Effect of Temperature on Bioremediation



Effect of Temperature on Bioremediation

Microbiology

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Khusbu Patel

2501 West Addison Street

Lane Tech College Prep High School

Chicago, IL 60618

Grade 10

Table of Contents

Acknowledgements………………………………………………………………………………..5

Purpose…………………………………………………………………………………………….6

Hypothesis…………………………………………………………………………………………6

Review of Literature………………………………………………………………………………7

Materials...…………………………………………………………………………………….…18

Procedure…………..………………………………………………………………………….…19

Results……………………………………………………………………………………………20

Conclusion……………………………………………………………………………………….25

Reference List……………………………………………………………………………………27

Acknowledgments

I would like to thank my chemistry teacher, Mr. Kopack, for ordering my materials. I would also like to thank Dr. Lang for assisting me in my procedure and answering any questions that I had about my experiment. I would also like to take this time to express my gratitude to Mrs. Mikbel for proofreading and revising my entire paper, along with helping me understand how to write an effective science paper. Mr. McAdam was one of the other teachers that helped me create graphs and tables for the data that was collected during my experiment. In addition, I would like to extend my appreciation to my dad for buying some of the supplies necessary for this experiment.

Purpose

The purpose of this experiment was to compare the amount of motor oil that is biodegraded by Escherichia coli in different temperatures and to figure out if temperature affects the biodegradation of motor oil.

Hypothesis

If motor oil and Escherichia coli are placed in 2 different temperatures, then the motor oil placed in 37oC, the highest temperature, will have degraded the most because warmer temperatures allow bacteria to grow, while colder temperatures freeze bacteria so that they do not grow or work properly, causing less oil to be degraded.

Review of Literature

Scientists have been using microbiology, the study of unicellular and multi-cellular microscopic organisms, for many years now. The study of microbiology includes learning about fungi and protists, also known as eukaryotes, and prokaryotes, which are organisms that do not include a cell nucleus in their cells (Boyd, 1988). Also, viruses and prions are not classified as living organisms, but they are still studied under the subject of microbiology (1988). Generally, microbiology is the study of life that cannot be seen by the naked eye. The study of microbes has helped the world in so many ways. Scientists have found information about illnesses and cures for certain diseases. They also know how the human body works and how organisms affect humans in various ways. In addition, microbiology has helped the environment in ways that would not have been found if experts did not do research or experiments on theories and other beliefs.

One area of research in microbiology deals with oil pollution, one of the most harmful types of pollution on earth. It has also become an enormous problem in the world. Not only does it harm humans, but oil can also hurt other types of animals as well. Birds, for example, can be killed just by getting oil into their feathers, and as a result of this, the animals cannot stay warm, so they freeze to death. In addition, the damage oil pollution causes is extremely hard to repair and only certain procedures can help reduce oil pollution; one of them is using bacteria to degrade the oil. The study of microbiology has helped scientists figure out that microorganisms can remove human waste products from the environment. Different temperatures in the environment, though, can cause different results to occur (Owens, 2004).This experiment is testing if different temperatures can change the effect of microorganisms helping the environment by getting rid of small amounts of oil, and, according to the research, it is highly likely that microbes will be able to degrade oil in room temperature and in warmer climates, then in colder temperatures.

Oil Spills

General effects of oil spills. All around the world, oil is being transported for human use. Throughout this procedure, accidents usually happen which cause oil spills to occur. These spills may sound like any normal, minor spill, but they are actually one of the most harmful types of pollution caused by humans. Oil pollution has become a big problem ever since men started to transport oil from one place to another (B. Delille, D. Delille, & Pelletier, 2002, p. 118-119). Industrial activities, which include oil and gasoline exploration and transportation, contain toxic waste, which is released into the environment because of the spills and accidents (Van der Meer, 2006, pp. 36-37). Oil spills can occur on land and even in the water. Oil is a hazardous chemical used by humans for fuels, plastics, dyes, and many other substances. This substance is extremely sticky and can damage the environment easily. Animals of all sorts, like birds, mammals, and fish, can be killed just by ingesting oil. Others can be killed instantly from consuming a prey that has been contaminated with oil (National Wildlife Federation, 1997, p. 57).

