Fermentable energy

In fermentation, energy is obtained by shuffling organic molecules so that NADH produced in one step is oxidized by a subsequent product or products, which are reduced and excreted. Due to the small amount of energy obtained, only microbes can rely on fermentation as their sole energy source. More complex organisms utilize respiration alone or in combination with sunlight. 

The relationships used in predicting microbial protein from fermentable energy have high standard errors of estimate and should be used with caution. In addition, such relationships may be used to calculate yields of microbial protein only when the supply of energy is limiting. When the supply of protein to the microorganisms is limiting, this will determine the yield of microbial protein. 

Effect of feeding dairy cows diets with different fermentable energy on milk cheese-making features... 

In conclusion our results confinn that high fermentable diets, if well balanced, do not alter digestive functions and animal health. Moreover they shghtly affect milk fat and protein contents furthermore, neither the milk acidification rate (although low), nor the renneting properties (always optimal) were modified by the different content of fermentable energy of the diets used in this trial. 

Daniell, J., Kopke, M., Simpson, S.D. (2012) Commercial biomass syngas fermentation. Energies, 5,5372-5417. 

---