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Synthesis

Biocatalysis Steps Forward

by Rudy Baum
August 14, 2006 | A version of this story appeared in Volume 84, Issue 33

This week's cover story focuses on the use of biocatalysis in chiral synthesis (see page 15). Because so many pharmaceutical molecules contain one or more chiral centers and because regulatory requirements increasingly demand high enantiomeric purity in pharmaceuticals, efficient chiral synthesis has become essential for manufacturers of fine chemicals. As C&EN Senior Correspondent Ann Thayer points out in the cover story, drug manufacturers are adopting biocatalysis as an important tool in chiral catalysis, but the shift has sometimes been grudging.

"Chemists have been practicing organic chemistry for hundreds of years; microbes have been at it even longer," Thayer writes. "Microbial and other enzymes are superbly enantio-, chemo-, and regioselective across a diverse range of reactions under mild conditions of pH, temperature, and pressure. Why, then, has it taken chemists so long to put aside a dislike of 'bugs' and use their enzyme catalysts?"

The answer to that question is complicated. In part, it has been due to inertia; in part, to biocatalysis having been oversold in the past. Tassos Gianakakos, senior vice president for business development at Codexis, told Thayer: "Our target market, for better or worse, has been relatively slow to adopt biotechnological approaches to traditional chemical process R&D. It's probably not surprising since there's been a lot of very good chemistry done over the past 30-40 years within pharmaceutical companies, and layered on top of that is the fact that, historically, biocatalysis hasn't delivered the promise."

Karen Holt-Tiffin, head of biocatalysis at Dowpharma, said, "The biggest hurdle is still trying to change the mind-set of the organic chemists so they are not worried about using enzymes and actually try them as a method of choice."

There are certainly good reasons to turn to enzymes for chiral synthesis. Thayer writes, "Contributing to the growth of biocatalysis are cost pressures, lower R&D productivity, the need to address selectivity and complex chemistry for high-purity chiral compounds, and a desire to access greener technologies." She points to numerous companies such as BASF, DSM, Degussa, Lonza, NPIL Pharma, and many Japanese companies that have long histories of using large-scale fermentations and biotransformations. Other fine chemicals companies such as Dowpharma, Cambrex, and Archimica have added biocatalysis capabilities largely through acquisitions.

Having established biocatalysis platforms allows fine chemicals producers to respond quickly to customer requests, Thayer writes. Techniques have been developed to make it easier to find enzymes that can carry out a given reaction, and once an enzyme is identified, development can be much more rapid than many people realize.

Enzymes certainly won't replace traditional catalysts in all chiral syntheses, but biocatalysis is clearly another powerful tool in the fine chemicals toolbox.

Golden Opportunity

 

The American Chemical Society's fall national meeting in San Francisco is only a month away. The full technical program will appear in next week's issue.

In addition to the wide range of technical and social events traditionally associated with an ACS national meeting, attendees in San Francisco will have an opportunity to give something back to the host city. In a Presidential Event on Saturday, Sept. 9, ACS is partnering with a community service organization, Hands On Bay Area, to organize a number of community projects for meeting attendees.

Project sites include the San Francisco Zoo, the San Francisco Food Bank, and parks. The physical effort will vary, so there will be a variety of activities to accommodate volunteer capabilities and interests. For more details, please see ACS Board member Bonnie A. Charpentier's comment in the June 26 issue (page 47). To register, go to chemistry.org.

Thanks for reading.

Views expressed on this page are those of the author and not necessarily those of ACS.

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