Thursday, May 15, 2008

What the floc?

ResearchBlogging.orgIf you ever deal with wastewater, you'll notice that there are small bits of particulate matter floating in it. I'm not going to go into the gory details of what a portion of that matter is because I think your imagination can do a pretty good job of figuring it out on its own.

However, a substantial portion of this matter is bacterial in nature. Some bacteria are free-floating, in that they don't adhere to other bacteria and exist in the environment independently. Others aren't so happy doing things that way, and they form films and flocculants to keep their communities together.

One such example is Comamonas badia. He's the little guy with the "tail" (referred to as a flagellum) on the left. The manuscript cited in this post characterizes this organism, specifically the strain IAM 14839, which was isolated from activated sludge in Japan. Activated sludge is the biological material found in wastewater treatment facilities. It's biomass, and is used in the treatment of raw sewage.

This paper is fairly straightforward. They isolated the organism from a floc and did some basic biochemical studies. First, they Gram-stained it, and demonstrated it is Gram-negative. It was catalase and oxidase positive.

The authors then did fatty acid analysis, which is one way to "fingerprint" bacteria. They also did 16S analysis, which is another way to "fingerprint" bacteria, and this placed the organism in with the genus Comamonas. However, this is the only known strain of Comamonas which can form floc (we've recently isolated similar strains in our laboratory).

So, what?

There may be practical purposes for wanting to use floc-forming Comamonas strains in wastewater treatment. For example, Nitrosomonas species do not like growing in a free-floating (planktonic) form. They would much rather grow adhered to something, anything. This is why Nitrosomonas cultures are typically grown on fine sand or some other surface. It might be possible to use floc-forming Comamonas strains as a platform for culturing specific Nitrosomonas strains for use in wastewater treatment.

BTW: If you're curious as to what a flocculant culture looks like, here is one to the left. This is a culture which does contain both Nitrosomonas and Comamonas. How the two interact with each other is not currently known, but we're in the process of figuring that out.

Tago, Y., Yokota, A. (2004). Comamonas badia sp. nov., a floc-forming bacterium isolated from activated sludge. Journal of General and Applied Microbiology, 50(5), 243-248. Click here for PDF of article.

No comments: