On January 7th a study was published about chemists at the University of

California, Davis, who engineered blue-green algae to grow chemical precursors for fuels

and plastics. A chemical precursor is a compound that participates in the chemical

reaction that produces another compound. These scientists have taken a big step in replacing fossil fuels as the raw materials for the chemical industry.

“Most chemical feedstocks come from petroleum and natural gas, and we need

other sources,” said Shota Atsumi, assistant professor of chemistry at UC Davis and lead

author of the study in the Proceedings of the National Academy of Sciences. Feedstocks are raw materials required for an industrial process. These scientists are trying to satisfy the demand for environmentally friendly mixtures of chemicals to feed into the fuel- and plastic-making processes.

The U.S. Department of Energy (DOE) has set a goal of obtaining a quarter of

industrial chemicals from biological processes by 2025. One way of reaching this goal is

through the use of biomass. Biomass is organic matter used as a fuel. The chemical

potential energy in biomass is converted into energy by burning it, fermenting it (turning

it into alcohol), letting it decay or using chemicals to convert it into a gas or liquid.

Biomass is a renewable energy source because trees and crops used for energy can be

regrown. Using biomass as a source of energy is also advantageous because waste is

reduced and U.S. agriculture is supported since crops are used as energy sources.

Wood, landfill gas, and even garbage are sources of biomass. As garbage rots and

decays, methane gas is produced. Recently, trash has been burned to generate electricity.

Methane, the main ingredient in natural gas, is odorless, colorless, and relatively cleanburning

compared to fossil fuels, but it is flammable and there is a possible danger of explosions. Biodiesel and ethanol are other examples of biomass being used as sourcs of energy. Biodiesel is a fuel made from vegetable oils, animal fats or greases. Most biodiesel today is made from soybean oil. Ethanol is an alcohol fuel made by fermenting the natural sugars found in corn, wheat, potato waste, sawdust, urban waste and lawn clippings.

Cyanobacteria, also known as “blue-green algae,” seem to be the best alternative

to fossil fuels so far. They do not compete with food needs, like corn’s role in the creation

of ethanol or biodiesel, and they are not flammable like methane. The only initial energy

input needed is solar energy to create chemical reactions for photosynthesis. The

challenge is getting the cyanobacteria to make larger amounts of chemicals that can be

readily converted to chemical feedstocks. Atsumi’s lab at UC Davis has been working on

introducing new chemical pathways into the cyanobacteria with help from the Japanese

chemical manufacturer, Ashahi Kasei Corp.

The researchers identified enzymes from online databases that carried out the

reactions they were looking for. Then they put the enzymes into the cells. Finally they

built up a three-step pathway that allowed the cyanobacteria to convert carbon dioxide

into 2,3 butanediol, a chemical that could be used to make paint, solvents, plastics and

fuels.

“Because enzymes may work differently in different organisms, it is nearly

impossible to predict how well the pathway will work before testing it in an experiment.

After three weeks growth, the cyanobacteria yielded 2.4 grams of 2,3 butanediol per liter

of growth medium, which was the highest productivity yet achieved for chemicals grown

by cyanobacteria and with potential for commercial development,” Atsumi said, hoping

to continue working on this project and further increase the system’s productivity.

Atsumi wishes to experiment with other products, while corporate partners

increase the technologies’ effectiveness, bringing us closer to reaching the DOE’s target

of replacing 30% of transportation fuels with biofuels by 2030. Our dependence on

foreign oil has reached over 60% of domestic consumption. Displacing 15% of the

projected gasoline usage by 2017 will require a rapid expansion of renewable fuel

production. In addition, gas emissions are negatively impacting the Earth’s climate.

Science-driven innovations in technology will be critical to addressing these detrimental

situations.

To reach the president’s goal of reducing gasoline usage in the U.S. by at least

20% by the year 2017, it is necessary to expand the supply of alternative fuels and

increase the efficiency of transportation and technology. Burning natural gas, coal and oil (including gasoline for automobile engines) raises the level of carbon dioxide in the atmosphere, thus contributing to global warming. Developments such as those with the cyanobacteria will help reduce green-house-gas effects as well as our dependence on foreign oil. Replacing fossil fuels with energy from environmentally friendly bacteria and biomass will reduce the nation’s carbon-emission footprint, and bring energy production to the United States.

Works Cited:

http://utah.agclassroom.org/files/uploads/nie4/food10_11.pdf

http://www.biologynews.net/archives/2013/01/07/engineered_bacteria_make_fuel

_from_sunlight.html

http://genomicscience.energy.gov/pubs/Biofuels_Flyer_2007-2.pdf