X-SEED® KAT Advanced for increased biomass and enzyme production

Formulating an appropriate culture medium is essential to achieve optimal performance in fermentation processes, including the production of microbial biomass and recombinant enzymes.

This work presents the effects of replacing a standard yeast extract with one containing high amounts of free amino acids and small peptides, such as X-SEED® KAT Advanced. Impact on microbial biomass was investigated by measuring viable cell counts of Escherichia coli and Streptococcus thermophilus cultures.

For enzyme production assessments, E. coli expressing Green Fluorescent Protein (GFP) was utilised; both biomass and GFP production were measured in real time. 

Key observations

  • E. coli and S. thermophilus biomass production was highly influenced by the yeast extract used in the culture medium.
  • Use of yeast extract with high amounts of free amino acids improved viable cell counts and growth rates of S. thermophilus by 52% and 15% respectively.  
  • Similarly, final biomass and growth rate of E. coli cultures also increased by 10% and 15% respectively. 
  • GFP-expressing E. coli cultures grown in presence of X-SEED® KAT Advanced began GFP production earlier and showed a 37% increase in final enzyme titres. 
  • Overall, this study demonstrates that delivering high levels of free amino acids and short-chain peptides can significantly improve both growth performance and enzyme production in a strain-specific manner.

Biomass and fluorescence of GFP-expressing E.coli when grown in two different yeast extracts*

*Experiments were performed in biological triplicates in Biolector Pro.  Average values are shown and had standard deviation of less than 5%.

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