Preparation method of nisin aqueous solution with high clarity and high potency

The invention discloses a preparation method of a nisin aqueous solution with high clarity and high potency. The preparation method comprises the following steps: (1), taking nisin powder of which the potency is larger than 35000 IU/mg, and adding into distilled water to prepare an aqueous solution of which the potency is 50000 IU/mg; (2), carrying out ultrafiltration treatment on the aqueous solution through a 2000 D ultrafiltration membrane, so as to obtain a clear aqueous solution; (3), filtering the clear aqueous solution through 0.2 mu m microporous filtering membrane after sterilizing for 10 min under the temperature of 80 DEG C, so as to obtain the nisin aqueous solution. The nisin aqueous solution is prepared by taking high-purity nisin as a raw material, filtering through the ultrafiltration membrane, desalting and condensing by a reverse osmose membrane, the potency of the nisin aqueous solution is higher than 1000000 IU/mL, can be placed for one year without turbidity, and can be widely used in preservation of beverages, healthcare products, green products and the like.