Quorum Sensing


Quorum Sensing (QS) is the mechanism by which bacteria regulate gene expression in accordance with population density using signal molecules.   

See (https://www.britannica.com/science/quorum-sensing). Quorum sensing is now referenced in thousands of bacteria-related articles, and over 300 signal molecules have been identified and some of them quantified. (1) Quorum sensing proceeds though four main steps:

  1. Synthesis of signal molecules (autoinducers)
  2. Excretion of the signal molecules
  3. At a certain concentration, activation of specific receptors
  4. Resulting activation of a certain gene expression

The fourth step results in the microbe behaving differently when in a quorum versus individually. The change in gene expression and behavior when in a “quorum” has been found to be important in: virulence, bioluminescence, biofilm formation (2) and others. 


The threshold concentrations needed for various bacteria to sense a quorum and change their behavior may not be known. Various analytical approaches have been used to try and quantify some of the signal molecules or autoinducers. As could be expected, QS signal molecule concentrations can be very low particularly when bacteria counts are low.  In reference 1, table 4 some peptides (chains of amino acids) used as signal molecules were analyzed and found to vary in concentration from 86 picomolar to 19,440 picomolar (1 picomolar is 10‑12 moles/liter).

Several strategies have been used to interrupt quorum signaling (see ref. 2) and it is an approach of considerable interest to better control bacterial effects.


As shown on other pages of this website, BiCARBUS Activated Solution has been shown in laboratories, field tests, and commercial applications, to result in scale disintegration, base oxidant longevity and resultant improvements in microbial exposure and water quality. Often experienced water quality chemists are amazed at these results with such relatively low concentrations of BiCARBUS Activated Solution.

We think these macro effects are best understood by assuming the Activated Solution, created in a proprietary electrochemical reaction from salt water, is affecting the water microbial quorum sensing. This could be done by affecting one or more of the QS steps reviewed above. Concentrations are still significant with respect to quorum sensing signal molecule concentrations.                                                                                       

Ken B. Jensen, Ph.D.