The invention relates generally to a system and method the treatment of substrate-variable gaseous emissions comprising dynamic concentrations of organic materials comprising methane and one or more non-methane organic compounds that can be metabolized by methane-oxidizing microorganisms, and in one specific embodiment, to a system and method for the treatment of substrate-variable methane emissions through the use of methanotrophic microorganisms in a species-universal polymer production process. Certain embodiments of the invention are particularly advantageous because they reduce environmentally-destructive methane emissions and produce harvestable end-products.