Optimization work for recombinant processes with P. pastoris is generally performed in bioreactors by the fed-batch strategy. The basic scheme follows in principle the original protocol of Brierley and coworkers [13] . A glycerol batch phase is followed by a transition phase and by a methanol induction phase [14] . Thereafter, methanol is added continuously. Different variations of this strategy have been proposed, mostly evaluated as being advantageous for a specific protein (comprehensively reviewed by [2] ).