Method for extraction purification of polymer gamma-polyglutamic acid (gamma-PGA) from fermentation broth

The invention discloses a method for extraction purification of polymer gamma-polyglutamic acid (gamma-PGA) from fermentation broth and belongs to the technical field of chemistry. The method comprises the following steps of 1, removing bacteria in the fermentation broth, 2, carrying out decoloring by active carbon, 3, orderly removing anions and cations in the fermentation broth, 4, concentrating the fermentation broth and 5, carrying out drying. The method is an economic and feasible pretreatment technology, effectively realizes bacterium-liquid separation of gamma-PGA high-viscosity broth and removal of impurities such as pigment in the gamma-PGA high-viscosity broth, and carries out ultrafiltration freeze-drying and then refining thereby producing the high-purity gamma-PGA finished product. The method provides a feasible technical route for final commercialization of gamma-PGA.