Biobatteries and bioengineered petroleum manufacturing.

17 February 2014

In the twenty-first century you'd be hard pressed to find a piece of every day kit that doesn't have a power cell of some kind running it. Cellphones, tablets, laptops, MP3 players... they all need to be plugged in periodically to recharge. Under optimal conditions they can go two or three days in between top-offs but sometimes that isn't practical. Additionally, rechargable power cells have a finite lifetime and start to run dry faster and faster after two or three hundred recharges. This next bit of tech makes me wonder... a research team at Virginia Tech has figured out how to build fuel cells that replicate certain aspects of metabolism to generate electricity. Called biobatteries, they run on malodextrin (a sugar which is considered an equivalent to dextrose) because nature has shown that it has a fantastic energy density, is relatively stable, and the reactions to liberate the energy from the electron bonds are fairly simple. The Virginia Tech biobattery uses a complement of thirteen synthetic enzymes to liberate 24 electrons from each molecule of malodextrin, which if you do the math works out to a power density of about 0.8 mW/cm^2 and an energy storage density of 596 Ah/kg... that's an order of magnitude greater than the lithium polymer power cells in your cellphone or laptop. Chief reseearcher Y.H. Percival Zhang says that they're about three years away from being able to go into commercial production.

In somewhat related news Audi has cut a deal with Global Bioenergies to continue research into bioengineering bacteria to produce complex hydrocarbons as waste products. The cost of drilling, pumping, and refining oil being what it is today some forward-looking companies have been researching alternative methods of producing the petroleum products necessary for use as fuel. The technique is an older one that has been going slow and steady development and involves genetically engineering E.coli to secrete long-chain fatty acids called bio-isooctanes that can be refined into octanes. Interestingly, some of the spliced genes cause the E.coli cultures to not emit carbon dioxide as a metabolic byproduct, meaning that more of the carbon available to the bacterial cultures goes into making hydrocarbons instead of being lost as gas. Two large scale production facilities are running at this time, and if it proves a feasible technique more may be constructed in the future.