Evaluation of methane oxidation and the production potential of soils in an urban school

Methane oxidation and the production potentials of ground soil (soil A) and garden soil (soil B, C, & D) in an urban school were evaluated, and the methanotrophic and methanogen communities in the soil samples were quantified using quantitative realtime PCR. The methanotrophic community in the raw soil A sample possessed a 6.1 x10³ gene copy number/g dry weight soil, whereas those in the raw soils B∼D samples were 1.6-1.9 x 10⁵gene copy numbers/g dry weight soil. Serum bottles added with the soil samples were enriched with methane gas, and then evaluated for their methane oxidation potential. The soil A sample had a longer induction phase for methane oxidation than the other soils. However, soil A showed a similar methane oxidation potential with soils B&simD after the induction phase. The methanotrophic community in the enriched soil A sample was increased by up to 2.3 x 10 ⁷gene copy numbers/g dry weight soil, which had no significantly difference compared with those in soils B-D (1.2-2.8 x 10⁸ gene copy numbers/g dry weight soil). Methane production showed a similar tendency to methane oxidation. The methanogens community in raw soil A (1.7 x 10⁵ gene copy number/g dry weight soil) was much less than those in raw soils B∼D (1.3-3.4 x 10⁷ gene copy numbers/g dry weight soil). However, after methane gas was produced by adding starch to the soils, soil samples A∼D showed 10⁷ gene copy numbers/g dry weight soil in methanogens communities. The results indicate that methanotrophic and methanogenic bacteria have coexisted in this urban school's soils. Moreover, under appropriate conditions for methane oxidation and production, methanotrophic bacteria and methanogens are increased and they have the potential for methane oxidation and production.