USE OF METHANOTROPHIC BACTERIA IN GAS-PHASE BIOREACTORS TO ABATE METHANE IN COAL-MINE ATMOSPHERES

The potential of using the methanotrophic bacterium Methylomonas methanica to remove methane from coal mine atmospheres was investigated using a bench scale, gas phase bioreactor. The bioreactor was constructed from a cylindrical glass column packed with bio-rings to support bacterial growth. M. methanica grew readily on the bio-rings with a total of 133.4 g (wet weight) of the bacterium being contained in the bioreactor. Methane in air mixtures ranging from 0 to 50.9% were recirculated through the 4.5 1 (void volume) bioreactor at a rate of 200 ml min-1, and significant levels of methane removal were noted. With a 35% methane/air mixture, 90.4% of the methane was removed in 24 h. This equated to a removal rate of approximately 38 mg methane h-1. Using a 12% methane/air mixture the removal rate was approximately 23 mg methane h-1. From these results, it was concluded that methanotrophic bacteria grown in gas phase bioreactors are capable of removing significant amounts of methane from methane/air mixtures and may be of practical use in removing methane from coal mine atmospheres.