Location: Soil, Water & Air Resources ResearchTitle: Microbial assemblages and methanogenesis pathways impact methane production and foaming in manure deep-pit storages
|YANG, FAN - Iowa State University|
|ANDERSEN, DANIEL - Iowa State University|
|KENT, ANGELA - University Of Illinois|
|PEPPLE, LAURA - Puck Custom Enterprises, Inc|
|GATES, RICHARD - Iowa State University|
|HOWE, ADINA - Iowa State University|
Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2021
Publication Date: 8/3/2021
Citation: Yang, F., Andersen, D.S., Trabue, S.L., Kent, A.D., Pepple, L.M., Gates, R.S., Howe, A.S. 2021. Microbial assemblages and methanogenesis pathways impact methane production and foaming in manure deep-pit storages. PLoS ONE. 16(8). https://doi.org/10.1371/journal.pone.0254730.
Interpretive Summary: Foam accumulation in swine manure deep-pits has been linked to explosions and flash fires that are safety concerns for both animals and humans. This study monitored over a 13 month period changes in the physical and chemical composition of manure, rates of methane gas production in manure, swine feed information, and the microbial composition of manure. All this information was analyzed for correlations and associations. The results showed that increased methane gas production was correlated to higher foaming rates, less digestible feed ingredients, and changes in the microbial community favoring efficient use of excess nutrients. Information in this report will be of value for growers, engineers, and scientist working on foaming issues associated with waste processing.
Technical Abstract: Foam accumulation in swine manure deep-pits has been linked to explosions and flash fires that pose devastating threats to humans and livestock. It is clear that methane accumulation within these pits is the fuel for the fire; it is not understood what microbial drivers cause the accumulation and stabilization of methane. Here, we conducted a 13-month field study to survey the physical, chemical, and biological changes of pit-manure across 46 farms in Iowa. Our results showed that an increased methane production rate was associated with less digestible feed ingredients, suggesting that diet influences the storage pit’s microbiome. Targeted sequencing of the bacterial 16S rRNA and archaeal mcrA genes was used to identify microbial communities’ role and influence. We found that microbial communities in foaming and non-foaming manure were significantly different, and that the bacterial communities of foaming manure were more stable than those of non-foaming manure. Foaming manure methanogen communities were enriched with uncharacterized methanogens whose presence strongly correlated with high methane production rates. We also observed strong correlations between feed ration, manure characteristics, and the relative abundance of specific taxa, suggesting that manure foaming is linked to microbial community assemblage driven by efficient free long-chain fatty acid degradation by hydrogenotrophic methanogenesis.