MBIO 3280 Lecture Notes - Lecture 29: Short-Chain Fatty Acid, Neocallimastigomycota, Syntrophy
27 Nov 2017
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Document Summary
Plant macrostructure and cellulose fibers are broken down by mechanical action in the mouth and in rumen. Products are then degraded by fermentation in anoxic environment of rumen. Cellulolytic bacteria and protozoa hydrolyze cellulose to glucose. Glucose is fermented to volatile fatty acids and carbon dioxide, and some is converted to methane. Lipids are hydrolyzed, glycerol is fermented and fatty acids are hydrogenated. Fatty acids (acetate) pass through the rumen wall as main source of energy for animal (not glucose) Microbes also synthesize amino acids and vitamins that are essential for animal. Environment supports rich and diverse community: 1010 1011 bacterial per ml, 104 106 anaerobic protozoa per ml, 104 106 anaerobic fungi per ml. Microbes themselves, when regurgitated with cud, are also a major source of nutrition for the animal, (carbon and nitrogen source) (many die on exposure to o2) Cellulose degradation is a multi-step, multi-microbe process.
