Unexpected environmental source of methane discovered

(University of Washington Health Sciences/UW Medicine) Roughly 10 percent of nitrogen-fixing microorganisms contain the genetic code for manufacturing a back-up enzyme, called iron iron-only nitrogenase, to do their job. New research reveals that this enzyme allows these microorganisms to convert nitrogen gas to ammonia and carbon dioxide into methane at the same time. This enzymatic pathway is a previously unknown route for the natural biological production of methane.