On the Sugar Hunt

December 1, 2010 | 1 Comment

So far the best use of CO2 whether as a fuel use byproduct or already in the atmosphere is get it back to a simple sugar.  From there the sugar’s carbon and hydrogen content can be used to make fuels and other products.  Coming up with useable sugars is the devil in foundation of alternative fuels.  Mastering the carbon cycle with recycling CO2 would solve the fuel as a crisis issue.  Until the process is developed that goes from CO2 directly to fuel is worked out competitive to oil, gas and coal, coming up with a cheap sugar feed stock is critical.

Today vast tracts of land are committed to sugarcane and corn to get cheap sugar.  Massive efforts are underway to gather the sugars in plant’s other structures like cellulose and put those to work.  Now, suppose you had a sugar producing shortcut?

Price parity or better with petroleum products is the threshold of biofuel success.  Getting sugar cheap enough is the cost to control and the price has to be sustainable and look to go down over time.  That’s the cure for petroleum addiction.

The company Proterro is one of the most intriguing entrants in quite a while in the race for cheap sugars. The company’s technology uses sunlight, CO2 and water to create simple sugars that can be utilized as a feedstock for biofuels.

Proterro Company Image. Keep an eye out for this.

That sounds a lot like what algae do, or the Joule technology.  So far algae research is getting to fuel precursors and Joule expects to go directly to fuel.  Proterro is simply making sugar.

The Proterro approach is not to produce sugars in water – but in a thin film bioreactor where the cells are at the surface of a fabric that transports water and nutrients to the organism.

Proterro starts with certain cyanobacteria, which as it happens, naturally produce molecules of interest as an osmotic response to salt stress.  The science is to genetically modify the organism to change the trigger from salt stress to something more easily under the control of the scientists, i.e.to get control over the organisms.

As the Joule process shows and the firm constantly stresses the process is far more than the designer bugs, but in the engineering of the system.  The problem can be explained simply.  Ever opened a can of Coke on a hot day? CO2 doesn’t dissolve into water well in a high concentration. You have to pump CO2 into water, and that takes energy, and removes the CO2 from the surface where the sunlight is.

This is where Proterro borrows from the approach utilized by the leaf. Leaves can transport water and nutrients to a surface layer where CO2 and sunlight are being absorbed. The Proterro approach is not to produce sugars in an aqueous phase – in water – but in a thin film bioreactor where the cells are at the surface of a fabric like the leaf that transports water and nutrients to the organism. The organism secretes, or “sweats” a sucrose solution, which can collected using gravity.

Proterro has proved that its science works, that it can create the simple sugars that it had targeted, and named Protose sugar.  To date, they’ve scaled up from the lab bench to a square meter system – and on their growth list is a larger base module. Then comes a search for partners to move further down the path towards commercialization of the technology.

The simplification and cost control comes from a key difference between most algal-based technologies – which also aim to synthesize low cost sugars from sunlight, CO2 and water. The approach radically reduces the difficulties of getting the water out of the algae, or the algae out of the water. And by radically reducing the amount of water, it radically reduces the land footprint of the overall system.

The goal is a lower production price than Brazilian sugar cane.  Add to that the geographic application has to expand.  Proterro expects that the process will work in relatively northern climates well north of the sugarcane belt. That’s more significant than a first impression might suggest.

An obvious first application in the U.S. is the CO2 from those first-generation corn ethanol plants. The CO2 can be utilized, along with water and sunlight, to generate simple sugars on site that can be fermented into ethanol with equipment in an existing facility.  Without more corn, without land use change, and reducing the potential impact of waste CO2, how much could an existing corn ethanol plant boost capacity by using its own CO2?  A Proterro like microorganism and process could increase ethanol production somewhere in the range of 25-50 percent, according to the earliest, unconfirmed estimates by the company.

That could be a significant opportunity that could add 3-6 billion gallons to US corn ethanol production, without additional land or corn usage, and without expanding the current fleet of plants. It would also begin the process of sharply reducing the CO2 footprint of corn ethanol plants which may qualifying them as an advanced biofuel and opening up additional opportunities under the 36 billion gallons RFS mandate.

The known problem centers on optimizing the flow rates of water – for the amount of hydrogen required to make sugars is relatively small. Proterro has been able to prove that the designer organisms will do their magic, but the design of the reactor and the optimization of rate and yield is the hard work ahead.

Just how productive Proterro will be per land unit area isn’t being stated.  But a certainly is that just like algae the productivity will be quite high.  Just how far north is another interesting question.  What combustion effluent will work well is another.  CO2 from gas fired electrical production and coal generation are two other huge sources of CO2.

Lets say Proterro does come to market as a highly desired profitable way to get more fuel and energy from corn, natural gas or coal.  Suddenly CO2 available already concentrated and cleaned up would have significant value instead of being a cost.

The people behind Proterro seem quite intelligent beyond just the science.  Indications are the firm will look at most reasoned venues for commercialization.  The current backers aren’t hung up on building a non-competing patent protected business model in the face of worldwide innovation.  Rather they suggest they’ll offer the technology on sensible terms to any with the foresight to make money from their CO2 supply.

That company position alone might be the best innovation of 2010.

Hat tip to Al Fin for spotting this.


1 Comment so far

  1. pharmacy technician on December 25, 2010 5:42 PM

    found your site on del.icio.us today and really liked it.. i bookmarked it and will be back to check it out some more later

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