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There are several important features a microorganism used for the production of lactic acid must have in order to be industrially attractive:

 high productivity to reduce fermentation time,

 high conversion yield to reduce carbohydrate costs,

 ability to use cheap sources of nutrients to reduce nutrient costs,

 high‐end concentration to reduce evaporation costs,

 low amount of by‐products to increase purification yield, and, of course,

 the organisms must be robust with regard to contamination and infections.

Every microorganism has its own benefits and drawbacks, but lactobacilli (present in many food fermentations) and Rhizopus (a fungus) are the most reported [40]. Besides lactobacilli and Rhizopus, Streptococcus, Pediococcus, Sporolactobacillus inulinus, Bacillus coagulans, and several yeasts are mentioned in the excellent overview by Vaidya et al. [41].

Lactobacilli generally have high productivity, but special and often expensive nutrient requirements. Rhizopus needs much less nutrients, but has a lower yield, needs oxygen, and its morphology is sometimes difficult to handle. Of course, via genetic manipulation, researchers have tried to make an ideal lactic‐acid‐producing microorganism.