How Nature Makes Earth Aroma

October 12 2007

It's been known for more than 100 years that geosmin, a terpene, is responsible for the pleasant scent of moist soil, although it wasn't isolated and structurally characterized until 1965. Now scientists have deciphered how geosmin is made by the soil bacterium Streptomyces coelicolor.

What has surprised researchers is that, instead of 2 or more enzymes catalyzing a series of steps, one enzyme alone catalyzes the conversion. The N-terminal half of the enzyme uses farnesyl diphosphate to crank out germacradienol, which subsequently is handed off to the C-terminal half to complete the transformation into geosmin.

Category: Now You Know
Filed under: Microorganisms