Metabolism

metabolism

Solving human problems by letting bacteria do what they are already the greatest masters of, metabolizing. This section groups EPFL’s research projects that use existing remarkable properties of microbial metabolism to degrade human waste, precipitate toxic compounds and create cement. Now we just need to find one bacteria for every man made problem and humanity is saved!

Bioremediation – metabolizing waste

Bioremediation is a technique that uses microorganism to clean waste produced by us humans. It is based on the natural ability of microorganisms to metabolize a wide range of compounds. While metabolizing, microoganisms break down the compound, turning it into harmless, natural substances.
 
At EPFL, several project use the remarkable properties of microorganisms to clean water and soils.

 

Bioremediation of organic pollutants in soils and aquifers

The main objective of this research is to develop treatment technologies to remediate soils and aquifers polluted with different organic pollutants where the metabolic activity of bacteria as well as plants and their rhizosphere is used. Fundamental aspects such as characterization of the microorganisms and microbial communities involved, their molecular biology, biochemistry and physiology, as well as applied aspects such as the design of monitoring tools are investigated.

Research Lab: prof. Christof Holliger, Laboratory for Environmental Biotechnology

 

Metal Bioremediation: Uranium, Arsenic, Selenium
Toxic metals are difficult to remove because they cannot be degraded like organic compounds. However, depending on the chemical form of the metal, its toxicity can vary greatly.  
We use bacterial metabolism to transform toxic metals, such as uranium, selenium and arsenic into less toxic forms. More specifically, this entails forming solid phases from the soluble metals and thus, making the metals less bioavailable. Microorganisms indigenous to most soils and aquatic ecosystems can carry out this transformation when provided with the right substances. The metals turn into minerals that no longer pose a threat to water quality.

Research Lab: Rizlan Bernier-Latmani, Environmental Microbiology Laboratory

 

Bio-improved Soils

Biologically induced calcite mineralization has been recently brought into focus as an alternative cementation mechanism for soils. The whole process lies on the metabolic activity of unicellular microorganisms that are responsible for generating those conditions that allow for the formulation of calcium carbonate crystals to take place. The technique has its base at two chemical reactions; the hydrolysis of urea catalyzed by the enzyme urease, produced by the bacteria strain Sporosarcina pasteurii, and the calcite precipitation. This knowledge is put to use in an emerging grouting technique called microbial induced calcite precipitation (MICP). By temporarily regulating the concentration of bacteria and chemical constituents in a soil, a new engineering material can be generated through the nucleation of calcite crystals inside the soil matrix. Understanding and controlling this alternative environmentally friendly soil reinforcement technique, exposes innovative applications, such as restoration of weak foundations, seismic retrofitting, erosion protection, seepage flow or pollution mitigation and construction of floating beaches.

Watch Dimitrios Terzis explain his PhD Thesis on this subject in a fun and simple way.

Research Lab: prof. Lyesse Laloui, Laboratory of Soil Mechanics,