| Established biofilms may consist of microbial cells, exopolysaccharides, an extracellular protein, and extracellular DNA (eDNA). The structure and components of exopolysaccharides, eDNA as well as extracellular protein vary from one bacterium to another. Biofilm formation for each bacterium may be formed regulated by different genetic and environmental factors including the medium, matrix properties, temperature, pH, nutrient availability as well as the presence of organic material. During biofilm formation, bacteria are able to perform cell-to-cell signaling known as quorum sensing activity. In the quorum sensing process, bacteria communicate with one another. Bacterial cells may communicate with each other via quorum sensing activity, which in turn supports the attachment process as well as detachment. QS regulates several processes in some bacteria including pathogenicity, transfer of DNA, production of some secondary metabolites, bioluminescence, sporulation, conjugation, motility, competence, antibiotic production, as well as biofilm formation in response to signaling molecules of quorum-sensing systems. A cell-to-cell communication mechanism known as quorum sensing (QS) has been found to play a role in P. aeruginosa biofilm formation, because both QS and biofilms are impacted by the surrounding environment. QS plays a role in biofilm development as well as biofilm maintenance. In this system, bacteria use signaling molecules. Several Gram-negative bacteria use N-acyl-homoserine lactones (AHLs) as a signal molecule for cell population density. Whereas Gram-positive bacteria use autoinducing peptide (AIP) as their autoinducers. Quorum sensing enables bacteria to communicate with each other at intraspecies and interspecies levels by influencing the gene expression of several genes as well as the behavior of the entire community, although the chemical signals and quorum sensing system differ. |