FERMENTATION CONTROLLED FOR INCREASING NISIN BIOSYNTHESIS IN LACTOCOCCUS LACTIS

Abstract

The control of fermentation is considered the way by that it influences strongly onmicrobial growth and biosynthesis. There are papers published on batch fermentation selectionfor nisin production. L.lactic 145 is recently found that it could use sucrose as carbon sourceand metabolizes sharply in the exponential phase. That result the pH changes to acid range inbetween 4.5 after 12 h cultivation. The nutrition depletion and pH in acid is known influence negatively on nisin synthesis. That's why the establishment of fermentation model in which pHis regulated and sucrose is added is the way by that nisin biosynthesis in L.lactic 145 being improved. The fermentation was set up to run at regime of pH controlled at 6.5 and sucrose was added 40 g/l as final concentration. By that way of fed-batch fermentation the activity of nisin biosynthesis of L.laclis 145 increased very highly, nearly two folds than normal one