Critical analysis of quantitative indicators of cell disruption applied to Saccharomyces cerevisiae processed with an industrial high pressure homogenizer

A comparison of quantification techniques was performed on suspensions of Saccharomyces cerevisiae which had been disrupted with a high pressure homogenizer. The quantification techniques included cell counting, monitoring protein release, UV absorbance, turbidity, sample mass loss analysis, variations in viscosity and measuring the particle size distribution of the homogenate. It was found that all quantification techniques resulted in similar relationships between the measured extent of disruption and number of passes through the homogenizer. The data from all techniques (except particle sizing) could be fitted to simple exponential decay models at various homogenization pressures. Turbidity, particle sizing and UV absorbance generally gave more conservative estimates of the extent of cell disruption compared to protein release and cell counting. Measuring both the turbidity and monitoring the release of cellular metabolites using UV absorbance gave simple, reliable and reproducible measures of disruption and were identified as being the most applicable to on-line disruption monitoring.

► A variety of techniques are available for estimating the extent of cell disruption.
► All methods tested could be fitted to simple exponential decay models.
► Cell counting is the most accurate method across the full range of disruption.
► Turbidity, particle sizing and UV absorbance were the more conservative indicators.
► Measuring sample turbidity or UV absorbance is suitable for online monitoring.