David Bergmann's recent research he has investigated the biochemistry and molecular biology of the oxidation of methane and ammonia by the methanotrophic bacteria, such as Methylococcus capsulatus Bath and the chemolithotrophic bacteria, such as Nitrosomonas europaea. He has been interested primarily in an enzyme, cytochrome P460, which catalyzes the oxidation of hydroxylamine (a metabolic intermediate in the pathway for ammonia oxidation) to nitrite. With undergraduates at BHSU, he is currently developing systems to over-express this enzyme in bacteria and perform site-directed mutagenesis on it to gain insights into its structure, catalytic properties, and possible evolution. Bergmann is interested in microbial ecology, especially concerning microbial transformations of nitrogen and methane in the environment. Also, he is studying the succession of heterotrophic bacteria on the gills of rainbow trout using a combination of traditional and molecular techniques.