Terriglobus albidus sp. nov., a member of the family Acidobacteriaceae isolated from Namibian semiarid savannah soil.

Abstract

A novel aerobic, chemo-organoheterotrophic bacterium, strain Ac_26_B10T, was isolated from a semiarid savannah soil collected in northern Namibia (Mashare, Kavango region). Based on analysis of its nearly full-length 16S rRNA gene sequence, the isolate belongs to the genus Terriglobus (family Acidobacteriaceae, order Acidobacteriales, class Acidobacteria) and shares 98.3 and 96.9 % 16S rRNA gene sequence similarity with its closest relatives, Terriglobus tenax DRP 35T and T. aquaticus O3SUJ4T. Cells were Gram-negative, coccoid to rod-shaped, non-motile and divided by binary fission. Strain Ac_26_B10T showed weak catalase activity and, in contrast to the other described species of the genus Terriglobus, was oxidase-positive. Compared with the already established species of the genus Terriglobus, the novel strain used a larger range of sugars and sugar alcohols for growth, lacked α-mannosidase activity and exhibited a higher temperature optimum of growth. DNA–DNA hybridization studies with its closest phylogenetic relative, T. tenax DSM 28898T, confirmed that strain Ac_26_B10T represents a distinct genomospecies. Its most abundant fatty acids were iso-C15 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. Dominant polar lipids were phosphatidylethanolamine and diphosphatidylglycerol. The predominant menaquinone was MK-8; minor amounts of MK-7 and MK-8(H2) were also recorded. The G+C content of the genomic DNA was 58.5 mol%. On the basis of our polyphasic analysis, Ac_26_B10T represents a novel species of the genus Terriglobus, for which the name Terriglobus albidus sp. nov. is proposed. The type strain is Ac_26_B10T ( = DSM 26559T = LMG 27984T).