ASSESSMENT OF CELL COUNTING METHOD BASED ON IMAGE PROCESSING FOR A MICROALGA CULTURE

Routine monitoring of microalgal growth requires the use of one of several methods such as cell counting under the microscope and measuring optical density (OD) with a spectrophotometer. Each of these methods has their advantages and disadvantages. For example, counting cells under the microscope can be time consuming, but it provides the best estimate of cell growth. Measuring OD is much quicker, however it doesn’t provide any information on cell numbers and debris in culture can interfere with OD measurements. Therefore, this study aimed to demonstrate the usefulness of an image processing approach for counting cells in a microalga culture. Results showed that highest correlations were observed between Utermohl cell counts and OD measurements (r=0.99), ImageJ cell counts and OD measurements (r=0.99) and between Utermohl and ImageJ cell counts (r=0.99). In the regression analysis, highest R2 values were obtained for Utermohl vs OD (R2=0.99) and ImageJ vs OD (R2=0.99). Counting algal cells with ImageJ allows the analyst to complete the procedure 4 times faster than with manual Utermohl procedure.