Space, the Biobased Frontier: Hot biotechnologies for the Big Beyond

October 21, 2013 |

enterprise-smNext-gen biofuels technologies may be key to making the International Space Station cost effective — not to mention, other destinations in the NASA agenda.

Which may explain why a high-tech algae outfit, Evodos, is advertising on a Star Trek wallpaper site.

Whether your attention is drawn to hot algae techs like Evodos, or elsewhere in the the biofuelscape, cool microbes are producing ordinary materials like electricity, clean water and fuel that are practically priceless in orbit — and from waste materials available to space engineers.

One recently ignited area of interest? For a long, long time, it’s been known that a select group of microorganisms, when provided the right partying conditions, produce electricity as they metabolize.

Over time, a group of researchers, taking advantage of those X-Men like microbial powers, have developed what is generally known as a Microbial Fuel Cell. For example, Orianna Bretschger’s lab at the J. Craig Venter Institute has been at work on this.

Fuel cells: a brief primer

You might remember fuel cells from the space program. Fuel cells combine hydrogen and oxygen to make drinking water and electricity. It was the loss of that technology that drove much of the drama in Apollo 13. In a microbial fuel cell, the electrogenic bacteria are added to a supply of wastewater and, as it breaks down the organic matter, it produces electrons, which are shuttled across the cell membrane and captured at an anode.

It’s a technology under investigation as a source of electricity production (for example, low-power needs in remote areas where battery replacement is not feasible), and there has been quite a bit of research done as a means of cleaning up wastewater. As far as producing useful levels of electricity, as a renewable energy source – well, the electric flow has been relatively slight, and the technology expensive. But a group at Oregon State found a couple of years ago that you could increase the electricity production by a factor of 20 by coating the graphite anodes with a nanolayer of gold.

With new concepts — reduced anode-cathode spacing, evolved microbes and new separator materials — the technology can now produce more than two kilowatts per cubic meter of liquid reactor volume.  Another system, in a prototype form, was developed by a team at the University of Queensland, in cooperation with Foster’s Brewing (yes, same company of “that’s Australian for beer” fame) to work within a brewery setting to convert brewery wastewater to CO2, electricity and clean water.

So, there’s much reason to follow this R&D stream closely. But it gets more interesting.

Gunning the microbial engine to produce hydrogen

To back up a bit, researchers have also known for a long time that, if you give the system a little extra burst of electric power, the microbes can produce hydrogen gas. And the world surely needs an affordable, renewable source of hydrogen. Something that researchers also noticed with a solar cell technology called a photoelectrochemical cell.

(Note for expert readers: the problem lies in overcoming the thermodynamic energy barrier for proton reduction into hydrogen gas.)

The limitation was that the added burst of electricity proved to be costly and complex, using either technology, in scaled-up systems.

But earlier this month, a research team led by Yat Li at the University of California, Santa Cruz, developed a hybrid solar-microbial device and reported their results in a paper published in the American Chemical Society journal ACS Nano. The hybrid combines a microbial fuel cell and a photoelectrochemical cell.

In this case, the electric boost needed to make hydrogen is provided by the microbial fuel cell’s power-generating capabilities. The power is fed to the solar cell, giving it enough energy to split water into hydrogen and oxygen. Ultimately, the only inputs are wastewater and sunlight.

Right now, they are at lab-scale. Next step is t 40-liter prototype, followed by a scale-uop test with a unit installed at a wastewater plant.

The grand synthesis

So, let’s consider where this kind of technology could go. For sure, enthusiasts of reneable power and the hydrogen economy will be interested in the basic power and hydrogen outputs.

Here in Digestville, we are intrigued to think of a bridging technology that could create a synergy between co-located power plants and (or ethanol plants), steel mills, and wastewater treatment centers.

The potential for utilizing algae in combination with power or ethanol plants has been much discussed in the Digest — leading to an affordable source of CO2 for algae cultivation. Combine that with sunlight and a source of water — and a source of organic nutrients — and you have all the essentals for algae cultivation, for food, feed, pharma or fuel production.

Er, except hydrogen. Very useful, in the case of hydrotreating crude algae oils to make hydrocarbon fuels for existing cars, trucks and jets. Now, companies like Sapphire Energy have focused most of their efforts, lately, on making a renewable crude algae oil. Generally, they have considered that hydrotreatment will take place at traditional refineries that already have that technology in place, and a means of producing fossil-based hydrogen onsite, at scale.

But there’s the trick — it’s fossil hydrogen. Subject to the availabilities and costs granted by the global demand and supply of crude oil. Very interesting, as an alternative, to have an alternative supply of hydrogen that its a by-product of wastewater clean-up.

For one application, think space travel – the energy and water problems of which led to the original development of fuel cell technology. In space, there’s wastewater – generally dumped into space, and who knows what would happen in the case of extended lunar or Mars visits. Nice to have a technology on hand that can produce hydrogen, clean water and power, using that waste that would otherwise be dumped. That’s fuel for a return journey (especially if you consider that Mars has sunlight and frozen CO2), drinking, and feedstock for the production of food and plastics.

One step beyond

Take that one step further. Consider the potential for using a hundred-year old French technology called the Sabatier process. In that reaction, hydrogen and CO2 are reacted with a metal catalyst to produce methane and water.

Methane — that we are discovering (using a new class of improved methanogens) that can be an effective source for fuels, via companies like Calysta Energy. Water — well, you just isn’t anything more important and less available in the world of space. You might consider that most of the oxygen for breathing at the International Space Station is provided by transporting water from the Earth.

Remember when the Space Shuttle was going to be wound down, and there was some hard negotiating about the exact date in 2010 and 2011. In mid-2010, on Discovery’s second-to-last-flight, what was amongst the cargo destined for the Internatioal Space Station? Yep, a set of Sabatier hardware. What was NASA doing with the methane? Venting it. Where was the hydrogen coming from? Imported from Planet Earth.

Ah. Now you see. Here is bridging technology that can fill that gap. Consider it an interplanetary source of Gas, Food, Lodging.

But the importance of such a technology might be realized first here on Mother Earth. There are a number of biofuels technologies that can use a source of hydrogen — for example, LanzaTech uses it in converting steel waste gases (think carbon monoxide) into fuels and chemicals.

And here on earth you have a lot more wastewater and CO2 to work with.

Having said that, you’d be surprised how many technologies that are difficult to cost-justify here on the terrestrial surface, become a no-brainer when you think about space. Cargo costs have come down a lot with the commercialization of space — but you are still looking at $2,000-$3,000 per pound to lift a pound of cargo into low orbit. Though Elon Musk projects he’ll get the cost down to $1300 per pound.

Still, that’s more than $10,000 for a gallon of water. Making some of these biotechnologies pretty good candidates for space, long before they might be ready, at scale, here on the planet’s surface.

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