2.4. Metabolite Extraction for Metabolomics

Metabolite extraction was performed by washing the cells twice with PBS (4 °C), followed by incubating the cells in 300 μL of methanol/water (80/20, −80 °C) on dry ice for 20 min. Next, cells were scraped twice (once in an initial 300 μL after which the remaining cells were scraped in an additional 200 μL of methanol/water (80/20, −80 °C), after which the methanol sample was collected into a 1.5 mL Eppendorf tube. The samples were centrifuged (16,200× g, 10 min, 4 °C), whereafter, the supernatant was transferred to a new Eppendorf tube. The cell extracts were stored at −80 °C until further use.