Indirect Methods

Concentration of viable cells is measured in terms of oxygen upt4ke rate (OUR), carbon dioxide evolution and ATP production rate (APR).

A constant called specific oxygen uptake rate (SOUR) or specific ATP production rate (SAPR), which is determined experimentally is made use 0 fin getting cell concentration, if 0 UR and APR are known.



However SOUR and SAPR fluctuate with the physiological state of the cell.