Spent Craft Brewer's Yeast Reduces Production of Methane and Ammonia by Bovine Rumen Microbes

Methane and ammonia are byproducts of rumen fermentation that do not promote animal growth, and methane is a key contributor to anthropogenic climate disruption. Cows eructate every few breaths and typically emit 250–500 L of methane gas daily. Significant research is focused on finding diets and additives that lower the production of methane and ammonia. Emerging research has shown that humulones and lupulones, molecules that are found in the cones of hops (Humulus lupulus), have potential in this regard. These molecules, which are also key flavor components in beer, are biologically active: they are known inhibitors of Gram-positive bacteria. Ruminants' sophisticated digestive systems host billions of microorganisms, and these systems' outputs will likely be affected in the presence of brewer's yeast (Saccharomyces cerevisiae). So-called spent yeast is produced during the beer-brewing process and contains humulones and lupulones in concentrations that vary by beer style, but it is generally discarded as waste. Our research suggests that adding spent craft brewer's yeast to rumen microbes by single time-point 24-h in vitro incubations suppresses production of methane and ammonia. This project examines the correlation between the quantities of hop acids in spent yeast and the production of methane and ammonia by bovine rumen microbes in vitro. We determined, by HPLC, the hop acid concentrations in spent yeast obtained from six beer styles produced at a local brewery. We performed anaerobic incubation studies on bovine rumen microbes, comparing the effects of these materials to a baker's yeast control and to the industry-standard antibiotic monensin. Results include promising decreases in both methane (measured by GC–FID) and ammonia (measured by colorimetric assay) in the presence of craft brewer's yeast, and a strong correlation between the quantities of hop acids in the spent yeast and the reduction of methane and ammonia. Notably, two of the yeast samples inhibited methane production to a greater degree than the industry-standard antibiotic monensin. Our results suggest that spent brewer's yeast has potential to improve ruminant growth while reducing anthropogenic methane emission.

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Spent Brewer’s Yeast as a Source of Insoluble β-Glucans

International Journal of Molecular Sciences ◽

10.3390/ijms22020825 ◽

2021 ◽

Vol 22 (2) ◽

pp. 825

Author(s):

Ionut Avramia ◽

Sonia Amariei

Keyword(s):

Emulsion Stability ◽

Extraction Process ◽

Brewer’S Yeast ◽

Brewer's Yeast ◽

Brewing Process ◽

Food Applications ◽

Water Holding ◽

Potential Food ◽

Insight Into

In the brewing process, the consumption of resources and the amount of waste generated are high and due to a lot of organic compounds in waste-water, the capacity of natural regeneration of the environment is exceeded. Residual yeast, the second by-product of brewing is considered to have an important chemical composition. An approach with nutritional potential refers to the extraction of bioactive compounds from the yeast cell wall, such as β-glucans. Concerning the potential food applications with better textural characteristics, spent brewer’s yeast glucan has high emulsion stability and water-holding capacity fitting best as a fat replacer in different food matrices. Few studies demonstrate the importance and nutritional role of β-glucans from brewer’s yeast, and even less for spent brewer’s yeast, due to additional steps in the extraction process. This review focuses on describing the process of obtaining insoluble β-glucans (particulate) from spent brewer’s yeast and provides an insight into how a by-product from brewing can be converted to potential food applications.

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The utilization of non-protein nitrogen in the bovine rumen. 8. The nutritive value of the proteins of preparations of dried rumen bacteria, rumen protozoa and brewer's yeast for rats

Biochemical Journal ◽

10.1042/bj0560151 ◽

1954 ◽

Vol 56 (1) ◽

pp. 151-156 ◽

Cited By ~ 69

Author(s):

Mary L. McNaught ◽

E. C. Owen ◽

Kathleen M. Henry ◽

S. K. Kon

Keyword(s):

Nutritive Value ◽

Rumen Bacteria ◽

Brewer’S Yeast ◽

Protein Nitrogen ◽

Bovine Rumen ◽

Brewer's Yeast ◽

Rumen Protozoa

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Evaluation of an In Vitro Bioassay for the Detection of Purified Ricin and Castor Bean in Beverages and Liquid Food Matrices

Journal of Food Protection ◽

10.4315/0362-028x-70.10.2377 ◽

2007 ◽

Vol 70 (10) ◽

pp. 2377-2382 ◽

Cited By ~ 19

Author(s):

JENNIFER L. BRZEZINSKI ◽

DAVID L. CRAFT

Keyword(s):

