LINDO Helps de Bugs

We are always happy to hear from users regarding successful or novel applications of optimization. When we see both, we are doubly delighted. Such is the case of the application kindly brought to our attention by Carlos M. Gonzáles Alcón of Universidad de La Laguna. His paper, authored with Torres, N.V., E.O. Eberhard, and F. Rodríguez, appeared in the September 1997 issue of Biotechnology and Bioengineering and was titled, "An Indirect Optimization Method for Biochemical Systems: Description of Method and Application to the Maximization of the Rate of Ethanol, Glycerol, and Carbohydrate Production in Saccharomyces cerevisiae."

The use of microorganisms, such as yeast, for the production of useful substances like alcohol and antibiotics is common in the amount of various enzymes present. One particular model of such processes involves constraints containing products of variables. By taking logarithms, Prof. Alcón converted the model to a linear program and used LINDO to determine appropriate levels for various enzymes. Increased production rates of a factor of 3 were typical. A system was designed whereby Mathematica generated input files for LINDO to obtain the optimum profile of enzyme activities. An attempt to obtain the profile with random mutations and screening would have been very expensive and time consuming.