Team:MIT

Biogurt: A Sustainable and Savory Drug Delivery System

Streptococcus mutans, the main cause of dental caries, binds to glycoproteins on the teeth. A clinical study (Kelly CG et al.; Nature Biotechnol. 1999) isolated the 20aa functional segment (p1025) that S.mutans uses to attach to the teeth. p1025 competitively inhibits the binding of S.mutans, causing unharmful bacteria to grow in its place, preventing the recolonization of S.mutans for 90 days.

We are engineering Lactobacillus bulgaricus, a bacteria commonly found in yogurt, to produce and secrete this peptide under a promoter activated by lactose.

The peptide p1025 could simply be added to any food. But production of this peptide by L. bulgaricus is an independent process, so inserting the gene into live bacteria in yogurt will enable continuous production. Since a new batch of yogurt can be made using the bacteria from a small amount of the old batch, a continuous supply of teeth-cleaning yogurt will be available from the first successfully engineered batch. This could be the key to providing effective dental health care in underdeveloped rural communities, especially if yogurt is already an integral part of the diet.

Also, the p1025 gene could be replaced by any other gene, so this same expression system could be used to produce other useful peptides. Yogurt with modified bacteria will provide a cheap, efficient, and delicious way to distribute vitamins, vaccines and more.

Results

Characterization

New Methods

• s.mutans Binding Assay
• p1025 Competitive Binding Assay