Cleaning up oil spills. Since oil is toxic, it is extremely difficult to clean up. Experts use protective clothing and advanced equipment to protect them from coming into close contact with the oil (1997). People have also started to become prepared for oil spills to occur by training workers, improving technology, and plotting out marshes and endangered species’ habitats (1997). This allows them to be ready for an oil spill when it happens. In addition, people have tried to prevent oil spills by using safer navigation and screening a ship’s safety record to make sure less and less oil spills occur each year (1997, p.88-89).

Even though oil is a harmful substance, it does not mean it cannot be cleaned up. Oil-degrading microorganisms can help clean up an oil spill. They first open up their genes that are required for degradation (Van der Meer, 2006, p. 36-37). They can also increase their number in size to the amount of carbon exposed (2006). After this, the microorganisms will take in the oil, like they take in nutrients (2006, pp. 36-37). Another way for experts to quicken the process of cleaning up is by adding fertilizer and oil decomposers to the oil spill (Fujita et al., 2003, pp. 442-443). Also, there are three different types of chemicals that can speed up the process of clean oil spills: nutrients, cleaners, and dispersants (Nyman, 1999, para. 6). Nutrients can be added to the oil spill to quicken the process of degradation of oil. Cleaners can be used to help clean oil because they wash away the oil from surfaces back into the water, thus keeping land clean and healthy (1999). Dispersants can be used because they help break the oil into smaller particles, or droplets, allowing it to become easier to dilute the oil (1999). No response to oil spills is also another option because the oil will eventually evaporate and degrade into wetlands, where the soil is saturated with moisture (1999).

Bioremediation

Bioremediation is the removal or transformation of contaminants from the environment by organisms (Litchfield, 2005). In other words, bioremediation of infected or polluted environments is a way to restore the earth’s surface (Abraham et al., 2003, pp. 162). This method has been going on for as long as humans had to degrade waste (Litchfield, 2005). Of course, bioremediation is being used more often right now because better technology has been developed. For instance, when oil is being transported from place to place, oil treatment agents, like fertilizers, dispersants, and oil decomposers, are developed for oil spill bioremediation (2005). For example, during the most recent oil spill, the Exxon Valdez, the method of bioremediation was used to clean up the oil from the sea (Fujita et al., 2003, p. 442-443).

In addition, many tests and experiments have occurred to understand how bioremediation works. For example, on June 8, 1990, the Norwegian tanker, Mega Borg, was carrying crude oil about 57 miles off the Texas coast (Lee et al., 1996). All of a sudden, an explosion and fire occurred, spilling approximately 45 m3 of Angolan Palanca crude oil into the ocean (1996). For experimental purposes, a trial was conducted a day after the accident to test the bioremediation of the oil. During the experiment, little of the oil was cleared up, but not much (1996). There have been several other oil spill incidents where bioremediation products have been used in an attempt to improve oil biodegradation. In general, though, it is difficult to draw valid conclusions from many of these efforts because of the time constraints in planning experiments with the appropriate controls after a major spill. Another type of field study was taken in February 1996, and it is proved that, during the experiment, microbial response and activity was high and rapid showing that the rate of degradation improves when bioremediation agents are present (Delille, et al., 2002, p. 118-119).

Over the past few years, more and more people have become interested in developing a cost-effective technique for bioremediation (2002, p. 118-119). Terry Hazen, the head of the ecology department at the Lawrence Berkeley National Laboratory in California even said, “Bioremediation holds great promise for some of our worst problems” (Voigt, 2010). Even though, after many different trials, it is still proven that there is little convincing evidence to suggest that bioremediation is effective, bioremediation does help remove waste in some way, thus making the earth a better place to live in (Lee et al., 1996).

