Method for synthesizing benzene-containing polyhydroxyalkanoate by mixed fermentation of high-density microbes under nitrogen restriction

The invention discloses a method for synthesizing benzene-containing polyhydroxyalkanoate by mixed fermentation of high-density microbes under nitrogen restriction. The method comprises the following stages of: 1, adding less than or equal to 0.5g/L of benzene-containing organic substance and 5 to 20g/L of sugar serving as a carbon source into a fermentation medium, inoculating a seed solution oftwo or more microbes, judging the consumption of the carbon source by using online signals, and adding the carbon source to ensure the growth requirement of the microbes; and 2, regulating the pH value by using a nitrogen-containing alkali solution when the light absorption density of microbial cells is 30, and stopping supplying aqueous ammonia and other nitrogen-containing substances so that the nitrogen content of the fermentation solution is reduced to 0.001mol/L and the nitrogen restriction is realized; and monitoring the change of dissolved oxygen and the pH value, and thus obtaining the benzene-containing polyh