Polyethylene glycol (PEG) is polymer that was used to replace NaCl (reference media) as an osmotic stress agent for the synthesis of erythritol by the osmophilic yeast Yarrowia lipolytica. Two strains, the wild-type strain IMUFRJ 50682 and the lab strain W29, were grown in the presence of PEG of different molecular weights. For strain IMUFRJ 50682, the erythritol titer was increased by 40% in the presence of PEG2000 as compared to the reference media (with NaCl). A similar increase was also observed for strain W29, except that it occurred in the presence of PEG6000. Moreover, in those experimental conditions neither strain produced mannitol, in contrast to the control medium. These results highlight that PEG could be used to increase erythritol productivity and to simultaneously inhibit mannitol synthesis, representing a good substitute for NaCl as an osmotic stress agent.
Keywords: Erythritol; Glycerol; Mannitol; Osmotic pressure strategy; Polyethylene glycol (PEG); Yarrowia lipolytica.