Insights into the use of different peptide size fractions by Bifidobacteria

Bifidobacteria have emerged as one of the most important group of intestinal organisms with regards to human health, and therefore have strong prominence in the market as probiotics. However, the process of growing Bifidobacteria in industrial settings has many challenges, as it is not always easy to achieve the optimal conditions for growth.

Selecting the right nitrogen source for the growth medium is one of these challenges. Previous studies have shown that Bifidobacteria require amino acids and peptides to grow, however, the exact need can depend strongly on the particular strain used. This review investigates why different sizes of peptides are optimal for the growth of different Bifidobacteria. The review also discusses an analytical method that can be used to better understand and review which protein source works best for your target Bifidobacteria.

Main observations

  • Most Bifidobacteria species are not able to utilize whole protein fractions, since they lack proteinases. As most strains have shown to have peptidase activity, it can be beneficial to supply the complex media with protein hydrolysates with high fractions of small peptides.
  • The difference in peptide preference between strains could depend on the different membrane transport systems for peptides, being specific for particular sizes, whereas transporters for free amino acids might even not exist at all.
  • Size exclusion chromatography is one technique which can be used to understand and select the right complex nutrient from the wide ranges of peptone products offered, including those derived from yeast.

SEC-results of various peptone products from different sources. X-Seed® Peptone is a hydrolysate originating from yeast. The results provide an indication of the peptide sizes of protein hydrolysates: one amino acid has an average weight of approximately 110 Da.

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