Aeration plays an important role in the production of glycerol by fermentation with yeast. Effective aeration depends on a number of factors, such as amount of air, fineness of air dispersion, rate of agitation, and time of gas-liquid contact. This investigation dealt with the effect of periodic variation in gas pressure on oxygen transfer measured by sulfite oxidation and glycerol fermentation in stirred tanks. The oxygen transfer rate measured with the sulfite oxidation method was improved by 20-30% under the condition of pressure pulsation (PP) at 30 degreesC. The yield and productivity of glycerol were increased by about 26 and 6.8%, respectively, in 48 h by employing a glucose concentration of 250 g/L with PP at 30 degreesC.