Improved ATP methodology for biomass assays

ATP methodology needs to be further standardized and improved in order to avoid the pitfalls that have sometimes hampered its application to biomass assays. The following steps have been reconsidered as far as the bacteriological applications is concerned:

• destruction of free and somatic ATP: replacement of apyrase by mammalian ATPase, more readily accessible to specific inhibition;
• extraction of bacterial ATP: protection of luciferase by lipids against inhibitory effect of cationic detergents with production of a constant light response.

New methods are proposed for the calibration of luminometers and for the matching of sample holders in multichannel instruments. The limit of sensitivity of ATP assays is discussed in the light of currently available reagents and instruments.