Difference between revisions of "Team:TMMU China"

Establishment of bacterial or eukaryotic chassis for plugging-in and plugging-out genetic circuits and new-to-nature functionalities is the foundational work for synthetic biology. Lactic acid bacteria (LAB) are a group of generally recognized as safe bacteria and can be optimized to be the next generation of Synthetic biology chassis, especially in the food industry and therapeutics. Lactococcus lactis is the most widely used LAB chassis in Synthetic biology. However, the device introduced by plasmid is unstable and the antibiotic resistant genes are forbidden to be used in food and therapeutics. The currently used genome integration system is also time-consuming and labor intensive.

Here, we established a visual selection system by insertion of a PnisZ promoter controlled lacZ gene into the His locus of L. Lactis strain NZ9000 chromosome. The constructed strain forms blue colony in the agar plate containing X-gal and nisin inducer. To clone the device of interest, lacZ gene was replaced by the device of interest and the recombinant strains forms white colonies.To improve L. lactis to be a better chassis, we also optimized the nisin expression system which can tolerate a higher nisin concentration, built a protein surface display system, and demonstrated that L. Lactis can be applied to pathogenic bacteria capsule engineering.