Geosmin compound characteristics

Geosmin and Methylisobomeol in Drinking Water 531 Table 4.7 Geosmin and MIB compound characteristics. 

Geosmin, 2-Methyl isobomeol (MIB) and 2-isopropyl methoxy pyrazine are known to be produced by various types of actinomycete cultures (10-15). Geosmin and MIB are saturated tertiary alcohols and resist oxidation. The steric configuration of the hydroxyl and methyl groups in both compounds are believed to interact with receptors in the nose, imparting their characteristic earthy odour (16). The four compounds itemised as the key osmogenes in this odorous emission have extremely low odour threshold concentrations. Their occasional occurence in drinking water can lead to widespread complaints and are routinely monitored for within this Authority. 

The characteristic odour of raw, wet land is caused by the presence of two terpenoids, monoterpenic alcohol (-)-2-methylisobomeol (8-22) and the sesquiterpenoid (-)-geosmin (8-23) produced by streptomycetes, myxobacteria and cyanobacteria. Both compounds cause an unpleasant odour in drinking water and some foods, such as canned mushrooms, wheat, coffee and meat of freshwater fish... 

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