' * ~3 + DIELECTRIC SPECTROSCOPY: A RAPID: :.......L METHOD FOR THE DETERMINATION OF 3 SOLVENT BIOCOMPATIBILITY DURING

Dielectric spectroscopy provides a convenient means of determining the degree of intactness of biological cells. 4-terminal dielectric measurements of suspensions of Saccharomyces cereviriae at 0.4MHz show that, as with all other biological cells, these organisms possess a substantial B-dispersion. The additional of octanol to such suspensions causes a rapid decrease in the electrical capacitance of the suspension, which parallels the cellular viability as determined by methylene blue staining. The kinetics of cell death are determined in part by the rate of dissolution of the organic solvent in the aqueous phase. The toxicity of several organic solvents to S. cereviriae is studied using this technique, and is found to be dependent upon the polarity of the solvent. The present method provides a simple and rapid means for assessing the biocompatibility of solvents used in biotransformations. KEY WORDS Organic solvents, biotransformations, bioconversions, toxicity, dielectric spectroscopy