Probiotics industry prepares for changes to Lactobacillus genus

Nomenclature has been challenging despite the prominence of the group due to the high level of phenotypic and genotypic diversity

Lactobacillus is one of the most well-known genera used in probiotics. As one of the most economically important groups, any change is significant, and big ones are on the horizon.

The genus Lactobacillus includes over 200 species that are widely used in fermented food preservation and biotechnology or that are explored for beneficial effects on health.

Despite the well-researched effects of Lactobacillus, the nomenclature has been challenging due to the high level of phenotypic and genotypic diversity that they display and because of the uncertain degree of relatedness between them and associated genera.

A study in 2018 investigated the feasibility of dividing the genus into more homogeneous genera/clusters, exploiting genome-based data. The paper deduced the relatedness of 269 species belonging primarily to the families Lactobacillaceae and Leuconostocaceae.

The results found that both distance-based and sequence-based metrics showed that Lactobacillus was paraphyletic and revealed the presence of 10 methodologically consistent subclades.

From these results, Dr Elisa Salvetti, the lead author who works for Microbion, presented two ways to reclassify lactobacilli:

  • A conservative division into two subgeneric groups based on the presence/absence of a key carbohydrate utilisation gene.
  • A more radical subdivision into 10 groups that satisfy more stringent criteria for genomic relatedness, characterised by uniform patterns of the presence/absence of specific sets of genes.

The more radical option may offer potential as a discovery tool for understanding differential biological features within the genus.

Another outcome from reclassification/subdivision into more uniform taxonomic nuclei is accurate molecular markers for regulatory approval applications.

New structure

Since the study, the reclassification of the taxonomy has gone from a proposal to a reality.

The current Lactobacillus genus will be split into at least 10, and perhaps as many as 23, genera.

No species names will change, but many species (including commercially important ones) will have different genus names.

Industry reaction

Although a certain level of disruption is expected, but the probiotic field may benefit from embracing these changes and developing strategies to minimise any difficulties resulting from them.

Nutra-Ingredients reported on the Probiota event in Copenhagen. At this event, Dr Elinor McCartney took to the stage with Salvetti, and said: “Every threat is an opportunity, and this is a wonderful marketing opportunity.

"If you look at the marketing and labelling of probiotics at the moment, the names of the specific species are written in very small letters while the brand names and logos get preference. ​But any changes to names open the opportunity to talk about your particular strain in a legal and good sense," ​Salvetti asserted.

Reclassification will facilitate scientific communication related to lactobacilli and hopefully prevent misidentification issues, which are still the major cause of mislabelling of probiotic and food products reported worldwide.

This is the positive take on this coming change. On the cautious side, companies are concerned about patents with the old nomenclature.

Another speaker at the Probiota event, Dr Bruno Por, said that the people responsible for changing the names of the strains are professionals and ‘they should be aware of links between patents and strains’. So in his opinion, there should be no issues.