Eubacterium coprostanoligenes and Methanoculleus identified as potential producers of metabolites that contribute to swine manure foaming

Authors: STROM, NOAH - University Of Minnesota; MA, YIWEI - University Of Minnesota; ANDERSEN, DANIEL - Iowa State University; Trabue, Steven - Steve; CHEN, CHI - University Of Minnesota; HU, BO - University Of Minnesota

Submitted to: Journal of Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/22/2021
Publication Date: 4/1/2022
Citation: Strom, N., Ma, Y., Andersen, D., Trabue, S.L., Chen, C., Hu, B. 2022. Eubacterium coprostanoligenes and Methanoculleus identified as potential producers of metabolites that contribute to swine manure foaming. Journal of Applied Microbiology. 132(4):2906-2924. https://doi.org/10.1111/jam.15384.
DOI: https://doi.org/10.1111/jam.15384

Interpretive Summary: Manure foaming is a major problem in swine farms with deep pits in the Upper Midwest. Foaming can cause damage to property, livestock, and people. The causes of manure foaming remain unknown. A survey of foaming and non-foaming barns was conducted at 10 farms in Iowa and Illinois. We identified chemical markers that differed between foaming and non-foaming manure. Microbial communities also differed between foaming and non-foaming barns. Foaming barns had higher levels of larger fatty acids and proteins, compounds which are associated with foam. Non-foaming manures had higher concentrations of smaller fatty acids compounds that are known to slow formation of methane gas. We identified several bacteria that differed in relative abundance in foaming versus non-foaming pits. Bacteria associated with foaming manure produced material that stabilize foam. These results suggest an explanation for manure foaming in which growth of certain microorganisms leads to excessive production of methane gas and stabilizing proteins. Roles of other factors in manure foaming, such as animal feed are discussed in the reports. Information in this report will be of value for growers, engineers, and scientists working on foaming issues associated with waste processing.

Technical Abstract: Swine manure foaming causes significant damage to property, livestock, and people. We collected 53 foaming and non-foaming swine manure samples from farms in Iowa and Illinois, used targeted and 54 untargeted metabolomics analyses to identify chemical markers, and performed microbial community 55 and metagenomics analyses on a subset of samples. Swine manure foam had significantly higher levels of 56 total bile acids, total long chain fatty acids (LCFA) than other manure layers. Untargeted metabolomics 57 showed that foam layer samples had significantly higher levels of ubiquinone 9 and ubiquinone 10. 58 Alanine, isoleucine/leucine, diacylglycerols ((DG(13:0/20:5) and DG(14:1/18:4)), 59 phosphtatidylethanolamines (PE(13:0/14:1) and PE(14:0/14:1)), and vitamin K2 were increased in 60 foaming samples, while ceramide (Cer(18:0/15:0)) was significantly increased in non-foaming samples. Sixty-one OTUs classified as Eubacterium coprostanoligenes and Methanoculleus were more abundant in foaming 62 samples, and E. coprostanoligenes was significantly correlated with levels of diacylglycerols. 63 Metagenomics analyses revealed that genes involved in diacylglycerol biosynthesis were overrepresented 64 in foaming samples, as were genes involved in the biosynthesis of branched chain hydrophobic amino 65 acids. These results suggest a hypothetical mechanism for manure foaming in which proliferation of 66 Methanoculleus leads to excessive production of methane, while production of diacylglycerols and 67 hydrophobic proteins E. coprostanoligenes and other microbes facilitates bubble formation and 68 stabilization.