1991 Volume 32 Issue 2 Pages 71-77
A very rapid method for estimating viable cell counts of E. coli and yeast based on catalase assay using an oxygen sensor was developed.
In this study, catalase activity assay was conducted using a small closed reactor equipped with a sensitive oxygen sensor while nitrogen gas was introduced through a pipe. Assay was done at 30°C in a phosphate buffer solution (pH 6.0). The linear increase of dissolved oxygen which appeared 10 to 45 seconds after injection of H2O2 into the exygen-free sample solution in the reactor was recorded and catalase activity (decomposed μmol H2O2/sec/ml) was calculated from the rate of oxygen increase. The results of experiments on E. coli and yeast cell suspension showed a high correlation between catalase activity and cell count in the range of 103-107 cells/ml.
Our results suggest that the use of an oxygen sensor is an economical and a rapid method for estimating cell counts of E. coli and yeast.
