SUGAR fatty acid esters (SFAE) are widely used due to their non-toxic and non-ionic attributes. Certain sugar esters are also antimicrobial making them suitable for pharmaceutical uses. Conventional chemical synthesis of SFAEs, however, require high levels of energy and may produce toxic by-products. As such, lipase mediated synthesis is seen as a less energy-hungry and more environmentally-safe alternative.
Sugar fatty acid esters (SFAE) are created by the esterification (reaction between an acid and another type of chemical) between a sugar and a fatty acid.
SFAEs are tasteless, odourless, non-toxic, non-ionic, antimicrobial and biodegradable surfactants (lowers the surface tension between two liquids, a gas and a liquid or a liquid and a solid).
These attributes allow them to have broad applications in the food, pharmaceutical, detergent, agricultural, fine chemical, and personal care industries. Certain sugar esters even have insecticidal properties.
Though sugar esters can be produced through chemical processes (i.e. esterification), this method is energy-hungry, has little selectivity, produces toxic substances as a by-product, and the product itself maybe heterogenous, containing a mixture of different chemicals in varying states of esterification.
As such, enzyme-based methods are preferred as an alternative, particularly lipase mediated synthesis which forms the basis of a study conducted by a research team led by Universiti Malaya’s Prof. Mohamad Suffian Mohamad Annuar of Institute of Biological Sciences.
Lipases are widely used in organic synthesis of specialty chemicals. In the case of SFAEs, lipases are almost always used in an immobilized form, typically attached to porous beads of a plastic material.
The researchers aimed to determine certain factors that affect lipase mediated synthesis such as temperature and water activity.
Compared to chemical synthesis, lipase mediated synthesis, like other enzyme-based methods, requires a lower temperature to begin the reaction thus requiring less energy, does not produce harmful by-products, offers a high degree of selectivity and typically produces a monoester with little traces of other products.
Lipases can provide potential for enhancing enzyme thermostability, improving its solvent tolerance, increasing its specificity and heightening its activity.
Lipase mediated synthesis can provide improved access to many useful commodities including drug-carriers, food esters, cosmetics and fragrance esters. However, certain improvements can be made to enhance the lipases’ effectiveness and suitable non-aqueous and safe solvents must be found for use in this reaction.
Gumel, A.M., Annuar, M.S.M., Chisti, Y., Heidelberg, T. (2011) Lipase mediated synthesis of sugar fatty acid esters. Process Biochemistry, 46 (11), 2079-2090. http://dx.doi.org/10.1016/j.procbio.2011.07.021