<!DOCTYPE html>

Demonstrate

Functional validation of GSH module and SAM module by HPLC

To further validate the GSH module and SAM module, we tested the GSH and SAM content in final engineered strain L. lactis/pNZ-GMcA.

It is known that L. lactis NZ9000 cannot form GSH and can form little SAM by itself. As shown in Figure.1, no GSH was detected in L. lactis NZ9000 as expected. And GSH was obviously appeared during the fermentation, illustrating that GSH module was effective. And Figure.2 showed that more SAM were accumulated in strain L. lactis/pNZ-GMcA than wild-type, illustrating the good function of SAM module.

Figure. 1 HPLC analysis of GSH samples

Figure. 2 HPLC analysis of SAM samples

Functional validation of adhesion factor module by self-aggregation value assay

To validate adhesion factor module, we carried out self-aggregation assay which could reflect the adhesivity of strains. As shown in Figure. 3, by introducing plasmid pNZ-GMcA, L. lactis could have obviously improvement in self-aggregation value, illustrating that adhesion module was expressed successfully and worked well.

Figure. 3 Comparison of self-aggregation value between L.lactis NZ9000 and L. lactis/pNZ-GMcA

Functional comparison among different composite modules

After constructing plasmids containing different combination of the three modules, they were introduced to L. lactis NZ9000 by electroporation, separately. Then, the function of these engineered strains were validated by detected the GSH and SAM content and self-aggregation value.

Figure. 4 Functional comparison among different composite modules in L. lactis.

Process demonstrate of smart yogurts with three target modules

After validation of the function of the final engineered strain L. lactis/pNZ-GMcA, we applied it to produce smart yogurts. As depicted below, we produced three kinds of smart yogurts. One was produced by using wild-type strain L.lactis NZ9000 adding GSH and SAM in the process. Another one was produced by using engineered L. lactis/pNZ-GMcA and the last one using wild-type strain L.bulgaricus and engineered L. lactis/pNZ-GMcA without adding GSH and SAM.

Figure. 5 Schematic diagram of producing smart yogurts

The content of GSH and SAM in the smart yogurts

The GSH and SAM content of the smart yogurts in the fermentation at 6 and 12 hours were detected. As shown in Figure. 6, the smart yogurt made by using engineered L. lactis contained obvious more GSH and SAM. The content increased with the increase of cell numbers.

Figure. 6 GSH and SAM content in the smart yogurts at 6 and 12 hours. Asterisk represented not detected.

Application of patent for the production of smart yogurts

At last, we have applied a Chinese patent for producing smart yogurts using the engineered strain containing three modules. And it was registered by National Patent Office of China.

Figure. 7 The patent application for producing smart yogurts