Method for extracting lactic acid in Nisin fermentation waste liquid by using weakly basic anion exchange resin

The invention provides a method for extracting lactic acid in a Nisin fermentation waste liquid by using weakly basic anion exchange resin, and belongs to the field of biochemical engineering. The method comprises the following steps: decoloring the Nisin fermentation waste liquid, deproteinizing, processing weakly basic anion exchange resin, carrying out content determination, adsorbing lactic acid by using the weakly basic anion exchange resin, desorbing, recovering, and concentrating. The method has the advantages of few operating steps, small impurity content, simplicity, feasibility, repeated use of the resin, low cost, and high efficiency, and the lactic acid extraction rate is about 70%; and the method allows lactic acid to be produced and the COD value of wastewater to be reduced, so the method reduces damages of environmental pollution to mankind.