Abstract: To obtain high purity nisin product through simple process with low cost, nisin was precipitated from fermentation broth concentrated with organic solvents dichloromethane and n-butanol. Under 1:1 (V/V) conditions with butanol employed, the nisin purity was 63.32%, and the precipitation yield was 24.3%. While the purity and yield for dichloromethane was 39.96% and 36.04%, respectively. When a mixture of dichloromethane and butanol at a volume ratio of 1:1 was used, the nisin purity and the precipitation yield was 45.94% and 59.3%, respectively. This new method overcame many disadvantages of the existing method, such as low purity and high salt content. So it shows great potential for industrial applications.

Key words: precipitation, organic solvent, nisin, fermentation broth concentrate, separation