Reduction in Methane Emissions From Acidified Dairy Slurry Is Related to Inhibition of Methanosarcina Species

Habtewold, Jemaneh; Sokolov, Vera; VanderZaag, Andrew; Wagner‐Riddle, Claudia; Dunfield, Kari E.

doi:10.3389/fmicb.2018.02806

Cited by 38 publications

(34 citation statements)

References 55 publications

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“…The pattern of CH 4 production in the acidified tanks suggests that there was CH 4 production occurring, but at much lower rates than in the control tanks. In fact, Habtewold et al (2018) found that the methanogen abundance was reduced by 6% and the activity by 20% in the same acidified manure. They suggest that acidification inhibits, rather than kills, the methanogens present in manure (Habtewold et al, 2018).…”

Section: Resultsmentioning

confidence: 97%

Greenhouse Gas Mitigation through Dairy Manure Acidification

et al. 2019

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Liquid dairy manure storages are sources of methane (CH4), nitrous oxide (N2O), and ammonia (NH3) emissions. Both CH4 and N2O are greenhouse gases (GHGs), whereas NH3 is an indirect source of N2O emissions. Manure acidification is a strategy used to reduce NH3 emissions from swine manure; however, limited research has expanded this strategy to reducing CH4 and N2O emissions by acidifying dairy manure. This study compared control dairy manure (pH 7.4) with two treatments of acidified manure using 70% sulfuric acid (H2SO4). These included a medium pH treatment (pH 6.5, 1.4 mL acid L−1 manure) and a low pH treatment (pH 6, 2.4 mL acid L−1 manure). Emissions were measured using replicated mesoscale manure tanks (6.6 m2) enclosed by large steady state chambers. Both CH4 and N2O were continuously measured (June–December 2017) using tunable diode laser trace gas analyzers. Ammonia emissions were measured three times weekly for 24 h using acid traps. On a CO2 equivalent basis, the medium pH treatment reduced total GHG emissions by 85%, whereas the low pH treatment reduced emissions by 88%, relative to untreated (control) manure. Total CH4 emissions were reduced by 87 and 89% from medium and low pH tanks, respectively. Ammonia emissions were reduced by 41 and 53% from medium and low pH tanks, respectively. Additional research is necessary to make acidification an accessible option for farmers by optimizing acid dosage. More research is need to describe the manure buffering capacity and emission reductions and ultimately find the best approaches for treating farm‐scale liquid dairy manure tanks. Core Ideas Acidification reduced total CO2–eq GHGs from liquid dairy manure by 85 to 88%. Total CH4 emissions were reduced by 87 to 89% from acidified manure. NH3 emissions were reduced by 41 to 53% from acidified manure. A range of yearly H2SO4 cost was estimated to be Can$6.55 to $19.6 cow−1.

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Section: Resultsmentioning

confidence: 97%

Greenhouse Gas Mitigation through Dairy Manure Acidification

et al. 2019

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“…However, it has been shown previously that e-SOX produces acidity even down to 4 cm 12 . Low pH values impede fermentation processes and methanogenesis, resulting in the reduction of methane emissions 21,22 . For example, a pH shift from pH 6.9 to 6.8 has been reported to decrease CH 4 production in flooded rice soil by 26% 23 .…”

Section: Discussionmentioning

confidence: 99%

Cable bacteria reduce methane emissions from rice-vegetated soils

2020

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Methane is the second most important greenhouse gas after carbon dioxide and approximately 11% of the global anthropogenic methane emissions originate from rice fields. Sulfate amendment is a mitigation strategy to reduce methane emissions from rice fields because sulfate reducers and methanogens compete for the same substrates. Cable bacteria are filamentous bacteria known to increase sulfate levels via electrogenic sulfide oxidation. Here we show that one-time inoculation of rice-vegetated soil pots with cable bacteria increases the sulfate inventory 5-fold, which leads to the reduction of methane emissions by 93%, compared to control pots lacking cable bacteria. Promoting cable bacteria in rice fields by enrichment or sensible management may thus become a strategy to reduce anthropogenic methane emissions.

