At OU-Norman, I will be meeting a microbiology class to talk about biofilms. I know it’s hard to believe how beautiful a biofilm can be, especially when it’s growing on your teeth. But this one pictured above is a marine bacterium Marinobacter hydrocarbonoclasticus SP17 growing on alkanes (hydrocarbon pollutants). It’s not only beautiful, it’s doing us service by cleansing our oceans–and as we all know, our oceans desperately need cleansing.
How do biofilms grow? Surprisingly, there is a pattern common to many biofilms formed from many different species, often multiple species in one biofilm. First the swimming bacteria decide to settle (not sure how; sometimes they communicate with each other by chemical signals called quorum sensing.) Then they stick their flagella onto a substrate, and start to pile up next to each other. The cells grow in a monolayer, and start coating themselves with polysaccharide (long chains of sugars–sticky). In the advanced stage, the biofilm builds up towers of semi-dormant cells with nutrient channels inbetween. Finally, the towers grow buds of motile “planktonic” bacteria that escape to go out and start new biofilms elsewhere.
The process can be deadly, especially if it happens inside your lung when you have cystic fibrosis. But the same Pseudomonas bacteria–in a very different setting–can make a sugar polymer called alginate, a biodegradable material that we can harvest and use for all sorts of things, like dental products and artistic sculptures.
What would you like to do with biofilms?