DETERMINATION OF EQUIVALENT SIZE OF MICROBIAL CELLS FROM THEIR VELOCITIES IN HINDERED SETTLING

Abstract

The empirical formulas reported previously in the prediction of hindered settling velocities of fine particles in suspension were applied to the determination of equivalent size of specific microbial cells in gravitational as well as in centrifugal field. The agreement between the size determined so far from the velocities in hindered settling and that measured directly with a microscope seemed to be satisfactory in the case of yeast cells (Saccharomyces cerevisiae) and bacterial cells (Serratia marcescens) studied. The determination was also made using a strain of Actinomyces (Streptomyces griseus) and an activated sludge, both of which are usually complicated enough in shape compared with bacteria and yeast so that no quantitative studies have ever been made to assess their shape.If an attempt is made on transfer problems from/to microbial cells, the application of this sort of study will be useful.