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Assistant professor Claudia Schmidt-Dannert and grad student Erin Marasco shuffle bacterial genes to produce new avenues of biocatalysis, resulting in novel carotenoids, or plant pigments, that have a variety of potential uses in food and medicines.
The emerging uses of biocatalysis
From salad containers to potent new drugs
By Deane Morrison
From M, spring 2005
A tank truck full of pesticide skids and flips over in a rainstorm, spilling a thousand gallons of concentrated weed killer onto a field. Before the day is out, however, environmental managers arrive and treat the field with bacteria that love to chow down on the weed killer, and in a couple of months the soil has been decontaminated. The scenario is fictional, but it's not too far removed from the real-life experience of U of M professors Lawrence Wackett and Michael Sadowsky, two researchers in the burgeoning field of biocatalysis. They have cleansed soil of atrazine--a common herbicide--using bacteria that ingest the chemical and break it down into harmless byproducts. They have expanded their work to include the bacterial detoxification of mercury compounds and the genetic engineering of plants to remove and detoxify herbicides in the soil near waterways.
In the Center for Drug Design, senior associate director Ramaiah Muthyala is looking for new ways to inhibit the growth of virulent bacteria that are resistant to vancomycin, an antibiotic of last resort.Cleaning up toxic spills is just one of many facets of biocatalysis. "You can make things or break things [with biocatalysis]," says College of Biological Sciences dean Robert Elde. The term itself refers to using enzymes, usually from bacteria and yeast, to break down pollutants or to turn plant material into useful products while using less energy than traditional methods. Enzymes are the catalysts--they make chemical reactions happen much faster and at much lower temperatures, but are not themselves altered by the reactions. Biocatalysis holds promise for all kinds of new materials, like replacements for vinyl car upholstery or cotton that grows in a variety of colors--all stain- and wrinkle-resistant, of course. From University graduate Patrick Gruber (Ph.D. '88) comes an example of biocatalysis based on the ability of bacteria to ferment cornstarch, a process that produces lactic acid. Gruber found a way to produce different forms of plastic from chains of lactic acid. Called polylactic acid (PLA), the plastic is completely biodegradable and is used in making cups, plates, and even clothes. Gruber is vice president and chief technology officer of Cargill Dow LLC, the company that markets the product as NatureWorks(tm) PLA or Ingeo(tm) Fibers. Biocatalysis projects at the U span several colleges and involve multiple faculty members. In the Center for Drug Design, senior associate director Ramaiah Muthyala is looking for new ways to inhibit the growth of virulent bacteria that are resistant to vancomycin, an antibiotic of last resort. Vancomycin works by preventing bacteria from building cell walls and protecting themselves. To do so, it must first get into the cell walls, but resistant bacteria use an enzyme that prevents them from absorbing vancomycin. Muthyala wants to destroy or inhibit this biocatalytic process. Some researchers are modifying genes and enzymes to create new biocatalytic capabilities. In the Department of Biochemistry, Molecular Biology and Biophysics, assistant professor Claudia Schmidt-Dannert works with Wackett on engineering bacteria to produce compounds useful in detoxifying solvents like carbon tetrachloride and chloroform. Another biochemist, Romas Kazlauskas, is researching ways to use enzyme catalysts in place of the industrial manufacture of pharmaceuticals in order to deliver greater product purity and specificity. The Department of Bio-based Products (formerly wood and paper science), is exploring such things as making paper from nonwood fibers or biodegradable plastics from lignin, a tough-to-degrade constituent of wood. The University packaged the President's Interdisciplinary Initiative on Biocatalysis, now two years old, along with three other initiatives--Healthy Foods, Healthy Lives; Translational Research in Human Health; and Brain Function Across the Lifespan-as part of its biennial request under the heading "Biosciences for a Healthy Society." The University has requested, and Governor Tim Pawlenty has recommended, funding increases of $12 million for the package in each year of the biennium. With its strength in bio-based sciences and technology, the University is poised to make the state a leader in biocatalysis industries, using natural processes to create new products with less environmental impact. As China and other large nations modernize, finding ways to make energy, products, and materials by less energy-intensive means becomes more important than ever.