The experiments we have done during this year can be separated into four main steps: The first step was the cloning and the confirmation of the E. coli strains for the G. algens dextranase's expression (BBa_K3493000). Secondly, we have optimized the proteic expression of our dextranase by testing multiple conditions and thus purified the protein. Thirdly, we realized micro-SNT enzymatic assays with the previously purified dextranase to characterize its main properties as pH and temperature for optimal activity. Finally, rheological assays allowed us to quantify the activity of our dextranase in ropy syrup, an essential test for the proof of concept for this project. As a part of our contribution to a registry part, experiments were also performed for the S. mutans dextranase (BBa_K2551003).

In summary, we were able to express and purify our dextranase from G. algens using E. coli BL21. We used the synthetic gene inserted in a conventional pET28a vector for protein expression followed by IMAC chromatography. The purified enzyme was characterized using micro-SNT enzymatic assays that revealed, in the condition of ropy maple syrup (pH 6.5 and temperature between 15 and 20 °C), that the dextranase would be adapted for the treatment. It was also confirmed using rheological assays.


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