ATP Conversion References

► 1 femtogram of ATP is equivalent to 1 E. Coli-sized bacteria

This is a frequently cited conversion and has been observed by many researchers, including Jim Cairns (LuminUltra’s Director of Product Development). There are a variety of ATP-to-cell number correlations that have been done by various researchers using pure cultures.

The reference citing the above conversion can be found in an October 2001 Application Note by Wolf and Derringer entitled “Rapid quantification of viable bacteria in water using an ATP assay”. The precise citation is as follows on the second page:

It is known that the average ATP content in one bacterial cell is about 10-15 g (1 fg)

Reference 4 is cited as the source of this conversion:

Crombrugge J, Waes G. ATP method. In: Heeschen W, ed. Methods for assessing the bacteriological quality of raw milk from the farm. Brussels: International Dairy Federation, 1991: pp. 53–60.

► 1 part ATP is equivalent to 250 parts biomass carbon

The reference citing this conversion can be found in a July 1978 paper by Holm-Hansen entitled “Chemical and biological characteristics of a water column in Lake Tahoe”. This reference states:

ATP (in micrograms per liter) was converted to organic carbon in living cells by multiplying by 250 (Holm-Hansen 1970); this carbon value was then multiplied by 10 to give biomass wet weight ( microgram liter-l).

The reference (Holm-Hansen 1970) is listed as:

Holm-HANSEN, 0. 1970. ATP levels in algal cells as influenced by environmental conditions. Plant Cell Physiol. 11: 689-700.

► Dry biomass is approximately 50% carbon

This is a very common conversion found in many industry reference books. You can find it in the Metcalf & Eddy handbook of wastewater treatment. In the 4th Edition, it can be found on page 554 in table 7-4.