Difference between revisions of "Team:Nanjing-China/Demonstrate"

Overview

This year, we found an economic, efficient and environmental-friendly way to utilize nitrogen in the air. Our design consists of three parts: biosynthesis of CdS semiconductor, light-driven nitrogen fixation and reaction device. All three parts have gone through in-depth examination and successfully work out under real conditions.
The following list exhibits our key achievements in this project.
Constructed and tested engineered E. coli which express nitrogenase and OmpA-PbrR.
Constructed and tested light-driven system based on OmpA-PbrR protein.
Achieved light-driven nitrogen fixation.
Designed a reaction device that cater for our light-driven nitrogen fixation reaction.

Biosynthesis of CdS semiconductor

One key element of light-driven system in our design is CdS semiconductor precipitated by the OmpA-PbrR fused protein. We used TEM-EDX analysis to characterize CdS semiconductor precipitated on E. coli cell. We also determined the maximum concentration of Cd2+ appropriate for strain growth, as well as the amount of CdS that can be precipitated on cell surface.

Light-driven nitrogen fixation

CdS semiconductor generate excited electrons under illumination which are then passed to nitrogenase for nitrogen fixation. We introduce nitrogenase to E.coli to enable it to reduce dinitrogen to ammonia. We conducted QPCR to detect relative transcriptional level of each nif gene. We also plan to optimize the structure of nif gene operon after modeling. Using acetylene reduce assay, we then verify the activity of nitrogenase in our system.

Reaction device

We designed a light-driven microbe reaction device to apply our system to practical use. After a few test, we proved our device to be quite practical. (see device for more details)