PROBLEM TO BE SOLVED: To provide a novel microorganism or the like, capable of treating effluent containing nonionic surfactant highly efficiently.SOLUTION: There is provided a microorganism being an S45Y strain (NITE P-01636). The microorganism has excellent degradation ability of polyoxyethylene alkyl ether. There is also provided a method of treating effluent using the microorganism. According to the method of treating effluent of the present invention, polyoxyethylene alkyl ether can be biologically treated highly efficiently. For example, even in an environment where easily degradable general organic substances coexist, polyoxyethylene alkyl ether can be degraded efficiently. It is also possible to completely degrade polyoxyethylene alkyl ether.
