Applied Microbiology

Environmental Applications

Microorganisms are being considered as solutions to environmental issues facing the planet, including pollution cleanup, clean energy, and natural resource recovery.
Microbes are used to help solve environmental issues through bioremediation. Bioremediation is the use of microorganisms to remove or detoxify pollutants. For example, the dilemma of how to clean up environmental oil spills has led to the discovery of oil-consuming bacteria. Such bacteria were immensely helpful in the cleanup of BP's 2010 oil spill in the Gulf of Mexico. Species included the order Oceanospirillales, the genus Colwellia, the family Methylococcaceae, and the genus Alcanivorax. Alcanivorax borkumensis is a gram-negative oil-degrading bacterium that lives near the surface in the ocean and is barely detectable in normal conditions. After an oil spill, its numbers increase exponentially. A. borkumensis generates a biofilm to help emulsify, or break up the oil into small droplets, so that bacteria can utilize the oil.

Bacteria in Bioremediation

The bacterium Alcanivorax borkumensis consumes oil and can be used in the bioremediation (use of microorganisms to clean up) of oil spills.
Plastic waste is a major source of pollution due to the length of the lifespan of plastic in the environment. In 2016, a team of scientists from Japan led by Shosuke Yoshida, described a bacterium capable of breaking down the plastic found in many bottles into a carbon food source. This bacterium, Ideonella sakaiensis, produces a specific enzyme capable of cleaving chemical bonds in the large plastic polymers, or substances with a molecular structure made up of many similar units bonded together, to break them into smaller carbohydrates.

Algae are being explored to make biofuel that could replace fossil fuel usage. Scientists have seen that a polyculture, a diverse mix of algal species, produces more biocrude fuel from less biomass investment. Biomass is the total number of organisms in an area, and biocrude is a synthetic fuel that may serve as a substitute for petroleum.

Microbes can also be used to mine metals from ore. Some bacteria, such as Thiobacillus ferrooxidans, take up metal ions as part of their metabolic processes. These bacteria oxidize the metals and convert them to forms that dissolve in water. These metals are then available for collection by humans. This process is called leaching and is often used to extract metal that would otherwise be unavailable.
Thiobacillus ferrooxidans, a type of bacterium that takes up metals during its metabolic processes, can be used to extract metals from water in a process known as leaching.
Credit: Dopson et al.License: CC BY 4.0
Some researchers believe that by the middle of the 21st century, microbes may be the main source of pollution remediation, fuel production, and natural resource mining. Further, plant and tree leaves and leaf-associated microbes may be used to mitigate pollutants in the air, a process called phylloremediation.