Microorganisms

Wide-ranging microbes. Microorganisms, the simplest organisms in life, are able to degrade any human waste products, including oil spills, making the earth a safer and cleaner place to live in (Van der Meer, 2006, p. 35-36). All around the earth, millions and millions of microorganisms exist. Even with that, though, scientists still believe that less than one percent of all microorganisms have been identified (Voigt, 2010). Microbes represent about 50 to 90 percent of all life in the ocean (2010). In 1981, the very first microorganism to be patented was a strain of the bacteria, Pseudomonas, which was found to degrade oil of four species in only one (2010). The world’s oceans also contain microscopic life. There have been magnificent discoveries of previously unknown microorganisms, most of which made a significant impact on the earth (Arrieta et al., 2006, p. 12115-12116).

Bioremediation. The method microorganisms use to help and improve the environment is called bioremediation. They detoxify and degrade the environmental contaminants, making them safer and less perilous (Delille, et al., 2002, p. 118-126). When microorganisms are introduced to waste products, they learn to adapt to the pollutants and then they start the degradation process (2002).

Microorganisms are crucial for an ecosystem to function. They are helpful in so many ways. For instance, they purify water, soil, and even air (Van der Meer, 2006, p. 35-36). People rely on microorganisms to destroy waste products from industrial, agricultural, and human domestic activities (2006). During this process, microorganisms convert these wastes into carbon dioxide, water, and other biomasses (Litchfield, 2005, p. 273-279). Microorganisms can also produce hydrogen from biodegration, and they can also make metals become less toxic (2005). For example, microorganisms have been found to reduce choromium to the less hazardous type of choromium, creating the use of metals that are safer and environmentally friendly (2005).

They are able to degrade objects that are considered waste to humans, decreasing the amount of pollution in the world. As Terry Hazen, the head of the ecology department at the Lawrence Berkeley National, says, “There is no compound, man-made or natural, that microorganisms cannot degrade” (Voigt, 2010). Furthermore, microorganisms can complete different tasks depending on the type of microorganism, making them all unique.

Escherichia Coli

Discovery. One of the most common bacterium known to man is Escherichia coli. Theodor Escherichia first described it in 1885, and this “Gram-negative, rod-shaped bacterium” was called Bacterium coli commune which was later changed to Escherichia coli, named after its founder (Todar, 2008). For many years this microorganism was considered to be an organism found in part of the large intestine. It was not until 1935, though, that a strain of Escherichia coli was shown to be the cause of an outbreak of diarrhea among infants (2008). Escherichia coli was found in all sorts of food, and whenever people handled infants infected with Escherichia coli, they too obtained the bacterium causing it to spread rapidly (2008).

Uses of E.coli. In addition, Escherichia coli is the head of the large bacterial family Enterobacteriaceae; the enteric bacteria are anaerobic Gram-negative rods that live in the intestinal part of animals in health and disease (2008). The Enterobacteriaceae is one of the most important bacteria medically because the bacteria in the family cause most of the leading causes of death (2008). Escherichia coli are mostly harmless, but some strains can cause food poisoning and other serious injuries. The dangerous thing about harmful Escherichia coli is that, once it is established, an Escherichia coli strain may continue on for months or years (2008). If a strain of Escherichia coli is hazardous, then it may be in one’s body for a long period of time, before leaving, risking one’s life even more than if it was in one’s body for a short amount of time.

Escherichia coli can also respond to environmental signals such as chemicals, pH, temperature, and many more, in a number of very remarkable ways because it is classified as a unicellular organism (2008). For example, it can sense the presence or absence of chemicals and gases in its environment and swim toward or away from them, or it can stop swimming and grow fimbriae which will specifically attach the chemical to a cell, or surface receptor, which are also known as protein molecules (2008).

Overall, Escherichia coli are a well-known microorganism and the uses of this bacterium are beneficial, as well as treacherous. This organism is easily grown and does not necessarily need to stay inside the body because scientists have discovered that it is able to survive outside the body for brief periods of time. Having said this, Escherichia coli can be found basically anywhere including soil, water, food, and many more places (2008).