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“…Real-time qPCR was performed using an Applied Biosystems StepOnePlus real-time PCR system using clear 96-well PCR plates (Bio-Rad Laboratories, Inc., Hercules, CA). The total and active fraction of the methanogen populations were quantified by targeting methyl coenzyme A reductase (mcrA) genes and transcripts, respectively, using mlas-mod F and mcrA-rev-mod R primers (Habtewold et al, 2018). The total and active fraction of the methanogen populations were quantified by targeting methyl coenzyme A reductase (mcrA) genes and transcripts, respectively, using mlas-mod F and mcrA-rev-modR primers (Habtewold et al, 2018).…”

Section: Nucleic Acid Extraction and Quantitative Real-time Pcrmentioning

confidence: 99%

“…Kavanagh et al (2019) reported 96% reductions of CH 4 and 85% of NH 3 with H 2 SO 4 acidification (to pH of 5.5). The mechanism of CH 4 reduction is still unclear, as H 2 SO 4 and pH reduction can disrupt microbial communities throughout all the processes of organic matter degradation as well as methanogens directly (Habtewold et al, 2018). Habtewold et al (2018) reported a methanogen reduction of 6% in abundance and 20% in activity between untreated and acidified dairy manure but observed no difference in the microbial communities.…”

Section: Introductionmentioning

confidence: 99%

“…The mechanism of CH 4 reduction is still unclear, as H 2 SO 4 and pH reduction can disrupt microbial communities throughout all the processes of organic matter degradation as well as methanogens directly (Habtewold et al, 2018). Habtewold et al (2018) reported a methanogen reduction of 6% in abundance and 20% in activity between untreated and acidified dairy manure but observed no difference in the microbial communities. This suggests that H 2 SO 4 primarily disrupts methanogenesis rather than other microbial processes, however, more research is necessary to confirm these results.…”

Section: Introductionmentioning

confidence: 99%

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Acidification of Residual Manure in Liquid Dairy Manure Storages and Its Effect on Greenhouse Gas Emissions

Sokolov

VanderZaag

Habtewold

et al. 2020

Front. Sustain. Food Syst.

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Liquid manure storages are an important source of greenhouse gases (GHG) on dairy farms. Methane (CH 4) and nitrous oxide (N 2 O) are the predominant GHGs, while ammonia (NH 3) is an indirect source of N 2 O. Addition of acid to manure has shown promising emission reductions, however, cost of acidification may be unfeasible for farmers. Fully cleaning storages has also shown to reduce CH 4 , due to removal of inoculating effects of residual manure ("inoculum") on fresh manure (FM). However, complete removal of inoculum is practically impossible on large farms, thus acidifying only the inoculum may reduce GHGs without requiring acidification of all FM. This study aimed to quantify the effect of acidified inoculum on CH 4 , N 2 O, and NH 3 emissions from stored manure and quantify the changes in methanogen abundance and activity. Emissions were measured from six 10.6 m 3 storages filled with 20% inoculum (1-year-old manure) and 80% FM. Inoculum was treated in three ways: untreated (control); previously acidified (1-year prior); and newly acidified with 70% H 2 SO 4 (1.1 L m −3 manure). The CH 4 and N 2 O emissions were continuously measured from June-November using tunable diode trace gas analyzers coupled with venturi air flow systems. The NH 3 emissions were measured at 24-h intervals 3 × weekly using acid traps. The activity and abundance of methanogens were quantified by targeting the Methyl Coenzyme M Reductase A (mcrA) gene and transcript which encodes a subunit of the key enzyme that catalyzes the final step of methanogenesis. Bacterial abundance was quantified by targeting the bacterial 16S rRNA gene. Quantifications were performed using quantitative real-time PCR. CH 4 emissions were reduced by 77% using newly acidified inoculum and 38% using previously acidified inoculum, compared to the control with untreated inoculum (36.1 g CH 4 m −2). Significant treatment reductions in mcrA gene and transcript abundance suggest that CH 4 reductions were caused by disruption of methanogen activity. NH 3 and N 2 O emissions were reduced by 33 and 73% using acidified inoculum and 23 and 50% using previously acidified inoculum, respectively, compared to the control. Results suggest that lower acid rates and acidifying less frequently may still have good treatment effects while minimizing cost.

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Reduction in Methane Emissions From Acidified Dairy Slurry Is Related to Inhibition of Methanosarcina Species

Cited by 38 publications

References 55 publications

Greenhouse Gas Mitigation through Dairy Manure Acidification

Greenhouse Gas Mitigation through Dairy Manure Acidification

Cable bacteria reduce methane emissions from rice-vegetated soils

Acidification of Residual Manure in Liquid Dairy Manure Storages and Its Effect on Greenhouse Gas Emissions

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