Influence of nutrients on oxidation of low level methane by mixed methanotrophic consortia

Abstract

Low-level methane emissions from coal mine ventilation air (CMV-CH4; i.e., 1 % CH4) can significantly contribute to global climate change, and therefore, treatment is important to reduce impacts. To investigate CMV-CH4 abatement potential, five different mixed methanotrohic consortia (MMCs) were established from soil/sediment sources, i.e., landfill top cover soil, bio-solid compost, vegetated humus soil, estuarine and marine sediments. Enrichment conditions for MMCs were as follows: nitrate mineral salt (NMS) medium, pH ~ 6.8; 25 °C; 20-25 % CH4; agitation 200 rpm; and culture period 20 days, in mini-bench-top bioreactors. The enriched cultures were supplemented with extra carbon (methanol 0.5-1.5 %, formate 5-15 mM, and acetate 5-15 mM), nitrogen (nitrate 0.5-1.5 g L(-1), ammonium 0.1-0.5 g L(-1), or urea: 0.1-0.5 g L(-1)), and trace elements (copper 1-5 μM, iron 1-5 μM, and zinc 1-5 μM) in different batch experiments to improve low-level CH4 abatement. Average CH4 oxidation capacities (MOCs) of MMCs varied between 1.712 ± 0.032 and 1.963 ± 0.057 mg g(-1)DWbiomass h(-1). Addition of formate improved the MOCs of MMCs, but the dose-response varied for different MMCs. Acetate, nitrate and copper had no significant effect on MOCs, while addition of methanol, ammonium, urea, iron and zinc impacted negatively. Overall, MMCs enriched from marine sediments and landfill top cover soil showed high MOCs which were largely resilient to nutrient supplementation, suggesting a strong potential for biofilter development for industrial low-level CH4 abatement, such as those present in CMV.

Characterization of the Bacterial Community Associated with Methane and Odor in a Pilot-Scale Landfill Biocover under Moderately Thermophilic Conditions

“…Environmental factors such as temperature, precipitation, moisture content, organic matter content, and pH affect biocover performance [ 10 , 11 , 27 - 32 ]. Fig.…”

Controlling mechanism of coal chemical structure on biological gas production characteristics

“…The coal‐forming process will disrupt some of the bonds and aromatic ring structures that are connected to the coal structure, forming some intermediates such as acids, phenols, alcohols, and ketones under the microbial metabolism and dehydrogenase, carboxylase, and synthase action. Oxygen atoms will be introduced into the coal structure in this process, resulting oxygen content increase . The carbon content will decrease with continuous production of methane and the consumption and dissolution of organic carbon in coal .…”

“…Oxygen atoms will be introduced into the coal structure in this process, resulting oxygen content increase. 35,36 The carbon content will decrease with continuous production of methane and the consumption and dissolution of organic carbon in coal. 37 However, the change in the carbon and oxygen content after the secondary gas production is exactly opposite to that of the primary degradation.…”

Biofiltration of methane from cow barns: Effects of climatic conditions and packing bed media acclimatization

“…It is assumed herein that reductions in CH4 concentrations are the result of biotic oxidation processes. We did not perform microbiological tests that would confirm the presence of -or an increase in -active methanotrophic consortia, such as documented by Gebert et al (2003), Humer and Lechner (1999) and Karthikeyan et al (2017Karthikeyan et al ( , 2016.…”