Spectrophotometric Method for Rapid Detection of Bacteria
The catalase activity of intact cells was investigated with the UV spectrophotometry to realize the rapid detection for bacteria(E.coli DH5αas a model).With the addition of hydrogen peroxide to the bacteria solution,the catalase of the bacteria would decompose the hydrogen peroxide,which followed the first-order kinetic.The first-order rate constant that reflected the bacteria concentration was calculated according to the absorbance change of hydrogen peroxide at 240 nm.The results indicated that there was a linear relationship between the rate constant and the E.coli concentration in the range of 5.7×10 6 -5.7×10 7 cfu/mL;the catalase activity of intact E.coli was 4.2×10 -13 L/(s·cell).This method could be used to detect the bacteria of 5.7×10 6 cfu/mL within 5-10 min.