Alternative PCR-Based Approaches for Generation of Komagataella phaffii Strains

Komagataella phaffii (Pichia pastoris) is a widely known microbial host for recombinant protein production and an emerging model organism in fundamental research. The development of new materials and techniques on this yeast improves heterologous protein synthesis. One of the most prominent ways to enhance protein production efficiency is to select K. phaffii strains with multiple expression cassettes and generate Mut(S) strains using various vectors. In this study, we demonstrate approaches to expand the applications of pPICZ series vectors. Procedures based on PCR amplification and in vivo cloning allow rapid exchange of selectable markers. The combination of PCR amplification with split-marker-mediated transformation allows the development of K. phaffii Mut(S) strains with two expression cassettes using pPICZ vectors. Both PCR-based approaches were applied to efficiently produce interleukin-2 mimetic Neo-2/15 in K. phaffii. The described techniques provide alternative ways to generate and improve K. phaffii strains without the need for obtaining new specific vectors or additional cloning of expression cassettes.