All I Need is the Air That I Breathed: Microbial Dairies using CO2, sunlight and water

December 4, 2014 |

e-cowliTake CO2, add water and an energy source: voila, Fuels & Chemicals from Microbial Dairies.

We revisit 3 top practitioners of the art and one outlier, and their progress.

Elsewhere in the Digest today we have a Sam Rushing’s “CO2 recycling from biofuels and allied chemical and energy projects” — looking at CO2 sources ranging from power plants to industrial fermentation itself, and including a look at delivery systems.

But, what do you do with all that CO2? How about feeding it to a microbial organism which then secretes a targeted fuel or chemical at competitive prices with fossil sources, or less?

There are a number of technologies based on the dairy model, or “milking mode”, where the organisms are optimized to secrete targeted products, which are recovered from a broth surrounding them. In this case, a number of technology developers are still of the opinion that fuels-grade economics are possible, though speciality chemicals may also be produced to sweeten the margins. And in this case, the organisms are photoautotropic (meaning they get energy from sunlight, and carbon from CO2).

Now, plants utilize CO2, sunlight and water — many microalgae do too. But, increasingly, extraction-based algae technologies have turned to heterotrophic fermentation (i.e., grown in the dark and utilizing sugar as a carbon and energy source) to get the process economics needed to move into speciality chemicals and beyond nutraceuticals. These are the beef cattle of the microbial world — fattened up in the feedlot (fermenter), and then taken to the abbatoir (harvest/extraction) where target products are separated.

Let’s get away from the beef cattle and get over to the dairy, and look at four companies which exemplify the trends.


#3 Hottest company in the advanced bioeconomy

Input: CO2, sunlight, water, nutrients
Output: ethanol, upgradable to diesel, jet fuel or chemicals
Location: Ft. Myers, Florida

Algenol Hot 50 Submission - Plate

Last fall, we highlighted a series of videos from Algenol as it turns towards scale. In many ways, the front end of the Algenol process works likes the above-described microbial dairy — the blue-green algae consume CO2 as they bathe in warm water, heated by Florida’s hot sun. They sweat out pure ethanol, which is recovered. Then the algae, following harvest, are then converted using relatively standard refining techniques into diesel, gasoline and jet fuel.

By-products? Algenol makes around 1.4 gallons of fresh water for every gallon of fuel.

Now, these are modified microbes — optimized to produce at fast rates — a primary reason why Algenol has been able to generate a sustained production of 8,000 gallons of ethanol, per acre, per year — with peaks as high as 9,000.

That’s more than 16 times the productivity of corn, 9 times that of sugarcane — and, as you might surmise, as long as the accompanying plot of land has access to sunlight, water and CO2, you can place it anywhere. In the middle of a desert, if you like, and the logistics were in place. No need to use land that competes with, say, the food chain. Or even the Food Giant.

Now, if Algenol’s process churned out $4 per gallon fuel, there probably would be an extended conversation about subsidies and infrastructure — whether the world really needs alternative fuels that cost more than the incumbent, and who pays for the cost difference.

But at $1.27, the conversation, ahem, changes. Same as is happening for low-cost compressed natural gas — being adopted by fleets in increasing numbers around the United States and Canada, because the cost of natural gas has stayed so persistently low.

More on Algenol here.

Joule Unlimited

#27 Hottest company in the advanced bioeconomy

Input: CO2, sunlight, water, nutrients
Output: ethanol, diesel, jet fuel or chemicals
Location: Hobbs, Texas


We reported in September that “Joule has increasingly turned to global development in 2014”, intending to commercially develop diesel fuel and also bring products to market via strategic development partnerships. The company is now commercializing its first product, Sunflow-E, for global availability in early 2015. Construction of the company’s first commercial plants is planned to begin in 2014 in multiple locations worldwide as the company plans to expand.

Joule is trying to make a robust, economically viable strain of an alkanogen, alkeneogen or ethanologen. If you’re wondering exactly what makes that a) interesting and b) hard to do, we’ll try to explain.

Any insertyourtargetproduct-ogen is a rare and precious bird in the biofuels and chemicals trade. Reasonably well known from nature are methanogens and acetogens. These are organisms that secrete acetic acid or methane as part of their metabolic cycle. All humans, to make the comparison, are sweatogens. You labor, and your body secretes a sweat. Among mammals, almost all mothers secrete mother’s milk.

In this way, an ethanologen, alkeneogen or alkanogen is an organism that sweats ethanol, alkenes or alkanes. All you basically have to do is collect it, like milking a cow. Making Joule even more interesting — its organisms are trained to sweat diesel-range alkanes, or chemically high-value alkenes like ethylene or propylene. Or alcohols like ethanol.

