Understanding concerning natural microbially mediated processes has been severely retarded by the common requirement to study microorganisms only as pure monocultures under aseptic conditions, in spite of the fact that, in virtually all real environments, microbial strains function in concert. This is particularly true in processes involving multiple elemental cycles and system segregation, as is the case for methanotrophic bacterial consortia functioning in nature. Although such consortia have exhibited a clear and important role in both natural and engineered aquatic systems, methanotrophic bacteria were largely excluded from detailed physiological study until the prospects for microbially derived animal feed and human food protein or single cell protein (SCP) production became a commercial objective in the 1960s and 1970s. This resulted in a wealth of both physiological and bioprocess information concerning methanotrophic consortia, which was, until recently, largely ignored as far as natural environmental processes were concerned. However, as concern about greenhouse gas, particularly methane and nitrous oxide emissions, from non-point aquatic sources increased, previously accumulated information from the development of commercial SCP production has become invaluable both in understanding factors affecting emission patterns and in the development of technology for emissions control. In the present commentary, the potential of mobile unconstrained membrane methanotrophic biofilm reactors for dissolved methane oxidation and possible dissolved nitrous oxide reduction to dinitrogen is introduced. (C) 2010 Elsevier B.V. All rights reserved.