Our new publication on sustainable fertilizer production has just been published in Sustainable Chemistry & Engineering.
Currently, urea is the most commonly used nitrogen fertilizer, but it has some issues:
- Most urea is derived from fossil carbon and uses fossil energy for its production,
- Urea is not directly taken up by plants, instead it is converted to ammonia and nitrate by bacteria. Plants can use ammonia and nitrate, but a lot of the nitrogen in the fertilizer is lost in this process (including washing into ground and surface water),
- Ammonia production also changes the pH of the soil, so farmers need to limit the amount of urea added or add additional soil conditioners to compensate.
Citrulline is a nitrogen-dense compound that can be directly taken up by plants, and is possible that it would be easier to manage than urea with respect to soil pH, nitrogen loss and nitrate run-off. It's also a very effective nitrogen fertilizer (see picture).
In a collaboration with Prof. Chris Easton's lab at the ANU and CSIRO Agriculture and Food, we have developed a novel method for making citrulline via a biotechnological route, using atmospheric CO2.
This work was co-funded by Australia's Grains Research and Development Corporation.