Taxonomy is the branch of science that classifies and names organisms. Lactobacillus were first described in 1901 with Lactobacillus delbrueckii, a species indispensable in yogurt, and grew exponentially since the beginning of the 21stcentury thanks to new genetic sequencing methods, to 261 species in March 2020. Many scientific genetic analyses ran in the past few years have shown that the huge heterogeneity this has led to makes it no longer reasonable to group all these 261 species under the genus Lactobacillus (Zhenget al., 2015, Salvetti et al., 2018, Parks et al., 2018). For this reason, the International Journal of Systematic and Evolutionary Microbiology (IJSEM) has released Wednesday 15 April 2020 a new classification scattering the species of the Lactobacillaceaefamily under Lactobacillus,Paralactobacillus, Pediococcus and 23 novel genera (Zheng et al., 2020), based on several genetic approaches and markers (average nucleotide identity, average aminoacid identity, core-gene aminoacid identity, core genome phylogeny, signature genes and metabolic or ecologic criteria), summarizing a titanic work to tidy up what has been referred to as a “huge pile of dirty dishes” by one of the authors.
While reclassifications have happened before, this is the first time it has such a dramatic reach and impact into the global market of food and food supplements – the probiotic supplement market is expected to reach nearly 70 billion USD value by 2023 according to Markets and Markets, and is largely composed of former Lactobacilli.
The objective is to create new genera with a better homogeneity that respects homogeneity rules between organisms – the International code of nomenclature of Prokaryotes includes 65 rules designated to assess the correctness of a microbial name! (Parker et al., 2015), is stable in the long term, and provides room for the accommodation of future species.