Production of Optically Pure Lactic Acid for Bioplastics
Amira M. Hamdan and Kenji Sonomoto
from: Lactic Acid Bacteria and Bifidobacteria: Current Progress in Advanced Research (Edited by: Kenji Sonomoto and Atsushi Yokota). Caister Academic Press, U.K. (2011)
Lactic acid has long been used for the fermentation and preservation of foodstuffs for human consumption. Lactic acid has 2 optical isomers: L(+)-lactic acid and D(-)-lactic acid. Lactic acid is classified as GRAS (generally recognized as safe) for use as a food additive by the US FDA (Food and Drug Administration), but D(-)-lactic acid is known to be harmful to human metabolism at times, and it can result in acidosis and decalcification. The optical purity of lactic acid is crucial to the physical properties of poly(lactic acid) (PLA), and an optically pure L(+)- or D(-)-lactic acid, rather than racemic DL-lactic acid, can be polymerized to a highly crystalline PLA that is suitable for commercial uses as a bioplastic. Therefore, the biotechnological production of lactic acid has received a significant amount of interest recently, since it offers a solution to the environmental pollution caused by the petrochemical industry and an alternative to petrochemical resources, which are limited read more ...