Lactic acid by fermentation

Polylactide is the generaUy accepted term for highly polymeric poly(lactic acid)s. Such polymers are usuaUy produced by polymerization of dilactide the polymerization of lactic acid as such does not produce high molecular weight polymers. The polymers produced from the enantiomeric lactides are highly crystalline, whereas those from the meso lactide are generaUy amorphous. UsuaUy dilactide from L-lactic acid is preferred as a polymerization feedstock because of the avaUabUity of L-lactic acid by fermentation and for the desirable properties of the polymers for various appUcations (1,25). 

Saha, B. C., and Nakamura, L. K. 2003. Production of mannitol and lactic acid by fermentation with Lactobacillus intermedius NRRL B-3693. Biotechnol. Bioeng., 82, 864-871. 

Soetaert, W., Buchholz, K., and Vandamme, E. J. 1995. Production of D-mannitol and D-lactic acid by fermentation with Leuconostoc mesenteroides. Agro. Food Ind. HiTech., 6, 41-44. 

Scientific progress in more recent times has not only revealed the mechanisms of traditional bioprocesses, but has also improved the ability of bioprocessing to generate useful products. Advances in pure culture and other classical bacteriological methods initiated the first commercial production of lactic acid by fermentation in 1881 The subsequent development of the first cholera,... 

One example of fermentative bacteria is a group termed the lactic acid bacteria. These bacteria, which are commercially important in the cheese and dairy industry as well as in pickle and sauerkraut production, produce lactic acid by fermenting sugars. 

D-Lactide can be obtained if one has the appropriate biochemistry to produce the D-enantiomer of lactic acid by fermentation of carbohydrates. Copolymeiization of controlled mixtures of l- and D-lactides subsequently offers the advantage of precise control over PLA properties. Moreover, D-lactide is the monomer for the production of poly(D-lac-tide), which is able to form high-melting stereocomplex PLA via 1 1 racemic cocrystallization with P(L)LA, as will be discussed in Chapter 5 [89]. 

Lu, Z., M. Wei, and L. Yu. 2012. Enhancement of pilot scale production of L-(t>)-lactic acid by fermentation coupled with separation using membrane bioreactor. Process Biochem. 47 410-415. 

Lactobacillus spp are a large group of lactic acid bacteria that are all Gram-positive organisms, which produce lactic acid by fermentation. Lactobacillus is one of the largest genera and contains presently around 80 species (Giraffa et al., 2010 Satokari et al., 2003). 

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