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Animal Sciences and Industry

Animal Sciences and Industry

Kansas State University
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Manhattan, KS 66506-8028


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Yeast protein sources

Dried fermentation biomass

Dried fermentation biomass consists of residual material from the feed-grade amino acid production. Feed-grade amino acids are derived from amino acid-producing bacterium in a process that requires a carbon source (sugars, typically from corn) and a nitrogen source (yeast extract) for bacterial fermentation. The fermentation biomass left after extraction of crystalline amino acids is used to produce dried fermentation biomass.

Dried fermentation biomass contains high concentration of crude protein (around 80%), lysine, and essential amino acids (Sulabo et al., 2013; Almeida et al., 2014). Standardized ileal digestibility of lysine and most amino acids is high, above 90% (Sulabo et al., 2013; Almeida et al., 2014).

The amino acid-producing bacteria within the dried fermentation biomass are not harmful to pigs, but a structural component of Gram-negative bacteria (lipopolysaccharide) may have endotoxin activity (Wallace et al., 2016), which affects feed intake.