ATP 2G is now a standard tool recommended for:
IDENTIFY ALL MICRO-ORGANISMS
IN JUST 3 MINUTES SPEED
WITH ATP 2G!
Second generation ATP technology (ATP 2G) determines the quantity of adenosine triphosphate (ATP) present in a water or fluid sample.
Like DNA (deoxyribonucleic acid), ATP is characteristic of living things. Essentially, ATP acts a key element in energy metabolism by serving as an energy transporter. Determining the amount of this molecule allows quantification of all living micro-organisms present in a liquid environment: bacteria, fungi, yeast, protozoa, algae, diatoms and other planktonic organisms.
ATP detection involves enzymatic measurement using an enzyme produced by biotechnological methods: luciferase (copied from a well-known luminescent insect: the firefly).
As its name indicates, this enzyme produces light in the presence of luciferin and ATP. The amount of light energy released is directly proportional to the quantity of ATP present and thus the number of cells present in the sample.
After removing a sample of the fluid to be analyzed, the ATP is extracted from the cells in the sample via cell lysis (enzymatic digestion of the cell walls of bacteria, fungi, animal cells or plant cells). The cell extract is then combined with a solution containing luciferase and luciferin (Luminase™). The bioluminescence intensity is then measured using a special device called a luminometer (LuminUltra™), recent versions of which are compact and easily transportable.
Using the recommended ATP standards (UltraCheck™ system), the user can easily quantify the ATP concentration in picograms (pg ATP/mL) and determine the number of cells present in the samples in Micro-organism Equivalents (ME/mL). These units are not always proportional to the traditional CFUs (colony forming units) obtained by culture-based methods because ATP-metry detects a much wider range of microbial life.
The first ATP-metry tools appeared in the 1970s. They became more widely available during the 1980s and 1990s and were relatively successful despite limited applications.
• Microfiltration : inserting a microporous membrane allows viable cells to be retained, while residual compounds that could interfere with the luminescent signal are eliminated. This minimizes interference and background noise. Microfiltration provides two additional major advantages:
- concentration of the ATP content of a large sample (up to 100 mL);
- separation of free extracellular ATP (released by dead cells) from intracellular ATP (contained in living cells).
These features greatly increase the sensitivity and accuracy of the measurement. The level of stress and cell death in a microbial population within a network, for instance after a disinfection procedure, can also be characterized.
See the Biomass Stress Index™ calculation.
• Cell lysis step : the enzyme cocktail (UltraLyse™) has a wide range of action and enhanced activity, and can extract up to 99.99% of the cellular material. The ATP measurement is more representative of the actual biological content.
• Standardization step : the standard curve is established using a standard range of increasing quantities of ATP (UltraCheck™). Calibration of the device generates a conversion scale between the physical measurement (RLU - Relative Light Units) and a biological measurement (pg ATP/mL or ME/mL). The results are therefore more relevant. Most importantly, this conversion into biological units enables comparisons to be made between measurements taken by different luminometers at different sites or different time points (data in RLU can only be compared within a single system). This optimizes data management (historical, comparative) for the network user.