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Isolation, characterization and strain selection of a Paenibacillus species for use as a probiotic to aid in ruminal methane mitigation, nitrate/nitrite detoxification and food safety

Elizabeth A. Latham, William E. Pinchak, Julian Trachsel, Heather K. Allen, Todd R. Callaway, David J. Nisbet, Robin C. Anderson
Bioresource technology 2018 v.263 pp. 358-364
Campylobacter jejuni, Escherichia coli O157, Paenibacillus, coculture, denitrifying bacteria, fermentation, food safety, in vitro studies, methane, methane production, nitrates, nitrites, nitrogen, probiotics, rumen fluids, rumen microorganisms
The effects of dietary nitrate and Paenibacillus 79R4 (79R4), a denitrifying bacterium, when co-administered as a probiotic, on methane emissions, nitrate and nitrite-metabolizing capacity and fermentation characteristics were studied in vitro. Mixed populations of rumen microbes inoculated with 79R4 metabolized all levels of nitrite studied after 24 h in vitro incubation. Results from in vitro simulations resulted in up to 2 log₁₀ colony forming unit reductions in E. coli O157:H7 and Campylobacter jejuni when these were co-cultured with 79R4. Nitrogen gas was the predominant final product of nitrite reduction by 79R4. When tested with nitrate-treated incubations of rumen microbes, 79R4 inoculation (provided to achieve 10⁶ cells/mL rumen fluid volume) complemented the ruminal methane-decreasing potential of nitrate (P < 0.05) while concurrently increasing fermentation efficiency and enhancing ruminal nitrate and nitrite-metabolizing activity (P < 0.05) compared to untreated and nitrate only-treated incubations.