There are billions of people who have dental caries around the world. Dental caries are related not only to the quality of life but also to health expectancy. The more aging society grows, the more dental health problems become important. Our project aims to develop new probiotics that continuously prevent dental caries with engineered Lactococcus lactis. We designed Lactococcus lactis which is able to bind specifically to biofilm and diffuse growth inhibitors against bacteria causing dental caries. We also considered the practical use of recombinant probiotics in the real world and suggest how we can use engineered bacteria safely outside of the laboratory. We hope that our project contributes to the world without dental caries.
In order to bind the biofilm formed by S. mutans, Glucan-binding protein C (GbpC) was selected. On the other hand, Cinnamaldehyde and Bacteriocin secreted from Lactiplantibacillus pentosus H99 were selected as the antibacterial compounds.
To confirm our recombinant Lactococcus lactis have the ability of antibacterial effect against Streptococcus mutans, we estimated the extent to which cinnamaldehyde diffuses when lactic acid bacteria synthesize it. We were able to determine the effective distance of lactic acid bacteria that actually exhibit antibacterial activity.
There are a variety of difficult issues to be addressed in order to develop recombinant probiotics. We discussed these issues from three perspectives: "Biosafety", "Interview", and "Education" for future realization.