Gravimetric Determination of Polyol Lipids

For polyol lipid determination, culture broth was centrifuged (5 min, 17,000 ×g). The cell pellet and polyol lipid were resuspended in acetonitrile. After another centrifugation step (5 min, 17,000 ×g), the acetonitrile, including dissolved polyol lipid, is separated from the cell fragments. The determination is carried out gravimetrically by evaporating the acetonitrile in pre-weighed glass vials using a speed vac at medium temperature (Savant Instruments, Speed Vac SC-100, Farmingdale, New York, United States). All wells from cultivations in MTPs undergo complete processing, followed by an additional acetonitrile rinse. After rinsing, the acetonitrile was used to resuspend the cell pellet, and polyol lipid after the first centrifugation step. In the case of samples obtained from the bioreactor, 1 mL of culture broth is utilized for each sample, with an accompanying 1 mL of acetonitrile.