Influence of pH drop on both nisin and pediocin production by Lactococcus lactis and Pediococcus acidilactici

Aims: To develop a kinetic model for describing the specific effect of pH drop on nisin and pediocin production in whey. Methods and Results: The effect of pH drop on both bacteriocin productions was tested in non-buffered whey and whey buffered at initial pH 6.3 with 0.03, 0.10 and 0.25 mol l(-1) of potassium hydrogen phthalate-NaOH. An accurate description of the experimental data of nisin and pediocin obtained at different pH drops is obtained with the proposed model. Conclusions: The proposed model was able to typify both bacteriocins as pH-dependent primary metabolites. Significance and Impact of the Study: The decisive role of pH drop for bacteriocin production on whey was demonstrated and modelled. This study contributes to a better understanding of underlying metabolic regulatory mechanisms, which could facilitate the optimization of bacteriocin production for upscaling.