Geosmin

The quest to understand the smell of soil began in 1891 when Berthelot first investigated the phenomenon, but the compound responsible remained unidentified for another 74 years. In 1965, Gerber and Lechevalier finally isolated geosmin from Streptomyces bacteria and named it using the Greek words geo (earth) and osme (smell). The name captures precisely what this molecule represents: the scent of the earth itself. In 2002, the publication of the Streptomyces coelicolor genome sequence by Sir David Hopwood's team at the John Innes Centre revealed the single bifunctional enzyme responsible for geosmin production. This discovery explained why humans respond so universally to this smell. Research suggests Streptomyces produces geosmin most actively in moist conditions, effectively signaling the presence of water to organisms that can detect it, an evolutionary advantage for the bacteria and the creatures guided by the scent.