Bacterial Biodegradation and Bioremediation of Hydrocarbon

Antarctica is one of the largest and most pristine wilderness areas left on
earth. The main human activities in this area are scientific research, tourism
and fishing, and all these activities require fuels for transport and energy.
An important fraction of the petroleum hydrocarbon produced worldwide are
extracted and processed in cold areas (Ruberto et al., 2003). In the Antarctic
continent, although petroleum exploitation is not permitted, the important
scientific and logistic activities represent high risk of pollution in an
environment where temperature and other climate factors, strongly limit
bacterial growth and activity.

Antarctic waters are now crossed regularly in summer by tourist, supply and
fishing vessels. According to Parker and Howard (1977), oil contamination of
soil was also a consequence of the Dry Valley Drilling Project. Three shipping
incidents brought the risk of hydrocarbon pollution of polar water into focus.
The wreck of the oil tanker Exxon Valdev off the Coast of Alaska on 24 March
1989, resulted in the release of large quantities of crude oil. Earlier, in
the Antarctic, the supply ships Nella Dan and Bahia Paraiso ran aground and
subsequently sank off Macquarie Island and near Antarctic Peninsula (Kennicutt
et al., 1991; Karl, 1992; Smith and Simpson, 1995).

Cripps and Priddle (1991) reported that accidental fuel spills on land occur
mainly near scientific stations where storage and refueling of aircraft and
vehicles can result in spills. Petroleum hydrocarbons have been detected in
soil from McMurdo Station, Scott Base, the former Vanda Station and the old
Marble Point camp site within the McMurdo Dry Valley Region, and in soil from
H.Arctowski Polish Station and Palmer Station on the Antarctic Peninsula
(Krzyszowska, 1990; Kennicutt et al., 1992; Tumeo and Wolk, 1994; Aislabie et
al., 1998). Generally the areas contaminated by terrestrial fuel spills are
localized ; however runoff, from soil has contaminated sub-tidal sediments.
These were comparatively minor incidents but significant amounts of diesel fuel
and lubricating oil were released into the sea and washed ashore.

With the increasing attention towards the preservation of the environment, the
applied technologies gained increasing interest. Biodegradation of
hydrocarbon-contaminated soils, which exploits the ability of microorganism to
degrade and/or detoxify organic contamination, has been established as an
efficient, economic, versatile and environmentally sound treatment. At low
temperatures, the viscosity of oil increases, and the volatilization of short
chain alkanes is reduced and thus their water solubility and toxicity is
increased. Long-chain alkanes are more insoluble or exist as solid at low
temperatures, and thus their biodegradation is hindered by their limited
bioavailability (Whyte et al., 1998). Diesel oil is a complex hydrocarbon
combination deriving from the distillation of crude oil having carbon numbers
that range approximately from C9 to C20, such as paraffin, olefins, naphta and
aromatic compounds.

The objectives of this study are:
1. To isolate diesel-degrading bacteria.
2. To identify diesel-degrading bacteria.

Growth optimization of the diesel-degrading bacteria. Site and soil sampling.
Soils were chosen as the samples. Samples were collected from several
diesel-contaminated areas. Jubany Station which was located in Argentinean
Base, King George Island, South Shetlands Islands, Antarctica (61.5 degree S
54.55 degrees W), as well as soils from pristine area near the elephant refuge
(62.15 degrees S, 58.38 degrees W) were selected as the sampling site.
Samples were also collected in Casey Station which is just outside the
Antarctic Circle. Casey Station is on the coast of Wilkes Land, in a area
called the Windmill Islands (66.17 degrees S, 110.32 degrees E).

Four samples at different location were taken at Jubany Station and were
labeled as J2, J3, J4 and J7. Three samples were collected at hill near
elephant refuge and were labeled J1, J5 and J6. Only two samples were
collected at Casey Station and it were labeled as F and G. All samples were
taken during the austral summer of January 2003. Soils were collected 15-20
centimeter (cm) beneath the surface and were placed in sterile screw-capped
vials. The samples were immediately placed in a freezer and stored at -20
degrees C until returned to Universiti Putra Malaysia, Selangor, Malaysia for
further examination.

Through the process J2 , J3 , J7 and G were selected for further experiments.
Pure single bacteria culture from these bacterial consortium were screened
individually J2(p), J3(p), J7(p) and G(k). Identification was carried out
using the BiologTM identification system.

1. J2(p) was identified as Vibrio hollisae with 99.99% probability.
2. J3(p) was identified as Vibrio hollisae with 99.99% probability.
3. J7(p) was identified as Moraxella sp. with 89.56% probability.
4. G(K) was identified as Pseudomonas stutzeri with 92.04% probability.