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Bacteria Biotech in Oil Industry

Because of the ability of bacteria to break down a variety of compounds into their basic elements, bacteria are used extensively in environmental biotechnology. One of the applications where bacteria are gaining greater use is in the oil industry.

Bacteria can easily move compounds in and out of their cells. This makes them perfect processing units. After death, all organisms decompose to their base elements: water, carbon, nitrogen, phosphate, and trace elements. This process is called biodegradation or ineralization, and is carried out by bacteria.

Several different types of bacteria are capable of breaking down both simple and complex hydrocarbons (organic compounds that contain only hydrogen and carbon), the components of crude oil. Two of the major families in which these microbes are found are Pseudomonas and Bacillus.

These bacteria are described as oleophilic. So they are attracted to oil. They use hydrocarbons as a food source, or simply break hydrocarbons down, with no obvious use for them. The bacteria convert the hydrocarbons into methanol (a type of alcohol), water and carbon dioxide.

Pseudomonas and Bacillus are commonly found in areas that naturally contain oil, such as near underground oil deposits. However, these bacteria can also be found where there is no oil. This is because the ability to break down hydrocarbons is not always the bacteria’s main function, so these traits may lie dormant.These bacteria can live in a range of habitats. Though most live under conditions considered normal for microbes, there are also some new specimens that have been dubbed extremeophiles.

An extremeophile is an organism that is capable of, and often prefers, living in environments that until recently were considered uninhabitable or intolerable to any life form. For example, bacteria and other microorganisms have been found in various types of rock several hundred metres (and in some cases, kilometres) below the Earth’s surface.

The oil industry is using hardy oil-eating bacteria in a number of ways. The most common applications are in bioremediation (using microbes to clean up pollutants) of oil spills or reduction of the environmental impact of waste products from oil production.

Oil Industry Application
Image of Biofilm ReactorWater is used to help remove oil from the ground or refine it into petroleum products. As a result, waste water containing dissolved hydrocarbons makes up the largest volume of waste material generated by the oil and gas industry. For example, a typical refinery uses about 18 barrels of water for every barrel of crude oil it processes. Some of the components of dissolved hydrocarbons, such as phenols, are highly toxic and do not break down in the environment. If the waste water is to be recycled or released as surface water, it must be treated to remove virtually all of the dissolved oil.

One way this can be done is through the use of bioremediation lagoons, where water is placed in a large pond-like enclosure and treated with oil-eating bacteria. Because this process tends to be slow, expensive and inefficient, Saskatchewan researchers began looking for ways of using bacteria that would quickly and efficiently clean waste water.

The water is pumped into the top of the reactor tube. Gravity pulls it down through the bacteria-covered packing material. At the same time, air is pumped in from the bottom in order to keep the bacteria growing and digesting.

Tests show that using the biofilm reactor, or bioreactor, is a very efficient way of enabling the bacteria to do their work. Both types of bacteria tested were able to remove the hydrocarbons from the waste water in far less time than it takes to treat the water in a lagoon. As well, the reactor bacteria did a very thorough job.

The researchers also tested the biofilm reactor on salty water contaminated with hydrocarbons. This is the kind of waste water that comes from oilfields. The tests showed the reactor is able to handle this type of water. The researchers’ success with the biofilm reactor means this system could become one of the chief methods of cleaning both oilfield and refinery waste water. By adjusting the size of the reactor, and the type of bacteria used, the system can be modified to meet the specific water treatment needs of each sector of the oil and gas industry.

The SRC plans to test the biofilm reactor in a pilot plant. Eventually, scientists would like to see this bioreactor become the water treatment workhorse of the oil industry. A future issue of Infosource will examine other uses for bacteria in the oil industry.

A chemical engineer at the University of Saskatchewan, Dr. Gordon Hill, demonstrated that a special process which utilizes a strain of Pseudomonas can cost-effectively remove contaminants from oil industry waste water. This process has been further tested by the Saskatchewan Research Council (SRC), using the Pseudomonas strain and another type of oileating bacteria currently found in bioremediation lagoons. In this process, waste water is pumped through what is called a biofilm reactor. This reactor is essentially a large tube filled with packing material, through which water can percolate. The material is covered with a thick film of bacteria.

To establish the biofilm, scientists grow the bacteria in the reactor tube. They feed the bacteria a diet of hydrocarbon components and other nutrients. Air is gently bubbled through the tube, so the bacteria can grow and “digest” the hydrocarbon wastes. Once the bacteria have multiplied sufficiently to create a thick film in the tube, researchers can use the tube to treat waste water.

Reference: www.agwest.sk.ca