ConclusionBread waste flour is a good substrate for the growth of lactic acid bacteria and Bifidobacterium present in the two starters. The combina-tion of starter BY and enzymatic and non-enzymatic treatments with salt proved to be the best option for the fermentation of a bread waste-based beverage according to the growth kinetics parameter. The enzymatic treatment resulted in a pH reduction, an increased total acidity, and a desirable decrease in the WHC of the fermented beverages. Moreover, the enzymes addition caused a higher production of glucose and iso-maltose, whereas maltose decreased due to its hydrolysis. The desalting process contributed to produce worse results, but the sample LGG E DS sample reached the maximum log CFU/g at 24h and the lowest pH. In general, the enzymatic treatment would be the most suitable option if short fermentation times are sought. However, starter BY could be used without adding enzymes, in longer fermentations reaching a good mi-crobial growth. More studies are needed to evaluate the nutritional, sensorial and organoleptic beverage properties, as well as the microbial evolution during their storage.