Community structure in a methanotroph biofilter as revealed by phospholipid fatty acid analysis

The microbial community structure of two biofilters used for the oxidation of methane and organic trace gases generated in landfills was analysed by phospholipid fatty acid composition. Community structure varied with biofilter depth, reflecting varying conditions of substrate supply as well as of organic carbon content, nutrient status and osmotic stress determined by the different materials used for the individual biofilter layers. Both biofilters were dominated by type II methanotrophs. In the biofilter charged with landfill gas containing significant amounts of trace organics, fatty acid 18:1ω7c constituted 87% of the methanotrophic PLFA, while the recognised signature fatty acids 16:1ω8 and 18:1ω8, which were well represented in the other biofilter, were entirely absent. This indicates the development of a highly specific methanotrophic population, presumably as a result of the adaption to continuous organic trace gas exposure.