Temperature

Bioremediation. Temperature plays a key role in environmental problems, including bioremediation. Margesin and Schinner (1997) said, “Most tests and experiments conducted by scientists are carried out at temperatures higher than what is usually found in nature.” In general, though, oil pollution is usually more extreme and serious in lower temperatures (1997). This shows that there are more oil spills in lower temperatures where not a lot of bioremediation takes place. According to Margesin and Schinner (1997), temperatures between 4oC and 30oC have an insignificant number of microbial activities present during bioremediation.

For obtaining best results in bioremediation, higher temperatures and nutrients have to be present (Braddock, Walworth, & Woodlard, 2001). These two factors also have to be properly managed because extremely high temperatures can become harmful to some microorganisms, lowering their bioremediation of oil (2001). This explains that many small factors in nature can cause a huge impact on the environment, even something as little as changes in temperature.

Microorganisms. Microorganisms have been known to live in many extreme environments including places where no photosynthesis occurs or where hot volcano lava is present (Nguyen, 2006). In these different environments, microorganisms are able to adapt and evolve over time so that they are able to live in extreme temperatures (2006). Warmer temperatures cause many microorganisms grow faster and move more quickly. Colder temperatures do the opposite, causing the bacteria to be in a slow-moving state (2006).

Escherichia coli. E.coli, as stated before is usually found on contaminated surfaces, like food, water, and soil. Temperature can also affect how E.coli responds to an environment. A study was conducted showing that E.coli grows best in room temperature rather than colder and hotter climates (2006). E.coli is able to adapt to extreme temperatures, but this can take some time to occur (2006). For example, if the temperature is very hot, E.coli is able to increase its thermal optimum so that it can live in hotter climates. Colder temperatures, on the other hand, usually freeze E.coli without killing the microorganisms. This causes E.coli to respond and move slower than usual, which can lead to less biodegration of oil (2006).

Related Studies

Many related studies were done over the past years about bioremediation and the effect of microorganisms on oil. For instance, a study took place in February 1996 in a remote, sandy beach where scientists were studying the long-term effects of bioremediation agents on biodegradation rate and the toxicity of oil (Delille et al., 2002). Ten experimental trials were taken, and each trial received light Arabian crude oil and some even had bioremediation agents added to them (2002). For example, one had fertilizer added, while another trial had fish composts added (2002). This experiment went on for about three years, and during this time, not many differences occurred, but high microbial populations were present during the experiment (2002, pp. 118).

Another experiment about the biodegration of oil was done when many studies related to bioremediation were tested to find the rate of biodegration of crude oil in seawater (Goldman et al., 1993). These labs were done in a laboratory with and without nutrients and in a field with and without nutrients (1993). In the results, data proved that if the oil concentration goes up, the biodegration rate increases too (1993).

Another study took place after the Nakhodka oil spill accident in January 1997, when microbial population changes were monitored immediately (Fujita et al., 2003). After the experiment, it was concluded that oil-degrading activities in natural environments are regulated by water temperature, dissolved oxygen, nutrient and salt concentrations, and much more (2003). It was also proven that inorganic nutrients like ammonium, nitrate, and phosphate quicken the process of oil spills’ cleanups (2003).

In 1997, a study was conducted where temperature was tested on oil biodegration by yeast in soil (Margesin & Schinner, 1997). It was found that temperature affects the rates of microbial activities because of the physical nature and composition of oil itself (1997). The results of this experiment show that with a higher incubation time and with increasing temperatures, the microorganism quantity present in the experiment also increased (1997). This shows that with warmer temperatures, more microorganisms were present, causing the biodegration to occur faster and more quickly.

At the University of North Wales, a study took place where microorganisms were added to marine water with temperatures of 4oC and 14oC (Andrews, Gibbs, & Pugh, 1975). These waters had a huge amount of nitrogen and phosphorous added. After the experiment, it was found that the amount of nitrogen and phosphorous had not reduced greatly because of the cold temperatures (1975). This experiment shows how colder temperatures cause microorganisms to degrade wastes a lot slower than in normal, room temperature.

