Oxygen transfer model in recombinant <Emphasis Type="Italic">Pichia pastoris</Emphasis> and its application in biomass estimation

An oxygen transfer model was established for Pichia pastoris growing on glycerol and methanol in a stirred tank bioreactor and expressing a recombinant human serum albumin (rHSA). This was based on pseudo-steady state mass balance, where the volumetric O₂ transfer coefficient, k _L a, was estimated as a function of power input per unit volume and aeration rate. Under pseudo-steady state, the O₂ transfer rate model matched the O₂ uptake rate obtained from a previous macrokinetic model. This procedure was also applied to estimate biomass concentration by using the on-line rolling identification approach.