Prediction of photosynthetic production rate of ethylene using a recombinant cyanobacterium

A model of substrate inhibition for enzyme kinetics is applied to photosynthetic production of ethylene by a recombinant cyanobacterium, which exhibits light inhibition behavior. Kinetic parameters of the model were evaluated from a linear plot of the data. Parameter values obtained in this way described well the light-intensity dependence of ethylene production rate. The inhibition model was then extended to predict the production rate at higher cell concentrations, taking account of the light absorption effect by the bacteria. An explicit expression for the production rate was derived and the predicted results agreed with experimental data. An expression is also derived for the optimum light intensity which will result in a maximum production rate. In addition, predicted features of light-intensity dependence of total production conformed to reported results of another photosynthetic product. The approach of the present work may be applicable to a number of other photosynthetic processes. Copyright 1999 Academic Press