What’s going on behind the scenes in the world of Joule? Generally, the work falls in four areas.

1. Getting the organism to over-produce the alkane, alkene or alcohol of interest.
2. Getting a cost efficient photobioreactor design.
3. Controlling heat. Systems heat up in the day, when the sun is out. Cooling costs money.
4. Looking at ways to extend an organism’s productivity from “daylight hours” to “round the clock”.

We highlighted the state of play here.


Input: CO2, sunlight, water, nutrients
Output: sucrose
Location: Orlando, Florida


Two reasons to look very, very closely at Proterro.

First, they are aiming to produce low-cost industrial sugars — the much-desired intermediate that could power a whole raft of new price-competitive fuels and chemicals from the likes of Amyris, Solzyme and REG Life Sciences.

Second, Proterro is not building a liquid-phase or gas-phase system — essentially, it’s solid state. Rather than bathing the organism in water (as in the case of fermentation vessels), the cyanobacteria is kept moist by a water-dripping system (that also ultimately captures the sucrose that the cyanobacteria is secreting – with gravity pulling the drips down into a collector). Which means that one of the technical problems that has puzzled other companies, keeping the water temperature from creeping up so high that it impedes the organism’s productivity — is not really a factor here.

In September, we reported that Proterro and Bunge will conduct a pilot study of Proterro’s sucrose-production technology in Brazil. Under a joint development agreement, a pilot plant is being commissioned at Bunge’s Moema Fazenda sugarcane mill, where two of Proterro’s photobioreactors have been installed to cultivate Proterro’s cyanobacteria for production of fermentable sugars for ethanol production.

The Bunge pilot plant will replicate the operations of Proterro’s U.S. pilot plant in Orlando, Florida, where four photobioreactors are currently deployed. “Testing performed at this site in Brazil is particularly valuable to our development and progress, as it represents a climate, geography and CO2 source that are representative of our anticipated commercial production plant,” said Proterro CEO Kef Kasdin.

Proterro’s photobioreactor, cyanobacteria and its entire sugar-making process have been granted patents by the United States Patent and Trademark Office. Specifically, based on U.S. Patent Application 13/737,201, allowed device claims describe a photobioreactor for cultivating Proterro’s unique cyanobacteria or other photosynthetic microorganism, explained Proterro CEO Kef Kasdin. “The claims describe a photobioreactor that includes a non-horizontal, solid cultivation support and a physical barrier over the cultivation support,” she said. “They also describe integration of systems for optimizing light, water supply and sugar collection.”

In the case of Proterro, rather than reaching scale by building larger and larger primary fermentation vats, the company has a modular design, and reaches scale by multiplying out the number of modules employed. So, there’s less scale-up risk from pilot to commercial, because the unit only gets so big.

The next (demonstration step) goes beyond proving out that the core technology works as intended. In the pilot, the system is feeding CO2 to the organisms in a lab-like manner — the demonstration step is where as many as 100 reactor modules will be linked to a CO2 distribution system — think of it somewhat as moving from cooling yourself with a fan to cooling yourself with a house-wide air conditioning system.

More on Proterro here.

An outlier: Liquid Light

There’s no organism here, no biomass at all. Just good old-fashioned catalytic chemistry making valuable stuff out of low-value CO2. That’s Liquid Light, which the Digest’s readers voted the #1 Hottest small company in the advanced bioeconomy for 2014-15.  What gives?

Input: CO2, water, electricity
Output: propylene, isopropanol, methyl-methacrylate and acetic acid.
Location: Princeton, New Jersey


Liquid Light emerged from stealth mode in the past year, and focuses on electrocatalytic conversion of CO2 to useful fuels and chemicals. The company’s first process is for the production of ethylene glycol (MEG), with a $27 billion annual market.

In measuring progress, the company notes that “Results consistent with cost-advantaged production have been validated at lab scale for key parts of our process. Ultimately, the company has opportunities in propylene, isopropanol, methyl-methacrylate and acetic acid.”

A very interesting advance appeared in July in the Journal of CO2 Utilization. A research team from Princeton, using Liquid Light catalysts and specially-designed reactor cells , demonstrated that it was possible to produce formates.

What makes it especially interesting is that they used a standard solar panel to power the set of electrocatalytic reaction cells. The project confirmed that renewable power, in this case solar, worked as a power source, and that the intermittent, sometimes-unpredictable nature of renewable sources did not negatively impact process efficiency.

There have been attempts to make formates directly from sunlight before. None have reached the basic processing efficiency benchmark, which was to match or exceed the conversion efficiency of natural photosynthesis.

In this case, the results were as much as 9X better than the best previously reported results by industry or research labs, for converting solar energy to formates, and roughly 2X better than photosynthesis.

More about Liquid Light here.


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