Characterization of the phenotypic diversity of Komagataella strains for biotechnological applications

Abstract

The methylotrophic yeast Pichia pastoris is an important model organism for heterologous protein production. It belongs to the genus Komagataella, which is now divided into seven different Komagataella species. The main focus of this thesis was the characterization of growth and mating behavior of 25 different Komagataella strains. The growth characterization was realized with spotting assays using various carbon sources and stressors at two different temperatures, which gives a good selection of strains with useful properties for further analysis. Not only growth behavior but also mating between different strains and species is not well studied for Komagataella. For the mating experiments, strains were transformed with a vector containing antibiotic resistance and a reporter protein, either geneticin/eGFP or nourseothricin/mCherry. Characterization of mating and the ability to undergo meiosis is essential for strain characterization, especially in terms of species definition but also for biotechnological applications. Based on the obtained results, two strains with differences in xylose utilization were mated, and growth curves of the F1 generation were recorded. This small-scale experiment showed the possibility to create descendants harboring the benefits of both parents as well as the analysis of complex traits and their genetic background.