas australica IAM 12664 T (97.0%). The genome of strain G-1-1-14T was 6,654,139 bp long with 5,865 protein-coding genes. The genome consisted of N2-fixing genes (nifH) and various regulatory genes for CO2 fixation and H2 utilization. The principal respiratory quinone was ubiquinone-8, and the major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol, and phosphatidylglycerol. The major fatty acids were summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1 ω7c), C16 : 0, summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), and cyclo-C17 : 0. The DNA G + C content was 69.9%. The average nucleotide identity (OrthoANI), in silico DNA-DNA hybridization (dDDH), and conventional DDH relatedness values were below the species demarcation values for novel species. Based on genomic, genetic, phylogenetic, phenotypic, and chemotaxonomic characterizations, strain G-1-1-14T represents a novel species within the genus Azohydromonas, for which the name Azohydromonas caseinilytica sp. nov. is proposed. The type strain is G-1-1-14T (= KACC 21615 T = NBRC 114390 T ).
Keywords: Azohydromonas caseinilytica sp. nov.; CO2 assimilation; N2-fixation; forest soil; next generation sequencing; uncultured bacterium.
Copyright © 2021 Dahal, Chaudhary, Kim and Kim.