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ARS Home » Midwest Area » Lexington, Kentucky » Forage-animal Production Research » Research » Publications at this Location » Publication #315855
Title: Hop acid-rich spent craft brewer's yeast modulates gut bacterial growth

Author
item BRYANT, ROBERT - Asheville Flavor Innovations Llc
item COHEN, SETH - Appalachian State University
item Flythe, Michael
item HARLOW, BRITTANY - University Of Kentucky
item O'CONNELL, SEAN - Western Carolina University
item TRUITT, REBECCA - Warren Wilson College
item MARTIN, LANGDON - Warren Wilson College

Submitted to: Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/9/2015
Publication Date: 4/7/2015
Citation: Bryant, R.W., Cohen, S., Flythe, M.D., Harlow, B.E., O'Connell, S.P., Truitt, R.J., Martin, L.J. 2015. Hop acid-rich spent craft brewer's yeast modulates gut bacterial growth. Meeting Proceedings. Pg. 2.

Interpretive Summary:

Technical Abstract: Alpha and beta hop acids (humulones and lupulones) from Humulus lupulus are inhibitors of Gram-positive organisms and important natural antibiotics for beer fermentation and carbohydrate feed stocks for biofuel production. Recent observations (Bryant and Cohen) of high levels of hop acids in spent yeast from craft beer brewing suggested studies to evaluate the antibiotic properties of hop acid rich craft brewers yeast regarding their influence on gut bacteria. Pasteurized spent yeast from craft beer brewing caused zones of inhibition on agar lawns of Gram-positive Bacillus cereus and Clostridium sticklandii SR. Hop-free baker’s yeast was inactive. Biochromatography by TLC demonstrated that the majority of the antibiotic activity in craft brewer’s yeast resided in hop acids. Craft yeast inhibited ammonia production 60% in mixed ruminant anaerobic bacterial cell suspensions and reduced numbers of hyper ammonia producing bacteria by 10 fold versus baker’s yeast. Additional studies with craft yeast are in progress looking at its effect on the anaerobic gut metabolites methane and short chain fatty acids. The gut microbiome influences GI health, immune response and brain function. Modulators of the microbiome are seen as new ways to influence health and hop acid-rich craft brewer’s yeast could play a role in gut health.