AbstractBiomass is a renewable and CO2-neutral source of energy having the drawback of low energy density. The energy density can be augmented by the production of bio-oil through fast pyrolysis. The high content of water-extractable organic acids (oxygenates) in bio-oil is problematic in fuels. Cultivation of Saccharomyces cerevisiae for the consumption of these undesirable components can be used to upgrade the bio-oil. It was found that the bio-oil water phase can support the growth of S. cerevisiae at concentrations up to 20 vol. % under aerobic conditions. The oxygenates formic acid, acetic acid, and propionic acid had a promoting effect for the cultivation of S. cerevisiae in the following order: acetic acid > formic acid > propionic acid. However, phenol, p-cresol, and furfural inhibited the growth of S. cerevisiae. Kinetic analysis of the consumption of oxygenates showed that the regulation of S. cerevisiae was in accordance with a logistic function model.