Abstract: To evaluate the toxic effect of formic acid on Saccharomyces cerevisiae GGSF16, the influence of fomic acid at different concentrations on the growth and metabolism of S. cerevisiae were determined. The results showed that formic acid at 1.8 g/L significantly inhibited the growth of yeast cells, reduced ethanol production, and extended cell fermentation cycle. The contents of extracellular nucleic acid, protein and malondialdehyde, and the activity of intracellular hexokinase in the treated cells were 1.4, 1.67, 5.3 and 3.95 (P < 0.05) times as high as those in the control group, respectively. Scanning electron microscopic (SEM) images showed that a large number of wrinkles and cavities appeared on the surface of intact and smooth yeast cells, and that and cell-cell adhesion was observed. Fourier transform infrared spectra demonstrated that formic acid could destroy the cell wall and increase the permeability of the cell membrane, thus leading to the leakage of cellular contents and cell death finally.

Key words: formic acid; Saccharomyces cerevisiae; growth metabolism; cell membrane permeability