Thauera sedimentorum sp. nov., Isolated from Coastal Sediment

Abstract

A Gram-negative, strictly aerobic, rod-shaped, non-spore-forming bacterium, designated CAU 1555^T, was isolated from a sediment sample collected on Jeju Island, Republic of Korea. Growth of the isolate was observed at 20-37 °C (optimum at 30 °C) and pH 5.5-10.0 (optimum at 8.0). Phylogenetic analysis based on the result of 16S rRNA gene sequences revealed that strain CAU 1555^T belonged to the genus Thauera and was closely related to Thauera hydrothermalis GD-2^T (98.4% sequence similarity), Thauera lacus D20^T (96.6%), and Thauera linaloolentis 47Lol^T (95.5%). Strain CAU 1555^T possessed phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid, and one aminophospholipid as the major polar lipids; Q-8 as the predominant respiratory quinone; and C_16:0, summed feature 3 (comprising C1_6:1ω6c and/or C_16:1ω7c), and summed feature 8 (comprising C_{18:1 ω7c}/ C_{18:1 ω6c}) as the major fatty acids. The average nucleotide identity (ANI), average amino acid identity (AAI), and digital DNA-DNA hybridization (dDDH) values between the new isolate and T. hydrothermalis GD-2^T were 84.5%, 86.4%, and 28.0%, respectively. Whole-genome sequencing of strain CAU 1555^T revealed 3,955,289 bp with a DNA G + C content of 68.0 mol%. Based on the results of its polyphasic properties and genomic analysis, the isolate represents a novel species within the genus Thauera, for which the name Thauera sedimentorum sp. nov. is proposed, with CAU 1555^T (= KCTC 72546^T = MCCC 1K04065^T) as the type strain.