Application of buffering strategy on Nisin fermentation by Lactococcus lactis

The character of Nisin fermentation process by Lactococcus lactis Z801 was studied and the buffering strategy was used to improve the fermentation condition,at last the titer of batch fermentation for Nisin was increased largely.The results showed that the titer was increased almost 2700IU/mL by using CM fermentation medium which prepared by Tris buffer solution,added CaCO3 1.5% and at the fermentation condition of pH 7.5,30℃,shake cultivation.We also found that adding CaCO3 could delay the fast decreasing of titer during later stage of fermentation process.