TECHNOLOGY FOCUS - BIOLOGY - Preparation (Claimed): The extraction of the sphingobacteria DX-T3-03 strain, comprises: (i) inoculating a soil suspension (5 wt.%) of mineral soil into an inorganic salt culture medium, cultivating for two months in a gradient pressure manner; (ii) allowing the cultivated strain to stand, diluting the upper aqueous layer in a gradient manner, inoculating the strain liquids with different diluting concentrations into a solid culture medium to enrich and cultivate, inoculating the pure single strain to a slant culture medium. Preferred Components: The inorganic salt culture medium in step (i) comprises (in g): ammonium sulfate (10), potassium dihydrogen phosphate (7.5), disodium hydrogen phosphate (10), ferric chloride (0.0125), magnesium sulfate heptahydrate (0.015), and distilled water (1000 ml) of pH 6.5-7. The gradient dilution in step (ii) is 10-1-10-10 gradient dilution. Preferred Method: The gradient pressure cultivation in step (i) comprises: adding filtered bacterial phenol with a gradient concentration and filtered bacteria zinc solution into the inorganic salt culture medium to increase the molar concentration of the phenol and zinc ions in the culture medium, where the concentrations of phenol is 300, 400, 500, 600, 700, 800, 900, 1000 mg/l, the concentration of zinc ions is 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4 mM/l, and the concentration changing interval is 4-7 days at 30-35 degrees C; vibrating at 150 rotations per minute and culturing. The preparation of the solid culture medium in step (ii) comprises: adding agar (1.5 wt.%) into a rich liquid culture medium at 10-5 Pa, disinfecting for 30 minutes, cooling to obtain the product, where the liquid culture medium comprises (in g) peptone (0.25), tryptone (0.25), yeast powder (0.5), glucose (0.5), magnesium sulfate heptahydrate (0.03) and distilled water (1000 ml) of pH 6.5-7. The step of enriching and culturing in step (ii) comprises: inoculating the bacterial liquid to an incubator at 30 degrees C to culture for 48 hours; selecting a single bacterial colony; lining at the solid culture medium; adding the culture dish into the incubator at 30 degrees C to culture for 48 hours, observing the shape of the bacterial colony, and repeating the steps 2-4 times to ensure the growth of the single strain.