3.7. Gas chromatographic analysis
Fig. S4 depicts the gas chromatographic (GC) analyses of n-alkane
fraction obtained from the crude oil contaminated liquid culture
sample after 2 weeks of biodegradation. The chromatograms
show that the alkane level is significantly lowered in the petroleum
oil contaminated aqueous sample seeded with USTBa strain. Initially,
n-alkanes in the range of tetradecane to hexatriacontane
were found in the crude oil. After 2 weeks of incubation, there is
a sharp decrease in component abundance of the crude oil
(Fig. S4c), inferring that n-alkanes are significantly reduced by B.
methylotrohicus USTBa in the aqueous culture medium. It is interesting
to note that in the range of 82–100% degradation rate, the
abiotic factor alone could reduce n-alkanes as depicted in Fig. 7.
This was confirmed by the diminution or the total disappearance
of the corresponding peak of each compound compared with that
of the abiotic control. On the other hand, Lal and Khanna [38] reported
58% (C17-C24) overall degradation of Indian crude oil samples
by Acinetobacter calcoaceticus and Alcaligen odorans in
combination over a 15 day period.