E. coli Takes On Biofuels

by Jessica Velez, Angel Fernando Cisneros Caballero and Narjes Alfuraiji (Science Trends) ... In the genetic engineering world, E. coli is a valuable user-friendly host with a well-known growth metabolism and the largest set of genetic engineering tools available. Many people may be surprised to know that this bacteria has been studied extensively for gene regulation and expression, and has served as a source of valuable substances for human use, such as insulin production for diabetes treatment. Escherichia coli is able to consume various sugars, allowing for versatile growth conditions at both laboratory and industrial scales, making E. coli the organism of choice for genetic engineering.

The advancement of genetic engineering has enabled geneticists to modify genes to produce more or less of a specific potential biofuel, such as isopropanol. These modifications alter the genetic makeup of the organism by introducing a new gene or modifying an existing one. This can be done by changing a DNA base pair (adenine-thymine/guanine-cytosine), deleting a whole gene, or inserting multiple genes. Tools which allow biological engineers to transfer entire metabolic pathways from one organism to another have been developed, allowing scientists to work with more easily engineered organisms in a laboratory. These tools are generally available for use in organisms such as viruses and bacteria, and transferring a gene or sequence of genes into a different organism allows this organism to produce a molecule of interest, such as isopropanol.

Acetone and isopropanol are sustainable, cheap, have high energy densities, and have been tested as alternative fuels. These biofuels are already compatible with existing engines (Poh & Poh, 2017), and isopropanol has a higher blending capability than ethanol with lessened corrosive effects. Just like isopropanol, acetone has a higher energy density and blending capacity in comparison to ethanol and is also less corrosive to engines. All of these traits mean that both isopropanol and acetone have the potential to complement or replace ethanol in the biofuel market, and both of these are naturally produced by a bacterium called Clostridium acetobutylicum.

The ability to transfer an entire metabolic pathway from C. acetobutylicum into E. coli may lead to commercially viable applications of an organism’s natural abilities to produce efficient, high-quality biofuels that can improve or replace traditional fuel, thereby alleviating emerging supply and environmental problems associated with ethanol. Challenges still remain with engine and fuel mixture optimizations to reduce emissions and improve the energy yield, but current results are encouraging in our mission to reduce our dependence on petroleum. READ MORE