Sunday, April 29, 2007

Thermodynamic measurements and data for bioprocess engineering and for the production of biofuels

Robert N. Goldberg and Yadu B. Tewari. Biochemical Science Division, National Institute of Standards and Technology, Building 227, Room B218, Gaithersburg, MD 20876

The combined use of equilibrium and calorimetric measurements coupled with thermodynamic modeling calculations enables the characterization of the thermodynamics of enzyme‑catalyzed reactions.  The primary information obtained include equilibrium constants, enthalpy changes, and entropy changes for the reactions of interest.  This allows one to predict the position of equilibrium of these and related biochemical reactions over wide ranges of temperature, pH, and ionic strength.  This, in turn, can be used both to predict the feasibility of possible reactions and to optimize product yields.  Some of the classes of reactions which have been studied include isomerization, hydrolysis, and phosphorylation of sugars, and ammonia and water elimination reactions.  This methodology has been used to study many of the key industrial reactions including the conversion of glucose to fructose, catalyzed by glucose isomerase, and the conversion of trans‑cinnamic acid and ammonia to L‑phenylalanine, catalyzed by L‑phenylalanine ammonia‑lyase, and the hydrolysis reactions of a variety of di- and oligosaccharides.  The latter reactions are of particular interest for the production of biofuels.  We have also studied enzyme-catalyzed reactions carried out in organic solvents and in super-critical carbon dioxide.  The experiments have been coupled with a substantial effort aimed at a critical compilation and evaluation of all available thermodynamic data for enzyme‑catalyzed reactions(see:



Web Page: