Properties of Oil
E. Elements in a Bacterial Cell
Properties of Oil
Oil is a term applied to liquid
fats derived from
various sources including plant seeds, animal fats, and mineral
deposits. Petroleum, also known as crude oil, is naturally found
in sedimentary rock. It is made of hydrocarbons, which are
organic compounds of hydrogen and carbon. Sulfur and oxygen are
also found in petroleum, but it is usually a smaller amount, from 0.1
to 5%. These molecules can be divided into three classes:
aliphatics, alicyclics, and aromatics. Aliphatics have carbon
atoms arranged in long, open chains; alicyclics have circles of carbon;
and aromatics have six carbons arranged in a ring, bonded three times.
Scientists have been able to see the toxicity of oil
by its effect on marine life. Crude oil is very dangerous, not
only to marine ecosystems, but to humans too. While humans can
digest vegetable oil, they cannot break down crude and motor
oil. According to the National Ocean Service, oil spills
can have serious
long-term impacts to the environment.
“The long-term impacts to birds and mammals include
lower reproduction rates and physical mutations in offspring. Harmful
oil components can contaminate fish that are in turn eaten by other
fish, seabirds, and humans, thus passing these harmful components up
the food chain. Once oil is trapped in sediments, it can be
recirculated into the water and remain in the food chain for many
years. Some research indicates that oil can remain in sediments for
hundreds of years.” (NOAA/NOS)
Spilled oil is extremely difficult to clean up. It spreads
rapidly, and with a
fast current and wind can form a slick within minutes. After
spreading, the lighter parts of the oil immediately begin
benefits of this, however, are often offset by wave action, which mixes
the water into the oil to form a heavy and sticky water-in-oil
emulsion, called “chocolate mousse”. The mousse can form in as
little as ten to twenty hours after a spill. It is important,
therefore, that rescue workers arrive at an oil spill quickly.
In addition to a short response time, a successful
clean up operation requires equipment, such as skimmers and pumps,
which can handle emulsified oil and debris or dispersants, manpower,
and a place to dispose of the oil. No major oil spill has ever
had such essential equipment on site in a short time frame.
Without them, unfortunately, the oil spreads, eventually becoming as
thin as paint, even more difficult to clean up than the thick,
sticky mousse. Return to top.
Bioremediation is the process of using living
micro-organisms to clean up a contaminated site. Micro-organisms
do this by removing toxins from materials. They decompose these
compounds by using enzymes, specific proteins that control reactions in
living cells. Organisms that produce enzymes capable of degrading
petroleum are useful in cleaning up oil spills. Some common ones
that break down oil are pseudomonas, flavobacterium, arthrobacter, and
azotobacter. Bioremediation accounts for 5 to 10 percent of all
pollution treatment and has been used successfully in cleaning up
leaking underground gasoline storage tanks. Other toxic
substances that have been successfully bioremediated include the
solvent toluene, the moth repellent naphthalene (mothballs), the
herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), and the fungicide and
wood preservative pentachlorophenol.
Bioremediation has many applications, from the
ordinary garden compost to the removal of selenium and other toxic
metals from waste. The best agents for bioremediation are the
ones that can break down contaminants without becoming contaminated or
There are several advantages to
bioremediation. One is minimal cleanup. The adverse
reactions on the environment seem to be
minimal. “Also, bioremedial agents often accomplish their work in
site, meaning that they act directly within the contaminated site,
thereby avoiding the need for costly physical removal and cleanup of
wastes.” (Smith: 200). The Exxon Valdez was the first major
oil spill which bioremediation was used on a wide scale. Return to top.
Biostimulation is the process of adding nutrients to
help oil-eating bacteria grow and reproduce faster, but it does not
work in all conditions. While temperature, pH, oxygen, and ocean
salinity are only four of the factors that can affect a successful
biostimulation process, overall, it has been used successfully.
