The commonly used methods for bioconversion kinetic Parameter ident ficatioii are linear plotting and nonlinear regression. However, linear ploning methods generally require considerable experimentation, and nonlinear regression can lead to "local optimization" because the obtained parameters del)end heavily on given initial values. In this article, a new and reliable nonlinear regression -based al)I)roach to bioconversion kinetic parameter estimation is reported. BY obtaining prclitninar.y values of kinetic paratneters on a stel)-b - v-step basis, the number Qf estimated parameters in each stel) can be reduced to 3 or 4. These preliminary values can then be used as initial guesses jbr the final parameter estimation via nonlinear regression. Compared with the linear plotting method, the proposed apj3roach can significantlY reduce the number of experiments required fior kinetic parameter e jimation. The tran,%ketolase catalyzed sYnthesis of 1,3-dih,)7,li-o-K,I)eiit(iii-2-oiie fi-om prop-ionaldehYde and P-hydroxypyruvate i. s used as an experimental exany)le to illustrate the al)proach. (c) 2008 Anlerican Institute of Chernical Engineers.