Pleomorphochaeta naphthae sp. nov., a new anaerobic fermentative bacterium isolated from an oil field

International audience; A novel anaerobic fermentative bacterium, strain SEBR 4209T, was isolated from a water sample of a Congolese oil field. Strain SEBR 4209T is phylogenetically related to the genus Pleomorphochaeta , in the family Spirochaetaceae . Its closest relatives are Pleomorphochaeta caudata SEBR 4223T (94.5 % 16S rRNA gene sequence similarity) and Pleomorphochaeta multiformis MO-SPC2T (94.3 % similarity). Like the other members of this genus, cells have a pleomorphic morphology, in particular an annular shape and long stalks. Optimal growth was observed at 37 °C, at pH between 6.8 and 7.0, and with 40 g l−1 NaCl. This strain was only able to grow by fermentation of carbohydrates. The fermentation products from glucose utilization were acetate, ethanol, CO2 and H2. Predominant fatty acids were C14 : 0, C14 : 0 DMA, C16 : 0 and C16 : 1ω7c. The major polar lipids were phosphoglycolipids, phospholipids and glycolipids. The G+C content of the DNA was 29.6 mol%. Based on phenotypic characteristics and phylogenetic traits, strain SEBR 4209T is considered to represent a novel species of the genus Pleomorphochaeta , for which the name Pleomorphochaeta naphthae sp. nov. is proposed. The type strain is SEBR 4209T (=DSM 104684T=JCM 31871T).