NOVELTY - A microorganism belonging to Ensifer or Pseudomonas genus and capable of utilizing nonionic surface-active compound (1) on aerobic conditions, is new.    USE - For treatment and purification of wastewater containing nonionic surface-active agent such as alkylphenol polyethoxylate (claimed), and degrading the metabolites of the agent such as alkylphenol and short chain alkylphenol polyethoxylate, where the metabolites are endocrine disrupters.    ADVANTAGE - The microorganism enables effective aerobic degradation of the metabolite of nonionic surface-active agent, and treatment of wastewater containing the agent. Ability of the microorganisms to effectively degrade nonyl phenol polyethoxylate was tested as follows. Shaking culture of Ensifer sp. AS08 was carried out for 7-8 days at 28degreesC in the optimal culture medium containing 0.1% nonyl-phenol polyethoxylate. After culture, microbial cells were centrifuged, collected and suspended in buffer and was washed with 50 mM Tris hydrochloric acid buffer. Then, 50 ppm of nonyl phenol ethyl ether or nonyl phenol hydroxy ethoxyethyl ether was added, and shaking reaction was performed at 28degreesC. Microbial cells were removed by centrifugation after three days. The reaction liquid was concentrated under reduced pressure, and was extracted at pH 7.0 and 2.0 using dichloromethane. The neutral fraction was analyzed by high performance liquid chromatography (HPLC), and the acidic fraction was analyzed by gas chromatography-mass spectrometry (GC-MS) analysis. The results showed that 75% of nonyl phenol hydroxy ethoxyethyl ether and 80% or more of nonyl phenol ethyl ether was degraded in three days.    DETAILED DESCRIPTION - A microorganism belonging to Ensifer or Pseudomonas genus, and capable of utilizing nonionic surface-active compound of formula (1) on aerobic conditions.    R=4-24C alkyl group;and    n=0 or natural number, preferably 0, 1 or 2.    INDEPENDENT CLAIMS are included for the following:    (1) method for culturing the above microorganism using the culture medium containing the compound of formula (1); and    (2) method for wastewater treatment, involves degrading compound of formula (1) on aerobic conditions using the microorganisms.