Development of therapeutic or prophylactic recombinant Lactococcus lactis NZ9000-fermented milk with KRAS mimotope

ABSTRACT Milk is a common carrier for live cultures due to its abundant nutrients. Accumulating evidence has shown the efficacy of live culture as a vector to deliver drugs. This study aimed to develop recombinant Lactococcus lactis NZ9000-fermented milk expressing KRAS-139A-TTD mimotope. The fermentation conditions were optimized with inoculum concentration (6.4, 7, 8 log10 CFU/mL), temperature (22–25, 30, 37°C), and time (3, 16, 24, 48 h). The optimized L. lactis-fermented milk (8 log10 CFU/mL inoculum, 48 h, and 30°C) had a viability of 9.79 log10 CFU/mL, pH 5.16, and 0.54% titratable acidity. There was an absence of post-acidification and syneresis, with a 17.3% viability reduction after 26 days of storage at 4°C. Furthermore, the KRAS peptides expression in fermented milk after 10 days of storage was detected through SDS-PAGE. This showed that L. lactis NZ9000-fermented milk has the potential as KRAS positive therapeutic or prophylactic functional drink.