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Technology Transfer for Aroma Chemical Research
By: Rich Boden, senior research fellow, IFF
Posted: March 5, 2009
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Utilizing chlorophyll and enzyme catalysts, plants transform carbon dioxide extracted from the air, water from the soil, and energy from the sun to create complex life-sustaining chemicals, as well as the essential oils and aroma chemicals employed in perfumes for products ranging from home care to fine fragrances.
Microbiologists use bacteria as the “chemical reactor and catalyst” for the enzymatic process known as fermentation. From this “natural” and sustainable chemistry, we derive functional organic chemicals which represent finished products or the raw materials for aroma chemicals. For example, scaleriolide, an intermediate for the synthesis of IFF ingredient Amberiff,a is the result of the fermentation of Scaleriol (IFF, US5,212,078) in the presence of Cryptococus albidus ATCC 20918.
Molecular biologists and enzymologists are now intensively researching ways of using recombinant microorganisms, enzymes or plants as sustainable sources of highly desirable aroma chemicals. Extensive research, especially in the area of pharmaceutical synthesis, is currently underway to identify recombinant processes that can be used in place of hazardous reagents and chemical processes. These designer reagents may be the sustainable key to a wealth of important naturals as well as chiral or optically active fragrance ingredients.
For instance, enzymatic processes produce chiral or optically active ingredients. A chiral ingredient can exhibit different odor profiles and can be best explained as the difference between your right and left hands. Although they appear to be the same, your palms are pointed in opposite directions. Molecules possessing a right or left “handedness” will rotate light to either the right or the left direction. This is exemplified by the odors of d-carvone, a right-handed molecule possessing the odor of caraway seed, and l-carvone, a left-handed molecule which has the odor of spearmint.
In its simplest form, the synthesis of an aroma chemical can result in the formation of an equal number of right- and left-handed molecules (defined as a racemic mixture). Since desired biological activity is usually associated with only one form (right- or left-handed), pharmaceutical research has focused on synthesizing molecules of specific rotation. To this end, a number of catalysts have been created that give primarily one form over the other. Fragrance chemists are utilizing this chemistry to exclusively create the desirable component of a racemic mixture. Since these catalytic methods create the molecule with the desired odor profile, waste and environmental impact are reduced.