Preparation method of surface active agent

The invention discloses a preparation method of a surface active agent. The method adopts arthrobacterium as a strain. The method includes the following two methods: (1) performing metabolic regulation for arthrobacterium under the optimal culture condition to prepare a trehalose lipids compound; (2) preparing the trehalose lipids compound by using arthrobacterium resting cells, wherein the culture temperature is 25 to 38 DEG C, the pH is 4.5 to 7.8, and air or oxygen-rich air is charged into a culture substance base on 0.6-1.4 (volume ratio) per minute, and after fermenting, extracting the fermenting liquid through 1.5 to 3.0 times methanol-chloroform solvents or ethyl acetate, wherein methanol to chloroform is 1: 1.8-2.8 (V/V). With the adoption of the metabolic regulation method, the output of trehalose lipids surface active agent is up to about 25g per liter; the conversion rate of a carbon source matrix is increased by twice; the method for producing the surface active substance through the resting cells is a low-cost and simple method for preparing the surface active agent.