Enzymatic synthesis of PHAs using ionic liquids as solvents

POLY 350

Johnathan Gorke, gorke@cems.umn.edu, Chem. Eng. & Matl. Sci. and BioTechnol. Inst, University of Minnesota, 1479 Gortner Ave, St. Paul, MN 55108, Romas J. Kazlauskas, rjk@umn.edu, Biochemistry, Molecular Biology and Biophysics, and BioTechnology Institute, University of Minnesota, 1479 Gortner Avenue, St. Paul, MN 55108, and Friedrich Srienc, srienc@umn.edu, Chemical Engineering and Materials Science, and BioTechnology Institute, University of Minnesota, 1479 Gortner Ave, Minneapolis/St. Paul, MN 55455/55108.
Microorganisms make polyhydroxyalkanoic acids (PHAs) by polymerization of enantiomerically pure (R)-3-hydroxyalkanoates activated with Coenzyme A. Although this natural process can be reconstructed in vitro, it is prohibitively expensive since it requires enantiomerically pure precursors and formation of the Coenzyme A derivatives. We report an efficient alternative route to PHAs that eliminates the need for Coenzyme A derivatives. Lipases can catalyze the polymerization of 3-, 4- or 6-hydroxy acids or the corresponding lactones to PHAs in organic solvents. Unfortunately, precipitation of low molecular weight PHAs limits the molecular weight of such reactions. Recently, we found several ionic liquids that dissolve PHAs and also preserve the enzymatic activity of lipases. Lipase-catalyzed polymerization of lactones in ionic liquids yields high molecular weight homopolymers and copolymers of PHAs.
 

Biocatalysis in Polymer Science
8:30 AM-11:50 AM, Tuesday, 12 September 2006 San Francisco Marriott -- Salon 12/13, Oral

Division of Polymer Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006