Insights into the production of erythritol by strains of <i>Limosilactobacillus fermentum</i> of sourdough origin

Lactic acid bacteria have a limited biosynthesis capacity. Their main carbohydrate breakdown pathways enable them to produce energy and to maintain their redox balance. The latter is accomplished through the production of lactic acid in the case of homofermentative lactic acid bacteria and ethanol or acetic acid in the case of heterofermentative ones. However, under certain conditions, other branches of this pathway become active, which lead to end-metabolites that are produced seldomly. An example of such an end-metabolite is erythritol, which was already detected during sourdough production but never investigated in detail. The present study showed the production of erythritol by <i>Limosilactobacillus fermentum</i> inhabiting sourdough environments and its involvement in redox balancing.