Castor Bean ◽

Colorimetric Assay ◽

Cell Damage ◽

Jurkat Cells ◽

Biologically Active ◽

Detection Methods ◽

Mouse Bioassay ◽

Animal Testing ◽

Vitro Assay

The potential use of ricin as a biological weapon in food highlights the necessity for the development of food-specific detection methods. Current methods for the detection of ricin consist of various immunoassays, which detect only one subunit of the ricin toxin and therefore may not be indicative of a biologically active molecule. An in vivo assay, such as a mouse bioassay, can indicate the biological activity of the toxin; however, this method is not feasible for laboratories that do not have animal testing facilities. The purpose of this study was to develop an in vitro assay for the detection of biologically active ricin in beverages and liquid foods. Acidic and high-protein beverages were spiked with either purified ricin or ground castor beans and added to cultured human Jurkat cells. After an overnight incubation, the supernatant was tested for lactate dehydrogenase (LDH) activity with a colorimetric assay. LDH was released from the cytosol upon cell damage and was positively correlated with cell death. Ricin was detectable in all the matrices tested, with a sensitivity of 10 to 100 pg/ml. Biologically active ricin was detectable in all the matrices incubated with ground castor bean material. This method provides a confirmatory way to detect biologically active ricin that can be utilized by laboratories lacking animal facilities.

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THE ACTION OF SULFONAMIDES ON THE RESPIRATION OF BACTERIA AND YEAST

The Journal of General Physiology ◽

10.1085/jgp.25.6.805 ◽

1942 ◽

Vol 25 (6) ◽

pp. 805-817 ◽

Cited By ~ 8

Author(s):

M. G. Sevag ◽

M. Shelburne ◽

Stuart Mudd

Keyword(s):

Structural Similarity ◽

Inhibitory Effect ◽

Brewer’S Yeast ◽

Respiratory Enzymes ◽

Staph Aureus ◽

E Coli ◽

Brewer's Yeast ◽

Inhibiting Effect

The inhibiting effects of sulfonamide drugs and their derivatives on the anaerobic decarboxylation of pyruvic acid by Staphylococcus aureus, Escherichia coli, baker's and brewer's yeast, and a carboxylase preparation from brewer's yeast have been investigated. These drugs are: sulfanilamide, sulfapyridine, sulfadiazine, sulfamethyldiazine, sulfathiazole, sulfamethylthiazole, sulfanilamido-5-ethyl-4-thiazolone, 2-aminopyrimidine, 2-aminothiazole, and 2-aminopyridine. The sulfathiazole ring appears to exercise decidedly greater specific inhibiting effect on the carboxylases of Staph. aureus and E. coli. The inhibiting effect on yeast carboxylase is non-differentiable among all the substances tried, except sulfamethyldiazine which is completely ineffective on the carboxylases of the organisms studied. The specific inhibitory effect of sulfathiazole on the carboxylases of Staph. aureus and E. coli in comparison to sulfanilamide, sulfapyridine, and sulfadiazine is in harmony with in vivo and in vitro experimental results of other investigators. The results of the present investigation appear to support the hypothesis (1) that sulfonamides exert their bacteriostatic action through chemical affinity for the carrier proteins of certain respiratory enzymes of the bacterial cell, and that this affinity may in part be related to structural similarity between components of the drugs and the corresponding respiratory coenzymes.

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A fraction derived from brewer's yeast inhibits cholesterol synthesis by rat liver preparations in vitro

British Journal Of Nutrition ◽

10.1079/bjn19910087 ◽

1991 ◽

Vol 65 (2) ◽

pp. 285-299 ◽

Cited By ~ 9

Author(s):

E. S. Holdsworth ◽

D. V. Kaufman ◽

E. Neville

Keyword(s):

Rat Liver ◽

Plasma Lipids ◽

Normal Diet ◽

Water Soluble ◽

Sterol Synthesis ◽

Brewer’S Yeast ◽

Nicotinamide Riboside ◽

Brewer's Yeast

Brewer's yeast was grown on a defined medium containing tracer51Cr with or without added chromium. The two batches of yeast contained 10 μg/g (high-Cr) or 80 ng/g (low-Cr). Extracts were prepared and fractionated. A third batch of yeast (third batch) was grown with added Cr, and fractionated. Rats were reared on either rat cubes (normal diet) or on a low-Cr diet (low-Cr), or on rat cubes with added cholestyramine (cholestyramine diet). Preparations of rat liver, both cell-free and intact hepatocytes, incorporated acetate-carbon into fatty acids and cholesterol. These processes were inhibited by a yeast fraction containing small, neutral, water-soluble compounds. The degree of inhibition was the same whether the liver came from normal rats or rats fed on the low-Cr diet. Similarly the inhibitory effect was found with identical amounts of extracts from low- or high-Cr yeasts. Therefore, Cr compounds do not appear to account for the inhibitory effects of brewer's yeast. Use of other substrates indicated that the site of inhibition of sterol synthesis was apparently between acetyl-CoA and mevalonate. One inhibitory substance was isolated from yeast and was found to be nicotinamide riboside. This may have been produced from NAD(P) during the preparation of yeast extracts, and it may be produced from dietary yeast supplements during digestion in vivo. Nicotinamide riboside may be partly responsible for the reported effects of yeast supplements on plasma lipids in humans.

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