“In summary, laboratory studies have shown that biostimulation…can
enhance the rates of oil biodegradation, particularly in marine
environments.” (Zhu et al: 8). One of the first places
biostimulation was used on a large scale was on the shoreline after the
Exxon Valdez disaster.
In spite of the fact that biostimulation on the open
sea is difficult because of tides, it ha advantages. It is
inexpensive and environmentally friendly. On the other hand, it
takes time for the
treatment to work, making it unpractical for oil spills that require
immediate cleanup. Another issue is that adding nutrients can
result in undesirable side effects such as algae blooms. Return to top.
Some of the types of bacteria that can degrade
hydrocarbons are achromobacter, bacillus, flavobacterium, and
pseudomonas. These bacteria belong to the Kingdom Monera and are
heterotrophic, eating carbon as their major food source. In an
untouched environment, they make up less than 0.1% of the bacterial
Bacteria are prokaryotic cells, which means they
membrane-bounded nucleus. They are smaller than most eukaryotic
(cells containing a membrane-bounded nucleus) cells. Most range
in size from 0.2 to 3.0 micrometers. They exist in three basic
shapes: spherical, rod-shaped, and spiral shaped. Bacteria can be
aerobic, meaning needing oxygen; anaerobic, meaning oxygen is deadly;
or facultative anaerobes, which means they can use oxygen or survive
Many of the bacteria capable of degrading oil are
Gram negative and rod-shaped. These include Pseudomonas,
Acinetobacter, Flavobacterium, Corynebacterium, and Alcaligenes.
Pseudomonas exist in the Phylum Pseudomonads. They are straight,
or slightly curved rod-shaped, motile by one or several flagella, and
aerobic. They reproduce asexually, and in an ideal environment,
can divide every twenty minutes.
Usually their growth is shown in four stages: Lag
Phase, Log Phase, Stationary Phase, and Death Phase. The
Lag Phase is when bacteria acclimate to a new environment. Once
they are acclimated, the Log Phase begins. This is when they
begin multiplying logarithmically. The Stationary Phase is when
the bacteria begin competing for a limited supply of food. The
Death Phase takes place when lack of food and increased toxic waste
causes them to die. Return to top.
E. Elements in a
A bacterial cell is made up of 50% carbon, 20%
oxygen, 14% nitrogen; 8% hydrogen, 3% phosphorus; 1% potassium; 1%
sulfur; 0.2% iron, and 0.5% each of calcium and magnesium.
(VanDemark, Batzing: 134). In addition, bacteria require other
nutrients, such as sodium, zinc, manganese, molybdenum, copper, nickel,
tungsten, selenium, and cobalt. (Brock et al: 119).
•Principal source of cellular materials.
• Pseudomonas can use over 100 different molecules as
carbon sources, including
proteins, fats, carbohydrates, and
•Found in carbon dioxide and organic compounds.
•Together with oxygen, essential to all
aspects of cell life.
• Used in cellular water and material.
• Found in organic compounds, H2, and H2O
• Main ingredient in cellular water and material.
• Important for aerobic respiration.
• Found in H2O, organic compounds, CO2, and O2.
• Major ingredient in proteins and nucleic
• Present in the cell wall.
• Found in decay of dead organisms. Inorganic
forms are ammonia or nitrate.
Most bacteria can use ammonia as their sole
nitrogen source. Not all can use nitrate.
• Important to energy metabolism.
• Used in nucleic acids and phospholipids.
• Found as phosphate salts.
• Used in amino acids, such as cysteine, and
• Found from inorganic sources, such as sulfate or
• Activates enzymes used in protein synthesis.
• Stabilizes ribosomes.
• Used in formation of cell walls.
• Buffers electrical charges within a cell.
• Stabilizes cell walls.
• Important for respiration.
• Found in many cellular proteins.
Includes such elements as:
Requirement based on
the location of the species.
Zinc: Important in
enzymes, such as carbonic anhydrase, alcohol dehydrogenase,
RNA, and DNA
Important for some metabolic
in formation of Vitamin B12.
Important for enzyme activity.
Important to enzymes involved in