Evolutionary Operation (EVOP) factorial design technique was sequentially used to optimize
concentrations of various media ingredient such as MRS broth, nisin and milk in order to
maximize nisin production using Lactococcus lactis (MTCC-440). Traditional method for
optimization of media ingredient involves changing one variable at a time and keeping all
other parameters constant. However, this method does not determine the interactive effects
of different factors. EVOP factorial designing technique was applied consecutively and the
results were analyzed statistically and next set of experiments were carried by getting the
clue from the previous set of experiments till the effect of individual media components are
less than the error limits. Streptococcus agalactiae (NCIM-2401) was used as an indicator
strain for quantification of nisin by agar diffusion assay. Nisin yield increased when
fermentation was carried out at 30°C at 100 rpm with final formulated media having mediaingredient
concentrations MRS broth, milk and nisin 5.5 %, 0.7 % and 0.25 5g/mL
respectively. Consequently, with successful implementation of EVOP factorial design
technique Nisin production was increased from 206.1 5g/mL to 271.69 5g/mL, which was
approximately 1.31 fold.