Baking yeast Saccharomyces cerevisiae were suspended in saline soln. (dry matter concn. 0.03-0.05 g/cm(3)) and then disintegrated in ultrasonic homogenizer to release nucleic acids. The degree of disintegration was detd. by measuring the absorbance of light at a wavelength of 260 nm. Linear of first order differential equations were used to describe the kinetics of disintegration (coeff. of determination 0.97-0.99). An increase of suspension concn. resulted in increasing the process rate.