Solid inoculants as a practice for bioaugmentation to enhance
bioremediation of hydrocarbon contaminated areas
Abstract
Vacuum freeze-drying is a scientifically advanced method to prepare
solid inoculants from oil degrading bacterium. The introduction of
oil‒degrading microbes or bioaugmentation can be an efficient way to
bioremediate oil spills in marine areas, where oil-degrading bacteria
are deficient. The purpose of this study is to evaluate the potential
use of solid inoculants of LZ-2 bacteria to enhance the degradation rate
of crude oil. In this study, response surface methodology (RSM) was
incorporated into the experimental design to optimize a response, which
is influenced by different protectants. Our results showed that five
factors have interactive and synergistic protective effects on the
growth of LZ-2. Optimal growth of freeze-dried LZ-2 (63.8%) was
observed with a 10.5% solution of skim milk supplemented with 14.3%
sucrose, 14.4% of trehalose, 4.9% of glycerin and 14.7% of
β-cyclodextrin. The culture grew in medium containing crude oil (3 g/L)
at 37 °C at 150 rpm for 30 days, GC and GC-MS analysis showed
biodegradation of 44.2 and 21.6% for total saturate and aromatic
hydrocarbons respectively. These results indicated that the solid
inoculants of LZ-2 bacteria had the potential to be used for ex-situ
bioremediation of hydrocarbon pollutants associated with crude oil.