[Studies on purification and some properties of nisin from Lactococcus lactis subsp. lactis Al2]

Nisin from Lactococcus lactis subsp. lactis AL2 was extracted with n-propanol from NaCl-saturated culture and purified by ion-exchange chromotography on CM-Sephadex C-25. Nisin was purified 1.63 fold with a yield of 41.7%. The molecular weight of nisin was determined by SDS-PAGE to be about 3500. Nisin activity was stable at low pH and sensitive to digestion by a-chymotrypsin. Nisin is capable of inhibiting a broad range of gram-positive bacteria. In contrast, the gram-negative bacteria, yeasts, molds and Nip+ L. lactis subsp. lactis ATCC11454 were not inhibited.