TPH biodegradation potential of B. subtilis and P. aeruginosa
strains from NE India were far higher than some previously
reported values, even for mixed cultures (Chhatre
et al., 1996; Del’Arco and de Franca, 2001; Obuekwe and
Al-Zarban, 1998; Sugiura et al., 1997) and comparable to
degradation of Nigerian crude-oil by B. subtilis and P. aeruginosa
strains isolated from crude oil-polluted soil from
Nigeria (Ilori and Amund, 2000). From the results on bacterial
assimilation of about 26–22.0% of TPH carbon loss
from growth, it could be concluded that all the TPH lost
from the growth medium should not be considered as assimilated
and same of it must have been catabolized and/or
respired by bacteria. Further, in-contrast to the shake Xask
study, biodegradation experiment in soil was conducted at
37°C temperature to ensure the capability of bacterial strain
under study to degrade the TPH and its various fractions at
an average outdoor temperature of soil in this region.