Science in Review

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The World’s dependence on fossil fuels is evermore in highlight. Oil prices have reached high-price records hitting the $90 mark during this week and developed countries are screaming for alternative fuel sources to be developed (at least those who do not profit from oil).

One approach was to turn to corn as a base for ethanol production. This led to a skyrocketing of corn prices with many producers looking to sell their grain to ethanol producing industries which, of course, decreased the amounts of available grain for food production. So, it seems that the solution is also not in corn. After all, the available land for corn production is also limited in the world.

Recently, I came across a research abstract from P. Fu and J. Dexter from the University of Hawaii, submitted to the AIChE 2007 Spring National Meeting at Huston that really spiked my curiosity and could, if well developed, come up with a feasible answer to ethanol production to be used as fuel, without the disadvantage of depleting food supplies.

From that abstract:

We have developed an integrative biological and engineering approach to construct novel cyanobacterium Synechocystis strains for direct conversion of sunlight and CO2 into ethanol. We have successfully transformed the pyruvate decarboxylase (pdc) and alcohol dehydrogenase II (adh) genes from Zymomonas mobilis into Synechocystis sp. PCC 6803. Our preliminary studies have confirmed that it is feasible to create such ethanol producers from cyanobacterial systems. We are continuing our effort to optimize our ethanol production approach so that it may topple the global dependence on fossil fuels. It is found that the photosynthetic cyanobacteria can be redesigned for highly efficient ethanol production by the combination of gene transformation, strain/process development and metabolic modeling/ profiling analysis. Our goal is to create a sound and sustainable method to reduce the cost of ethanol production to the point that the ethanol production is competitive to utilization of fossil fuels.

What does this all mean?

Cyanobacteria obtain their energy through photosynthesis. Meaning, cyanobacteria are capable of using sunlight to reduce carbon (and nitrogen) and convert carbon sources like carbon dioxide to other forms, using water as the electron donor.

The cyanobacteria used in this study, the Synechocystis, was the third prokaryote and first photosynthetic organism to have its genome sequenced, turning it into a much studied model organism. So, by tweaking around with it’s genome (by inserting two genes from Zymomonas mobilis), the authors managed to produce a strain that is capable of using gaseous carbon dioxide, water and sunlight to produce ethanol.

Limitations

Removing carbon dioxide directly from the atmosphere and producing a fuel source in the process seems quite the dream for our planet’s environmental problems. But not everything is that bright.

The prototype showcased by Fu and colleagues can only produce about 5 grams of ethanol per day (about 134 kilojoules of energy) which is nothing. Although they envision having a major ethanol producing plant using this system is 2-3 years, the process is still very limited. Actually, I have no idea if the power needed to maintain such plants would not exceed the output. But let’s assume it’s viable. Sounds like a good approach.

Possible solutions

Although the first steps are given (and assuming that no major oil corporation tries to cover everything up) much research is still needed to turn this project into something that can be deemed as feasible. So, ethanol is coming out. What next?

Probably we’ll see cooperation with experts in bioinformatics and protein engineering to further tweak the structures of the main player proteins in the process. Some enzymes have been “upgraded” this way in the past creating little machines that outperform their native counterparts by several orders of magnitude. If a strain can be developed that truly increases the output of ethanol (and thus use of carbon dioxide) then a major milestone will be put in place for alternative energy sources. As is, I still have my doubts. Let the research begin.

Related on this blog:

• Science Linked: Bacteria - The Results
• Science Linked: BACTERIA
• Salt Water as fuel? A closer reality