The lactobacillus, also called Döderlein's bacillus is a genus of facultative aerobic bacteria. There are several species such as Lactobacillus acidophillus and Lactobacillus reuteri.
I have several questions, all linked, for the concern of speciation of bacteria species used for lactic fermentation by humans.
- Are all species that are used for cheese and yoghurt fermentation part of the genus Lactobacillus?
- Do all species used for cheese and yoghurt fermentation form a monophyletic clade?
- Did the speciation of this clade occurr before or after the use of these bacteria by humans?
- What was the ecological niche of the ancestor(s) before humans used them for cheese and yoghurt?