Conclusion

Microbiology is an important subject to study, and it has helped technology improve tremendously. Scientists know a plethora of ways microorganisms work after years and years of investigating, researching, and experimenting. This research has also helped to demonstrate that microorganisms can be used for environmental issues around the world and affect humans in both positive and negative ways. For example, microbes can help cure and find illnesses for disease, but they can also be detrimental, causing minor sicknesses, like diarrhea, and even major illnesses, which later can cause death. Also, microorganisms can help the environment by removing unwanted wastes made by humans. As stated before, this research shows that microorganisms can eliminate oil and other hazardous substances from the environment more quickly in warmer temperatures than in colder temperatures. Looking at the whole picture, the study of microorganisms will continue to improve the world because knowledge is unlimited, and scientists will continue figuring out more and more information about the world of microbes and their reactions and effects to different temperatures.

Materials

▪ permanent marker

▪ label tape

▪ 8 culture tubes with caps

▪ 3 pipettes (with graduation marks)

▪ 16 mL of nutrient broth

▪ 120 mm, in height, of motor oil (Castrol Oil 5W-30)

▪ 8 mL of microbial suspension (E.coli)

▪ 16 mL of 0.2% tetrazolium

▪ ruler that measures in mm

▪ incubator (37oC)

▪ refrigerator (13.7oC)

▪ thermometer

▪ camera (optional)

Procedure

1. The 8 culture tubes were numbered 1, 2, 3, 4, 5, 6, 7, and 8.

2. A clean, plastic pipette was used to add 4 mL of nutrient broth to tubes 2, 4, 6, and 8. The pipette was discarded when finished.

3. A ruler was used to add 15 mm, in height, of oil (Castrol Oil 5W-30) to all 8 tubes, using another pipette.

4. A clean, plastic pipette was used to add 2 mL of microbial suspension (E.coli) to tubes 1, 2, 5, and 6. The pipette was discarded when finished.

5. A clean, plastic pipette was used to add 4 mL of 0.2% tetrazolium to tubes 1, 3, 5, and the pipette was discarded when finished.

6. The caps of the culture tubes were placed on firmly.

7. The culture tubes were shook in a slow, stirring motion.

8. The height of the oil was measured in all 8 culture tubes at the initial time period (0 hours) and the solution was observed inside the tube.

9. Tubes 1, 2, 3, and 4 were placed in the incubator (37oC).

10. Tubes 5, 6, 7, and 8 were placed in the refrigerator (13.7oC)

11. For 192 hours, the culture tubes were observed on what was happening inside and how the oil looked. The height of the oil was measured inside each tube every 24 hours, as well.

12. Pictures were taken, if necessary.

13. Steps 1-12 are repeated for a multiple of trials.

Results

Table 2.1

|The Effect of Temperature on Bioremediation |

| | |Time (h) |

| |

|Time (h) |

|Time (h) |0 |24 |48 |72 |96 |120 |144 |168 |192 |

|Trial 1 (mm) |15.0 |15.0 |14.0 |14.0 |14.0 |14.0 |14.0 |14.0 |14.0 |

|Trial 2 (mm) |15.0 |15.0 |15.0 |15.0 |15.0 |15.0 |14.0 |14.0 |13.0 |

|Trial 3 (mm) |15.0 |15.0 |14.0 |14.0 |14.0 |14.0 |14.0 |14.0 |14.0 |

|Mean |15.0 |15.0 |14.3 |14.3 |14.3 |14.3 |14.0 |14.0 |13.7 |

|Standard Deviation |0.0 |0.0 |0.6 |0.6 |0.6 |0.6 |0.0 |0.0 |0.6 |

|Standard Error |0.0 |0.0 |0.3 |0.3 |0.3 |0.3 |0.0 |0.0 |0.3 |

Table 2.3 shows the height of motor oil, in mm, after 192 hours for three trials, and it also displays the mean, standard deviation, and standard error of the three trials for the test tube that includes E.coli and motor oil and was placed in the refrigerator.

