Modeling of Growth and Nisin Production by Lactococcus lactis During Batch Fermentation

Abstract

Nisin, the only FDA-approved bacteriocin widely used as a natural food preservative, is produced by lactic acid bacteria Lactococcus lactis subsp. lactis. Mathematical models of biomass and nisin production during fermentation not only provide information about the kinetic-metabolic nature of nisin, but also facilitate the control and optimization of nisin production. In this study, several models were tested and modified in order to describe biomass, nisin, and lactic acid production by L. lactis in suspended-cell batch culture. All models were designed so that they contained only biologically relevant parameters. The re-modified logistic and Gompertz models proposed in this study adequately described the growth, and validation showed that they could be used for accurate prediction of the parameters (slope = 1.01, R2 = 0.99). As for nisin production, the Luedeking-Piret model fit considerably well and could be successfully use to predict nisin production from the value of biomass (slope = 1.04, R2 = 0.98).