Australian Centre for Water
and Environmental Biotechnology

Project Dates: 2009


Methane is a potent greenhouse gas with a global warming potential 25 times that of carbon dioxide on a 100-year horizon. The discovery of nitrite/nitrate-dependent anerobic methane oxidation (n-DAMO) process, in which methane is oxidized anaerobically to provide electrons for denitrification, forms an important link between global carbon and nitrogen cycles and fundamentally changes our understanding of the methane cycle. It not only stimulates the appreciation of the ecological significance of n-DAMO microorganisms, but also opens novel avenues to develop more sustainable wastewater treatment processes. High-level nitrogen removal cannot be achieved through the conventional Anammox process, as part (20%) of the nitrite is converted into nitrate. Nitrate reduction by n-DAMO archaea using methane as an electron donor provides a novel possibility of achieving complete nitrogen removal through cooperation of Anammox and DAMO archaea. On the other hand, the involvement of n-DAMO bacteria will entail the system with robustness against influent dynamics. In such a process, nitrite is converted into dinitrogen by n-DAMO bacteria and by Anammox bacteria with nitrate as a by-product; methane is used by n-DAMO archaea to denitrify nitrate into nitrite, which is subsequently removed by Anammox and n-DAMO bacteria.