Scientists Engineer Bacteria to Make Gasoline Alternative

This is a pretty standard news story I did on a new scientific finding for my Principles of Journalism class in Spring '10.




In a finding that could have a dramatic impact on the global climate and energy debates, scientists at UCLA have found a way to turn carbon dioxide into fuel through the use of genetically modified bacteria, researchers announced Thursday.

The process produces the chemical isobutanol, which has been proposed as an alternative to gasoline, and in fact is already being used as a gasoline additive. The researchers say the bacterial reaction that produces the fuel is energy-efficient because it is powered by photosynthesis, so sunlight is the only external energy needed to drive the reaction.

“This is potentially much more efficient and less expensive than the current approach,” said James C. Liao, associate director of the UCLA–Department of Energy Institute for Genomics and Proteomics and leader of the research team. “This new approach avoids the need for biomass deconstruction…which is a major economic barrier for biofuel production.”

In an article published in the latest edition of Nature Biotechnology, researchers from the UCLA Henry Samueli School of Engineering and Applied Science describe how they modified the cyanobacterium Synechoccus elongatus to ingest carbon dioxide and, with the help of sunlight, produce isobutyraldehyde gas, which can then be converted into liquid isobutanol.

Biofuels have been identified as one potential alternative to harmful carbon emission-producing fossil fuels, which have been blamed for the steady rise in atmospheric carbon dioxide thought to contribute greatly to global warming. Since many algae use light to digest carbon dioxide, scientists have studied the use of these organisms to convert CO2 into valuable products such as fuel. However, the conversion of algae into biodiesels requires many intermediate steps, adding to production costs.

Cyanobacteria also can be used to make hydrogen, another potential energy source, but this is still a rather inefficient method, according to scientists. Yet another approach is using genetically modified bacteria to convert CO2 and water into ethanol, but ethanol has significant drawbacks as a potential alternative fuel. It must be mixed with gasoline because it cannot power a vehicle on its own, and can be corrosive unless it undergoes costly modifications.

These attempts have highlighted the two main criteria necessary for a commercially viable biofuel: the conversion of CO2 and extraction of the fuel must both be cost- and energy-efficient. The UCLA research team say that the cyanobacteria they engineered readily converts carbon dioxide into isobutyraldehyde, which is advantageous because it is easy to extract, purify, and convert into several petroleum-based chemicals, including the viable gasoline alternative isobutanol.

Isobutanol is among a group of so-called higher-chain alcohols, which make fuels that are more efficient than ethanol while also being less corrosive and volatile. Though they have not fully refined their process yet, the researchers write that “the productivities of the engineered cyanobacteria for isobutyraldehyde and isobutanol …are already higher than the productivities of cyanobacteria demonstrated for hydrogen or ethanol.”

The discovery of an efficient, environmentally-friendly gasoline alternative is particularly relevant as leaders from 193 countries converge on Copenhangen this month for the United Nations Climate Change Conference in an attempt to establish a global climate agreement. Delegates hope to establish global guidelines and regulations to continue and extend the provisions of the Kyoto Protocol, which expires in 2012. Biofuels are playing a prominent role in the conference; organizers have chartered limousines that run on biofuels made from plant waste to carry delegates to events, and emphasis on the transportation industry and its need to reduce emissions is expected to be greater than in previous climate summits.

However, biofuels have seen a backlash in the face of reports that their production from crops such as corn cuts into farmland and, subsequently, the food supply. In 2007, the European Environmental Agency Scientific Committee called for further study of the environmental risks of biofuel production, citing accelerated deforestation and concerns about sustainability. This led the EU to backtrack on its goal for biofuels to make up 10% of all transportation fuels in Europe by the year 2020.

Recently, second-generation biofuels that use biomass such as plant waste and bacteria have come back in favor. Less than a week before Liao and his team released their findings, the U.S. Department of Energy announced a $564 million investment in advanced biorefinery projects.

“Advanced biofuels are critical to building a cleaner, more sustainable transportation system in the U.S.” said Energy Secretary Steven Chu. “These projects will help establish a domestic industry that will create jobs here at home and open new markets across rural America.”

Though the production of isobutanol with cyanobacteria is still in the early stage, the UCLA team is optimistic. “This result demonstrates the technical feasibility for direct conversion of CO2 to fuels or chemicals, which could become an economically feasible option after further improvement,” they write. “The strategy…may provide an alternative path for addressing two of humanity's most pressing problems: energy and climate change.”