Gaiella occulta gen. nov., sp. nov., a novel representative of a deep branching phylogenetic lineage within the class Actinobacteria and proposal of Gaiellaceae fam. nov. and Gaiellales ord. nov.

Two isolates, with an optimum growth temperature of about 35–37 °C and an optimum pH for growth between 6.5 and 7.5, were recovered from a deep mineral water aquifer in Portugal. Strains form rod-shaped cells and were non-motile. These strains were non-pigmented, strictly aerobic, catalase and oxidase positive. Strains F2-233T and F2-223 assimilated carbohydrates, organic acids and amino acids. Major fatty acids were novel iso internally branched such as 17:0 iso 10-methyl, 17:0 iso and 15:0 iso 8-methyl. The peptidoglycan contained meso-diaminopimelic acid and menaquinone MK-7 was the major respiratory quinone. Analysis of the 16S rRNA gene shows the strains to cluster with species of the genera Thermoleophilum, Patulibacter, Conexibacter and Solirubrobacter to which they have pairwise sequence similarity in the range 87–88%. Based on 16S rRNA gene sequence analysis, physiological and biochemical characteristics we describe a new species of a novel genus represented by strain F2-233T (=CECT 7815T = LMG 26412T) for which we propose the name Gaiella occulta gen. nov., sp. nov. We also propose that this organism represents a novel family named Gaiellaceae fam. nov. of a novel order named Gaiellales ord. nov.