Team:Nanjing-China/Team

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The definition of nitrogen fixation

•What is nitrogen fixation?

Nitrogen → ammonia (NH3) or other molecules available to living organisms.

What is nitrogen fixation for?

-global food supply
-reduce the use of chemical nitrogen fertilizers 

Nitrogen fixation is essential for life.

The methods of nitrogem fixation

Nitrogen cycle

•Nitrogen fixation:
     —N2 → plants by bacteria
•Nitrification:
     —ammonium → nitrite → nitrate
     —Absorbed by plants
•Denitrification:
     —Release N to atmosphere

Haber-Bosch process

N2 + 3H2 → 2NH3(ΔH° = −91.8 kJ)
High temperature
High pressure
Need too much energy

Biological nitrogen fixation

Mild reaction conditions

Relatively inexpensive

High efficiency

Environmentally friendly

The choose of nitrogenase

Molybdenum
(MoFe)-dependent

Vanadium
(VFe)-dependent

Iron-only
(FeFe)-dependent

MoFe has been studied extensively

Nitrogen Fixation Gene Cluster

The minimal nif genes required for nitrogen fixation.

General principle of biological nitrogen fixation

01 Hydrolysis of ATP

Chemical energy (ATP)→Solar energy

03 MoFe protein forming complexes with low-potential donor
02 Electron transfer 04 Reduce N2 to NH3
01 Receive light signals 03 MoFe protein forming complexes with low-potential donor
02 Electron transfer 04 Reduce N2 to NH3

The characteristics of whole-cell

The property and advantage of whole-cells

•Fast proliferation to enable large-scale application
•Good portability to permit on-site monitoring
•Inexpensive and easy to preserve
• Intracellular cascade reactions to amplify signals
• Excellent specificity, sensitivity and stability