“Alpha hydroxy acids (AHAs) have received wide attention in cosmetic and animal feed-industries. HMB, an important member of the AHA group, is the hydroxy analog of methionine. Methionine is a limiting amino acid for a number of animal species. Unlike free methionine, HMB shows resistance to degradation and superior bioavailability upon supplementation to ruminants and avian species.
Other AHAs, such as lactic acid and malic acid are increasingly being used in the cosmetic, food and beverage industries. AHAs contain one carbon of asymmetry and exist in two enantiomeric forms. Chemical synthesis of AHAs generally yields a racemic mixture which contains 50% L and 50% D forms. Biological world is chiral in nature, i.e. it prefers either the L or D form. Therefore, one would expect a difference in activity of L-enantiomers and D-enantiomers of HMB and other AHAs in biological systems. However, due to limited availability of pure HMB enantiomers and the cost factors associated with their production, differences in activity for HMB enantiomers have not been discerned. It is imperative that a cost effective processes for efficient production of enantio-pure or enantio-enriched AHAs be designed and implemented.
This study was aimed at development and evaluation of an efficient preparatory scale approach for isolation of AHA enantiomers. The process involved selective hydrolysis of AHA-esters in an aqueous system with immobilized enzymes. The free enzyme catalyzed enzymatic reactions were slow compared to those catalyzed with the immobilized enzymes. Chiral LC-MS and LC results for enantio-enriched HMB and lactic acid showed that enantio-purity of > 95% can be readily achieved with lipase immobilized in sodium alginate-gelatin blended beads”--Abstract, page iii.
Ludlow, Douglas K.
Nam, Paul Ki-souk
Chemical and Biochemical Engineering
M.S. in Chemical Engineering
University of Missouri--Rolla
ix, 60 pages
© 2005 Samit Kapoor, All rights reserved.
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Alpha hydroxy acids
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Kapoor, Samit, "Enantio-enrichment of alpha-hydroxy acids through immobilized-lipase catalyzed hydrolysis of their esters" (2005). Masters Theses. 5849.
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