Screening of a Novel Bacterium That Degrades LAS and Removes Nitrogen

A large increase in nitrogen in domestic sewage causes a series of environmental problems and the eutrophication of water bodies. The linear alkylbenzene sulfonate (LAS) is a type of anionic surfactant. As a widely used detergent, LAS is a toxic pollutant in domestic sewage. A novel gram-negative bacterium, designated as type strain A-1 T, was isolated from septic tanks in Ankang, Shaanxi Province, China. Cells of strain A-1 T were aerobic, motile, and rod-shaped. The DNA G + C content was 63.4 mol%. It contained Q8 (57.24%) and Q9 (42.76%) as the respiratory quinones and summed feature 8 (C18:1ω7c or C18:1ω6c), summed feature 3 (C16:1ω7c or C16:1ω6c), and C16:0 as the major fatty acids. The major polar lipids of the strain were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, and PE. Whole-genome sequencing of the strain was performed. The strain A-1 can strongly degrade LAS and nitrogen. At initial total nitrogen concentration less than 50 mg/L, the nitrogen removal rate reached more than 90%, and the accumulation of nitrate and nitrite was small. At initial LAS concentration less than 100 mg/L, the removal rate of LAS was higher than 80%. When the strain was added to the treatment of artificial wetland sewage, the removal effect of LAS and nitrogen after adding the strain was significantly better than that before adding the strain. The treated sewage can meet the Class A standard of the discharge standard of pollutants for municipal wastewater treatment plant (GB 18,918–2002).