methanethiosulphonate, 4-octanone, and 1-phenylpropan-1-one produced by
Burkholderia ambifaria.The mycelial growth ofFusarium culmorum,F. oxyspo-
rum,Colletotrichm gloesporioides,andSclerotum rolffsiwas significantly inhibited
byfifteenBurkholderia tropicastrains (Groenhagen et al. 2013 ).
11.6 Endophytic Microbial Volatiles as Promising Source
of Next Generation Biofuel Production
Recently, a number of endophytic bacteria and fungi have been discovered that
make hydrocarbons while utilizing cellulosic polymers found in plant-based agri-
cultural wastes. The action of different hydrolytic enzymes converts the agricultural
waste substrate into volatile compounds that are either identical to or are closely
linked to those specific categories of molecules that are found in diesel such as
mono-terpenoids, alkanes, cyclohexanes, cyclopentanes, and alkyl alcohols,
ketones, benzenes, and polyaromatic hydrocarbons. For example, thePhomopsis
sp. produces VOCs such as sabinene, pinene, 3-methyl-1-butanol, 1-propanol,
2-methyl and 2-propanone, and benzeneethanol that are being explored as the
components for the next generation aircraft fuel (Grigoriev et al. 2011 ; Strobel et al.
2011 ). Similarly,Ascocoryne sarcoides,Ascocoryne cylichium,andAscocoryne
solitariaproduced a broad range of volatiles including alkanes, alkenes, alcohols,
ester, ketones, acids, benzene derivatives, terpenes, and esquiterpenes. Majority of
these VOCs are similar to diesel because of their cyclic and branched structure
(Rude and Schirmer 2009 ; Griffin et al. 2010 ; Mallette et al. 2014 ).
An endophyte,Nodulisporiumsp. was isolated fromMyroxylon balsamumpro-
duced VOCs with fuel potential. Under microaerophilic growth environments, the
organism produced 1,8-cineole, propylcyclohexane, acetone, 2-pentanone,
3-hexanone, 4-methyl and 5-hepten, 2-one, 4-methyl, 3-hexanone, -methyl-1-butanol,
1,4-cyclohexadiene, 2,4-dimethyl, 1-4 pentadiene and cyclohexene, 2-hexanone,
1-methyl-, 1-methyl-4-(1-methylethenyl)-, along with some alcohols and terpenoids of
interest as potential fuels. In an aerated large fermentor,Nodulisporiumsp produced a
number of products such as 3-methyl-1-butanol, 2-methyl-1-propanol, 1-pentanol,
1-hexanol, 1-heptanol, 1-octanol, benzene derivatives, alkyl alcohols, ketones, esters, a
few terpenoids, 1-nonanol along with phenylethyl alcohol as ingredient of diesel
(Mends et al. 2012 ). The 1,8-cineole, 1-methyl-1,4-cyclohexadiene, and (+)-
amethylene-a-fenchocamphorone also have the potential to be used as a fuel additive,
produced byHypoxylonsp. (CI-4A) (Tomsheck et al. 2010 ). In addition to alkanes
and long-chain hydrocarbon, many fungal species produce other potential biofuel
targets, such as ethylene, ethane, propane, and propylene (Ladygina et al. 2006 ).
However, little information is available about the bacterial volatiles as fuel
potential as compared to traditional bioethanol and plant oil-derived biodiesel. The
identified relevant volatile compounds include various short-to-medium chain
alkanes, alkenes, alcohols, and isoprenoids, which hold large potential to substitute
246 D. Chandra et al.