An unstructured macrokinetic model for heterologous production of Rhizopus otyzae lipase (ROL) by a Pichia pastoris PAoxi based system was developed. Mean specific rates and state variables for various fed-batch cultures, under methanol limited and nonlimited conditions were used for modeling. The most representative kinetic functions (viz., Monod, Haldane, Pirt and Luedeking-Piret) were used for the specific rates of cell growth (u.), substrate consumption (qs) and product formation (qp). The performance of two different process models was assessed via simulation tests, using an overall validation procedure. The best model describes the cellular growth by a non-monotonic substrate function, substrate uptake via Pires equation and product formation through a Luedeking-Piret equation. A comparative meta-analysis of heterologous protein production of various target proteins by Pichia pastoris under A0X1 promoter was conducted and a general strategy for improving protein production from process kinetics was developed as a key to bioprocess optimization. (C) 2014 Wiley Periodicals, Inc.