Biorefineries consider lactic acid as one of the most promising platform chemicals which are being extensively used in a wide range of food and nonfood applications. Since lactic acid is produced via biotechnological processes, the microbial strains are in the focus of interest, besides all the other aspects of raw materials, fermentation mode, etc.
Microorganisms, which are able to produce lactic acid and organic lactates, are systematically classified and morphologically and biochemically characterized, and their different metabolic pathways for the formation of various lactic acid enantiomers are described in detail. The genera Lactobacillus and Bifidobacterium are regarded as well as the order of the Bacillales. In addition, the important individual yeasts, moulds and other bacteria were also characterized.
The present review work is summarized on the fermentation systems used for the biotechnological production, the various raw materials and applications of lactic acid and organic lactates. Future developments in this area with respect to the strain selection and modifications, genetic-engineering approaches, carbohydrate sources and their pretreatment, fermentation techniques and the downstream processing options are discussed.