Biofilms allow microbes to live close to one another, participate in genetic exchange, and take advantage of a nutrient rich area. They provide protection against predators, toxins, and are resistant to many antimicrobial chemicals and antibiotics that the cell alone are not.
Cells have the ability of quorum sensing, which allow them to sense the presence of others and communicate with one another. Through quorum sensing they can stop producing flagella, make more polysaccharide, and increase the efficiency of nutrient transportation.
Common locations of biofilms are teeth, intestines, rocks, soil, plants, medical implants, and pipes used for things like oil and water.
Here I have depicted cells using flagella to swim. Here they have come together and using their multitude of sticky fimbria they are able to adhere to a surface and produce a polysaccharide biofilm. I have also depicted sells using their pili to exchange genetic information. The holes in the biofilm are water channels which allow for water and nutrients to flow through increasing the amount of nutrients that is able to be taken in.
Some common bacteria that produce biofilms are Streptococcus sanguinis with the oral cavity, Neisseria gonorrhoeae, Salmonella typhinurium.