|Bioremediation in the Refrigerator (13.7oC) – Tetrazolium and Oil |

|Time (h) |0 |24 |48 |72 |96 |120 |144 |168 |192 |

|Trial 1 (mm) |15.0 |15.0 |15.0 |15.0 |15.0 |15.0 |14.0 |14.0 |14.0 |

|Trial 2 (mm) |15.0 |15.0 |15.0 |15.0 |15.0 |14.0 |14.0 |14.0 |13.0 |

|Trial 3 (mm) |15.0 |15.0 |15.0 |14.0 |14.0 |14.0 |13.0 |13.0 |13.0 |

|Mean |15.0 |15.0 |15.0 |14.7 |14.7 |14.3 |13.7 |13.7 |13.3 |

|Standard Deviation |0.0 |0.0 |0.0 |0.6 |0.6 |0.6 |0.6 |0.6 |0.6 |

|Standard Error |0.0 |0.0 |0.0 |0.3 |0.3 |0.3 |0.3 |0.3 |0.3 |

Table 2.4

Table 2.4 shows the height of motor oil, in mm, after 192 hours for three trials, and it also displays the mean, standard deviation, and standard error of the three trials for the test tube that contains tetrazolium and motor oil and was placed in the refrigerator.

Table 2.5

|Bioremediation in the Refrigerator (13.7oC) – Oil |

|Time (h) |0 |24 |48 |72 |96 |120 |144 |168 |192 |

|Trial 1 (mm) |15.0 |15.0 |15.0 |15.0 |14.0 |14.0 |13.0 |13.0 |13.0 |

|Trial 2 (mm) |15.0 |14.0 |14.0 |13.0 |13.0 |13.0 |13.0 |13.0 |13.0 |

|Trial 3 (mm) |15.0 |15.0 |15.0 |15.0 |14.0 |14.0 |14.0 |14.0 |14.0 |

|Mean |15.0 |14.7 |14.7 |14.3 |13.7 |13.7 |13.3 |13.3 |13.3 |

|Standard Deviation |0.0 |0.6 |0.6 |1.2 |0.6 |0.6 |0.6 |0.6 |0.6 |

|Standard Error |0.0 |0.3 |0.3 |0.7 |0.3 |0.3 |0.3 |0.3 |0.3 |

Table 2.5 shows the height of motor oil, in mm, after 192 hours for three trials, and it also displays the mean, standard deviation, and standard error of the three trials for the test tube that contains only motor oil and was placed in the refrigerator.

Table 2.6

|Bioremediation in the Incubator (37oC) – Oil, E.coli, and Tetrazolium |

|Time (h) |0 |24 |48 |72 |96 |120 |144 |168 |192 |

|Trial 1 (mm) |15.0 |14.0 |13.0 |13.0 |13.0 |12.0 |11.0 |9.0 |8.0 |

|Trial 2 (mm) |15.0 |13.0 |13.0 |13.0 |13.0 |12.0 |12.0 |12.0 |11.0 |

|Trial 3 (mm) |15.0 |13.0 |13.0 |13.0 |11.0 |10.0 |10.0 |10.0 |9.0 |

|Mean |15.0 |13.3 |13.0 |13.0 |12.3 |11.3 |11.0 |10.3 |9.3 |

|Standard Deviation |0.0 |0.6 |0.0 |0.0 |1.2 |1.2 |1.0 |1.5 |1.5 |

|Standard Error |0.0 |0.3 |0.0 |0.0 |0.7 |0.7 |0.6 |0.9 |0.9 |

Table 2.6 shows the height of motor oil, in mm, after 192 hours for three trials, and it also displays the mean, standard deviation, and standard error of the three trials for the test tube that contains motor oil, E.coli, and tetrazolium and was placed in the incubator.

