The invention belongs to the technical field of kitchen
waste treatment and particularly discloses a method for improving the yield of
biodiesel prepared through a kitchen
grease enzymic method through pretreatment. The method includes the following steps that firstly, impurities in kitchen waste are removed, and
microwave treatment, ultrasonic wave treatment and hydro-
thermal treatment is conducted on the kitchen waste in sequence; secondly, three-phase separation is conducted, and upper-layer
grease is obtained; thirdly, oxidation is conducted by leading
ozone in; fourthly, immobilized composite
lipase is added into
grease obtained in the third step, and short chain
alcohol is added for conducting a
transesterification reaction to prepare the
biodiesel, wherein the immobilized composite
lipase in the forth step comprises
geotrichum candidum
lipase, candida lipase and
burkholderia cepacia lipase. According to the method,
microwave treatment, ultrasonic wave treatment and hydro-
thermal treatment are combined for treating kitchen waste, the kitchen grease precipitated amount is increased by 10-50 % than that before treatment and is increased by 2-30% than that obtained by adopting single pretreatment, the kitchen grease precipitated amount is effectively increased, and the productivity and the yield of the
biodiesel prepared through the enzymic method are obviously improved.