Over several decades, the genus Lactobacillus became unmanageable, encompassing 262 species. Rudimentary research tools lumped any newly-discovered bacteria into the genus, making the taxonomy “very screwed up.”
“The lactobacillus taxonomy became a stack of dirty dishes — everyone knew somebody should do it, anyone could have done it, but nobody did it,” says Michael Gänzle, PhD, professor and Canada Research Chair in Food Microbiology and Probiotics at the University of Alberta. He spoke at a TFA webinar The New Taxonomy of Lactobacillus. “It has become very obvious that the genus is too diverse to group all or the organisms into a single genus. …We need taxonomy to actually describe which group of organisms they mean because if you say lactobacillus in the old sense, we mean a group of organisms that is so diverse that using the same genus name doesn’t make too much sense.”
The lactobacillus genus is large, regulated in many countries and economically important. Gänzle is one of 15 scientists involved in a year-long project using sophisticated DNA tools to analyze the new taxonomy. Findings’ published in the April issue of the Journal of Systematic and Evolutionary Microbiology, spread the species over 26 genera, including 23 new (novel) ones.
“The new taxonomy of lactobacilli means taxonomists have to navigate 23 new names, but maybe I can convince you that renaming the taxonomy is also the best thing since the invention of sliced bread because it does facilitate the communication on all things which relate to lactobacilli,” Gänzle says. He referred to the completed taxonomy as the “lactobacillus monster” because it covers 77 pages.
Despite its heft, he’s proud of the completed project, which reclassifies the genus into relevant groups. “It makes it easier to identify cultures of food applications,” Gänzle says. The group of authors also developed an online tool that makes it easy to look up old names and new names, and provides reference to (genome) sequence data at lactobacillus.ualberta.ca or lactobacillus.uantwerpen.be.
Ben Wolfe, PhD, Associate Professor at Tufts University, moderated the webinar. Wolfe studies the ecology and evolution of microbiomes in his lab (and is a TFA Advisory Board member).“It’s really great to see this community coming around this very important problem,” Wolfe says. “This really helps clarify a lot of things for us.
For the average artisanal fermented food producer, not much will change with the new taxonomy. Producers of traditionally fermented foods don’t put the organisms in their food or drink on their labels — it’s the companies selling starter cultures.
“For someone who doesn’t buy and sell cultures, this doesn’t change,” Gänzle adds. “There will be a transition period until everyone is familiar with the names and putting them on the label. Most, if not all, can still be abbreviated with L.”