Table 2.7

|Bioremediation in the Incubator (37oC) – E.coli and Oil |

|Time (h) |0 |24 |48 |72 |96 |120 |144 |168 |192 |

|Trial 1 (mm) |15.0 |14.0 |13.0 |13.0 |13.0 |13.0 |13.0 |12.0 |11.0 |

|Trial 2 (mm) |15.0 |15.0 |15.0 |14.0 |13.0 |13.0 |13.0 |12.0 |11.0 |

|Trial 3 (mm) |15.0 |14.0 |14.0 |14.0 |13.0 |13.0 |13.0 |13.0 |11.0 |

|Mean |15.0 |14.3 |14.0 |13.7 |13.0 |13.0 |13.0 |12.3 |11.0 |

|Standard Deviation |0.0 |0.6 |1.0 |0.6 |0.0 |0.0 |0.0 |0.6 |0.0 |

|Standard Error |0.0 |0.3 |0.6 |0.3 |0.0 |0.0 |0.0 |0.3 |0.0 |

Table 2.7 shows the height of motor oil, in mm, after 192 hours for three trials, and it also displays the mean, standard deviation, and standard error of the three trials for the test tube that contains motor oil and E.coli and was placed in the incubator.

Table 2.8

|Bioremediation in the Incubator (37oC) – Tetrazolium and Oil |

|Time (h) |0 |24 |48 |72 |96 |120 |144 |168 |192 |

|Trial 1 (mm) |15.0 |15.0 |14.0 |14.0 |14.0 |13.0 |13.0 |12.0 |12.0 |

|Trial 2 (mm) |15.0 |15.0 |14.0 |14.0 |14.0 |14.0 |13.0 |13.0 |13.0 |

|Trial 3 (mm) |15.0 |14.0 |14.0 |14.0 |14.0 |14.0 |13.0 |13.0 |13.0 |

|Mean |15.0 |14.7 |14.0 |14.0 |14.0 |13.7 |13.0 |12.7 |12.7 |

|Standard Deviation |0.0 |0.6 |0.0 |0.0 |0.0 |0.6 |0.0 |0.6 |0.6 |

|Standard Error |0.0 |0.3 |0.0 |0.0 |0.0 |0.3 |0.0 |0.3 |0.3 |

Table 2.8 shows the height of motor oil, in mm, after 192 hours for three trials, and it also displays the mean, standard deviation, and standard error of the three trials for the test tube that contains motor oil and tetrazolium and was placed in the incubator.

Table 2.9

|Bioremediation in the Incubator (37oC) – Oil |

|Time (h) |0 |24 |48 |72 |96 |120 |144 |168 |192 |

|Trial 1 (mm) |15.0 |15.0 |15.0 |15.0 |15.0 |14.0 |14.0 |13.0 |13.0 |

|Trial 2 (mm) |15.0 |15.0 |15.0 |15.0 |15.0 |15.0 |13.0 |13.0 |13.0 |

|Trial 3 (mm) |15.0 |15.0 |15.0 |15.0 |15.0 |15.0 |14.0 |13.0 |13.0 |

|Mean |15.0 |15.0 |15.0 |15.0 |15.0 |14.7 |13.7 |13.0 |13.0 |

|Standard Deviation |0.0 |0.0 |0.0 |0.0 |0.0 |0.6 |0.6 |0.0 |0.0 |

|Standard Error |0.0 |0.0 |0.0 |0.0 |0.0 |0.3 |0.3 |0.0 |0.0 |

Table 2.9 shows the height of motor oil, in mm, after 192 hours for three trials, and it also displays the mean, standard deviation, and standard error of the three trials for the test tube that contains motor oil and was placed in the incubator.

Figure 2.1

Figure 2.1 illustrates the mean height of oil, in mm, in different temperatures, for all eight test tubes.

Figure 2.2

[pic]

Figure 2.2 displays the mean amount of oil in the four test tubes that were placed in the refrigerator at 13.7oC.

