Bacteria & Surprising Chemistry

Abstract

I did graduate work with a chemistturned-biologist and that long-ago association still influences my scientific interests. I still tend to gravitate toward biochemistry, and so it's not surprising that, in addition, I gravitate toward microbiology, and bacteria in particular. I think that for interesting chemistry, you just can't beat bacteria. And with so much attention today on the molecular basis of bacterial activities, there is more than enough research being done to satisfy my chemical curiosity. One item I came across recently reports on researchers in California who have found that there are bacterial enzymes that break down the shells of diatoms (Bidle & Azam 1999). Previously, it was assumed that diatom shells were of no nutritional value, that physicalchemical processes alone were responsible for their destruction (Smetacek 1999). But when natural assemblages of marine bacteria were added to diatom colonies, the dissolution of the shells increased dramatically. A similar effect was produced when proteases were added, suggesting that bacterial enzymes attack the protein coating on the shells. These experiments point to an important role for bacteria in the oceanic biogeochemical cycles of silicon and carbon, because diatoms play a significant role in marine ecology.