Isolation and identification of a thermophilic aerobic denitrifier and its denitrification characteristics

A thermophilic aerobic denitrifier strain named XF3 was isolated from the sequencing batch reactor activated sludge of a sewage treatment plant in Taiyuan city. According to the physiological biochemical identification and the 16S rDNA gene analysis,the strain XF3 was generally identified as Brevibacillus borstelensis. Single factor experiments were used to investigate the influence of carbon source,C /N,pH and inoculum size on its growth and denitrification characteristics. The results indicated that the optimum conditions were obtained as follows; sodium succinate as carbon source,C /N ratio of 12 ∶ 1,pH value of 7,inoculum size of 10%( volume fraction). It was also shown that the strain had a good capability of heterotrophic nitrification: the ammonia nitrogen concentration was reduced from 73 mg /L almost to zero within 48 hours.