A simple structured model is proposed for the methanol production phase of the iduronate 2-sulphate sulfatase recombinant enzyme (IDShr) in Pichia patoris Mut(+). The model is mainly focused in oxidative stress phenomenon due to methanol consumption and based on extracellular experimental information and the basic knowledge of methanol metabolism in Pichia pastoris yeast (P. pastoris). The model's prediction shows a reasonable accuracy as compared with the experimental data. Likewise, it was proved that this model is able to simulate the production of other recombinant protein in P. pastoris.