A method for biotreating persistent organic waste water containing a higher fatty acid and a thickening polysaccharide without adding chemicals includes subjecting waste water to an oil-water separating process to separate it into aerobically treatable oil-containing waste water and anaerobically treatable polysaccharide-containing waste water. The anaerobically treatable polysaccharide-containing waste water is subjected to a reducing process in an anaerobic treatment to convert the polysaccharide in the waste water into a monosaccharide and to obtain monosaccharide water capable of aerobic treatment. The oil-containing waste water and the monosaccharide containing water are subjected to an aerobic bacteria treatment process to yield pretreatment water capable of aeration treatment. The pretreatment water is subjected to an aeration treatment process while controlling BOD density and is subjected to a solid-liquid separation by flocculating with activated sludge.

A method of converting waste into energy is provided. The method includes the following steps: (a) providing a lipid-containing substrate to react with a biocatalyst to produce a surfactant molecular liquid; (b) pretreating an organic waste with the surfactant molecular liquid to produce a first organic liquid; (c) subjecting the first organic liquid to an ultrasonic treatment to produce a second organic liquid; and (d) subjecting the second organic liquid to an anaerobic biological treatment for conversion to methane. The biocatalyst includes at least one lipase. Moreover, the surfactant molecular liquid includes at least one of monoglyceride and diglyceride. A waste treatment system for converting waste into energy is also provided.

In an aspect, the present disclosure provides a novel microorganism having an ester degrading ability. In an aspect, the present disclosure provides a combination of novel microorganisms having an oil degrading ability. In an embodiment, the microorganism of the present invention includes a yeast belonging to the genus Yarrowia. In an embodiment, the microorganism of the present invention includes Yarrowia lipolytica. In an embodiment, the present disclosure provides a combination of a Burkholderia bacterium with a Yarrowia yeast. In an embodiment, provided is an oil degrading agent that comprises the microorganism of the present disclosure.