Comparative lipidomics of methanol induced Pichia pastoris cells at different culture phases uncovers the diversity and variability of lipids

Pichia pastoris is an attractive eukaryotic host widely employed in industrial biotechnology for protein production and biocatalysis, and oxidative stress and other harsh conditions were frequently encountered during the cultivation cycle, however, the global lipidomic profile change needed to be revealed. The present study aimed to discover the variation in P. pastoris lipids at different stages (lag, logarithmic, stationary, induction and decline phases) by a sensitive ultra-performance liquid chromatography/nanoelectrospray-mass/mass spectrometry. We identified 253 lipid species across 11 lipids classes, including glycerophospholipids, glycerolipids and sphingolipids. High diversity and flexibility of lipids (including the composition and relative intensity) were observed during different phases, especially when glycerol was shifted to methanol. Especially, the unsaturated-double-bonds containing lipids showed a close relationship with the change of carbon source, which also led to increase of oxidative stress. Additionally, the relative intensity of sphingolipids was increased obviously in decline phase, likely associated with cell apoptosis. The current study expanded our understanding of the cell physiology of P. pastoris through the lipid profile change and lay the foundation for chassis design strains in the future by engineering microbial membrane.