Miniscule Maids: How Microbes are Cleaning Up Our Messes

Bacteria have earned a bad reputation. They are the frequent cause of illness, the reason we scrub every surface in our homes, and they send us running for the nearest bottle of hand sanitizer whenever mentioned. However, recently, bacteria have been turning the tables on humans and cleaning up their act, or more accurately, our messes.

Oil, Oil, Everywhere
Ever since the unfortunate occurrence of oil spills began ravaging our waters and shorelines, scientists and environmentalists alike have been trying to determine the best way to bring relief to the affected areas and their inhabitants. Surprisingly, researchers have found that saving the lives of the affected organisms depends on the underlying capabilities of their microscopic comrades. While the idea of bioremediation, the process by which microorganisms, mainly bacteria, degrade chemical substances, has been a topic of study since the 1940s, the technique only became well-known in the 1980s when oil spills became more common. (Photo at left: A duck covered in oil after a spill, http://science.howstuffworks.com/cleaning-oil-spill.htm/printable).

Interestingly, while the ability to degrade oil sounds like an alien skill, many microorganisms are naturally capable of enzymatically breaking down the hydrocarbons present in petroleum. Petroleum degradation is performed by a wide variety of bacterial species, most of which reside in marine environments. Hydrocarbon-degraders are present in low numbers in clean marine environments. However, in petroleum-polluted waters, their populations increase dramatically. Through various internal chemical reactions, petroleum-degrading bacteria are able to process hydrocarbons and produce the non-toxic end products of carbon dioxide and water. Once an oil spill occurs, remediation usually involves stimulating the growth of hydrocarbon-degrading bacteria populations through the addition of nutrients and increased oxygen exposure. Occasionally, bacterial cultures from outside sources are added to the site of the spill to assist with the degradation of the oil.1 Oil-degrading bacteria work hard to help reverse the damaging effects of oil spills.

It’s a Dirty Job, But Somebody’s Got to Do It
Bacteria can also be found hard at work in a very different body of water. The process of sewage treatment relies heavily on the metabolic activity of various types of bacteria to break down the wastes present in the water. A typical wastewater treatment process involves the use of aerobic, oxygen-using, and anaerobic, oxygen-intolerant, bacteria. Following the filtration of the wastewater to separate larger debris, an aerobic phase utilizes oxygen-using bacteria to break down organic material, typically producing carbon dioxide, acids, and what is known as sewage sludge. The sludge is then processed in an anaerobic phase, in which bacteria that cannot tolerate oxygen metabolize the components of the sludge and produce methane gas. As a bonus, this end product can be used as a source of energy for the treatment plant.2 Thus, bacteria are again being used to break down unwanted, potentially toxic substances into relatively harmless end products. (Photo at right: Aerobic digestion at a sewage treatment facility, http://www.aiaaeration.com/gallery/images/DSC00202.JPG).

Recently, researchers have also found other interesting ways in which bacteria can contribute to wastewater clean-up. Certain bacteria possess cell structures known as magnetosomes, which contain the metal magnetite. These structures typically allow bacteria to use the magnetic field of the Earth to navigate. However, these unique organelles can be used to benefit sewage treatment because the magnetite within them allows the bacteria to absorb metals that may be present as contaminants in the treatment water. Upon completion of metal absorption, the bacteria can be removed from the water using a magnet, reducing the excessive use of chemicals.3

Devouring Grocery Bags
Although little is known at this time, researchers are beginning to learn about the existence of bacteria that are capable of degrading plastic, particularly the plastic that comprises grocery bags. Remarkably, the first person to discover these unique bacteria was a 16-year-old Canadian high school student named Daniel Burd. He was able to culture four possible strains that were present during his plastic-degradation experiments. He found that a strain of Sphingomonas has the ability to degrade plastic in culture and a strain of Pseudomonas helps it to reproduce. While the process behind this degradation is not yet understood, the possibility of plastic degradation by bacteria is a promising discovery that could help remedy the problem of plastic build-up in landfills.4 (Photo at left: Plastic bags accumulate in our landfills, http://www.mvrecycling.com/images/bag_pile.jpg).

Do You Want Lactobacillus With That?
Thanks to a recent influx of information, many people are aware of the benefits of probiotics, or substances that assist with the growth of beneficial microbes in the body. Probiotics are most often found in yogurt and the species Bifidobacterium and Lactobacillus are the most commonly studied. The list of benefits resulting from the intake of probiotics is endless. When presented as active-cultures in foods, such as yogurt, probiotics were found to be effective at preventing bacterial diarrhea. Probiotics have been regarded as immune enhancers, inflammation reducers, and effective treatments for enzyme deficiencies, such as lactose intolerance. The inflammation-reducing effects have even been found to benefit the heart. Interestingly, these probiotic bacterial species are also considered to be active inhibitors of cancer, as they have the ability to decrease carcinogens in the intestines.5 From cleaning out toxins to reducing digestive issues, probiotic bacteria are cleaning up the messes we make within our bodies. (Photo at right: Yogurt is only one example of a food that contains probiotics, http://www.elliemay.com/images_blog/2008-01-15-yogurt.jpg).


Sources
1 Bioremediation Methods for Oil Spills, Pace University, 12 October 2008 .
2 Bacteria, Robert E. Marquis, Ph.D., 2008, Microsoft Encarta Online Encylcopedia, 12 October 2008 .
3 Lins et al., “Simple homemade apparatus for harvesting uncultured magnetotactic microorganisms,” Brazilian Journal of Microbiology June 2003, 12 October 2008 < pid="S1517-" script="sci_arttext&tlng=">.
4 Eoin O’Carroll, “Canadian teen discovers plastic-bag devouring microbe,” The Christian Science Monitor May 2008, 12 October 2008 <>.
5 Fast Facts About Yogurt and Beneficial Bacteria, Alan Greene, MD, November 2007, Dr.Greene.com, 12 October 2008 .