f Rubrobacter xylanophilus sp. nov., a New Thermophilic Species Isolated from a Thermally Polluted Effluent

One strain of a thermophilic, slightly halotolerant bacterium was isolated from a thermally polluted industrial runoff near Salisbury, United Kingdom. This organism, strain PRD-1T (T = type strain), for which we propose the name Rubrobacter xylanophilus sp. nov., produces short gram-positive rods and coccoid cells and forms pink colonies. The optimum growth temperature is approximately 60°C. Unusual internal branched-chain fatty acids (namely, 12-methylhexadecanoic acid and 14-methyloctadecanoic acid) make up the major acyl chains of the lipids. The results of our 16S rRNA sequence comparisons showed that strain PRD-1T is related to Rubrobacter radiotolerans and that these two organisms form a deep evolutionary line of descent within the gram-positive Bacteria.