Figure 2.3

[pic]

Figure 2.3 displays the mean amount of oil in the four test tubes that were placed in the incubator at 37oC.

Results Summary

Table 2.1 shows the mean, standard deviation, and standard error for all 8 test tubes, while Tables 2.2-2.9 individually show the mean, standard deviation, and standard error for each test tube. These tables also display all three trials. Figure 2.1 displays all 8 test tubes, showing the mean of all three trials. Four test tubes were tested in the refrigerator and the other four test tubes were placed in the incubator. In addition, two test tubes in the refrigerator included E.coli and another two test tubes in the incubator contained E.coli. Figure 2.1 also displays the error bars for this experiment showing the confidence in these results. Figure 2.2 shows the mean amount of oil for the four test tubes that were placed in the refrigerator, while Figure 2.3 illustrates the mean amount of oil for the four test tubes placed in the incubator.

Conclusion

The hypothesis that the amount of oil would decrease more if Escherichia coli were added to the oil in room temperature was supported by the results in this experiment. In Figure 2.1, it is shown that the oil in the test tube with bacteria, tetrazolium, and oil, that was placed in the incubator had decreased the most amount of oil. According to Table 2.6, the oil in this test tube decreased from 15 mm to 9.3 mm, on average. Also, the test tube with E.coli and oil that was placed in the incubator, decreased from 15 mm to 11 mm. The two test tubes that were placed in a temperature of 13.7oC and included microbial solution decreased a lot less than the test tubes that were placed in the incubator. According to Figure 2.1, all four test tubes that were placed in the incubator decreased and degraded more oil than the test tubes that were placed in the refrigerator. This shows that even without microbial suspension, warmer temperatures degrade oil a lot faster than colder temperatures. Figure 2.1 also shows, though, that the two test tubes that included microbial suspension degraded a lot more oil than the test tubes without E.coli added.

Even though the hypothesis was supported by the data collected, some error did take place. The standard error, though, was between 0.0-1.0, showing that not a lot of error had taken place in this experiment. In Figure 2.1, the error bars, which represent the overall distribution of the data, were overlapping, thus illustrating that the data point could have landed on any part of the error bar. Taking this into consideration, this experiment contained many types of errors that could have occurred. One reason for this error could be the fact that the instrument used was not accurate enough to measure the amount of solution that was placed into the test tubes. For example, using a pipet may not be exact because some liquid could have fallen out when it was being transferred to the test tube, or the precise amount of liquid was not put into the test tubes. For instance, instead of adding 2 mL of tetrazolium, only 1.8 mL of tetrazolium could have been added. Another possible conclusion for having error during the experiment could have been that when measuring the height of the oil in each test tube the only instruments used were the human eye and a ruler that did not go further than measuring millimeters, so the measurement in the experiment may not have been as accurate. Furthermore, every 24 hours, the height of the oil was measured, but during one trial the test tubes were lifted up and the height was measured, which created more error during the experiment. When the test tubes were lifted up and the height of the oil was measured, the oil was not at the exact level, so one part was higher than the other, creating another error. Some of the test tubes, though, did not have big error bars and they were very small, showing that not a lot of error took place. Overall though, the experiment did not have really large error bars, but some error did take place.

This project is a replica of what happens around the world every day. Oil is usually dumped into the ocean by oil spills that are made by humans, and, as this continues, the land and oceans on earth start becoming hazardous and harmful to animals. Sometimes, though, bacteria are able to take in and degrade the oil, helping the environment little by little. Some parts of the

warmer temperatures. This experiment shows how E.coli can degrade oil in warm and cold temperatures, but are there other bacteria that do the same? In the future, different types of bacteria could be used to test if they all degrade oil just like E.coli. Another way of expanding this project could be adding other substances that degrade oil, like dispersants, and fertilizer, to figure out which substance degrades oil the most or the quickest. Right now, though, it can be said that E.coli is able to take in oil faster in warmer temperatures, rather than in colder temperatures, helping everything and everyone in general.

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