Biocatalysts move into chemical and pharmaceutical industries
In some cases, biocatalysts can be superior to chemical synthesis. High selective stereo-selective enzymes for example can be applied for the production of chiral hydroxamic acids and amines.
In the past few years we learned to meet biocatalysts in various situations of every-day life: Enzyme containing detergents deliver ultra-clean washings. They remove stains from blood and egg as thoroughly as those from cacao and fat. Immobilized on bio-sensors they analyze reliably hazardous compounds in our environment or sugar concentration in the blood of diabetics.
More recently, even high-value compounds for chemical and pharmaceutical industries are being synthesized by enzymes or microorganisms. Especially for the synthesis of chiral compounds use of enzymes is growing steadily.
"Chiral molecules behave as two mirror images, they only differ in their three-dimensional structure" explains Dr. Hiltrud Lenke from the Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB. In most cases, however, only one of these variants is effective as pharmaceutical drug, as pesticide or as nutrient. The other "enantiomer" is useless/futile or even damaging health, as was true for Contergan. Therefore, the synthesis of these compounds has to be controlled, thus guaranteeing the production of the desired enantiomer only.
At the Fraunhofer IGB a novel chemo-enzymatic process for the synthesis of chiral amines has been developed. Amides are transformed to amines by the action of enzymes called amidases generating the desired enantiomer in a purity higher than 99 percent. This high purity is necessary as amines are often used as intermediates in drug synthesis.
Although there is a huge variety of stereoselective catalysts in nature, only a few are applied in synthetic chemistry. "The screening for biocatalysts suitable for the specific technical application often is very time- and cost-intensive", is the experience of Hiltrud Lenke. And many companies try to avoid this expensive screening.
Therefore, the IGB plans to offer enzyme screening with partly automated methods. "These methods may be applied in an analogous manner as they are in pharmaceutical drug screening. Aim of the project is automatical analysis of a sample resulting in the identification of the specific enzyme" is envisioned by the scientist.