11.3 Diversity of Microbial Volatiles
The available literature and databases allow estimating the known structural
diversity of volatiles derived from plantflowers ca. 1,700 volatiles from 991 species
(Dunkel et al. 2009 ), 1,093 volatiles from 491 microbes, including 135 fungi and
356 bacteria (Lemfack et al. 2014 ). Yet considering that 2,98,000 of plant species
(Mora et al. 2011 ), 10
7
- 10
9
bacterial species (Schloss and Handelsman 2004 ), and
1.5 million fungal species (Hawksworth 2001 ) might exist on earth, the number of
volatiles will be added more to databases as new species are being characterized
and discovered. The 1,093 volatilome from the MVOC database (Lemfack et al.
2014 ) grouped into 13 chemical classes (Table11.1).
11.4 Microbial Volatile Organic Compound (MVOCs)
Collection and Detection
For bioprospecting the microbial volatile compound, the first and foremost
requirement is their detection in the source, identification and afterwards their
collection. However, analysis of these volatile compounds poses challenges as they
tend to occur in mixtures, possess different chemical properties, and are generally
Table 11.1 Per cent contribution of major and minor group of microbial volatiles (Lemfack et al.
2014 )
% contribution of
volatileTotal diversityMajor group of volatile
Terpenes 11 Major groups of volatile compound representing
Ketones 13 64% of total diversity
Organic acid 10
Alcohol 16
Aromatic
compounds14Minor groups of volatile
Alkanes 5 Minor groups of volatile compound constitute 36%
Alkenes 3 of total diversity
Nitrogen
compound5Sulfur
compound7Aldehydes 7
Esters 7
Furans 2
Ethers <111 Harnessing Endophytic Microbial Volatile Organic Compound... 241