Method for dyeing polyester fiber fabric based on biologically-prepared nanometer pigment dye liquor

The invention relates to a method for dyeing a polyester fiber fabric based on biologically-prepared nanometer pigment dye liquor. The method comprises the steps that 1, high-yield serratia marcescens is utilized for producing the nanometer pigment dye liquor, wherein an improved fermentation medium is adopted, a nonionic surfactant system is added 0-48 h after inoculation, the culture temperature is 25-28 DEG C, the rotational speed of a shaker is 180-250 rpm, time is 50-100 h, light-avoiding culture is carried out, thalli are removed through centrifugation after fermentation is over, and the nanometer pigment dye liquor is obtained; 2, the dye liquor is utilized for dyeing the polyester fiber fabric, wherein a dyeing assisting system is added into the dye liquor, the pH is regulated to range from 4.0 to 8.0, the bath ratio is 1:(10-60), dyeing is carried out for 20-90 min at the temperature of 100-130 DEG C, and lastly soaping and washing are carried out. The nanometer pigment preparation method is simple,