Bioreactors on a Chip Renew Promises for Algal Biofuels

by Alexa M. Schmitz (Cornell University/Biomass Magazine) ... This week, researchers from the Cornell-affiliated Boyce Thompson Institute and Texas A&M University report in Plant Direct exciting new technology that may revolutionize the search for the perfect algal strain: algal droplet bioreactors on a chip.

A single algal cell is captured in a tiny droplet of water encapsulated by oil—imagine the tiny droplets that form when you mix vegetable oil with water—then millions of algal droplets squeeze onto a chip about the size of a quarter. Each droplet is a micro-bioreactor, a highly controlled environment in which algal cells can grow and replicate for several days, forming a genetically homogenous colony that goes through its typical biological reactions, including the production of lipids.

“This is the first microsystem that allows both lipid content analysis and growth-rate measurement at high throughput, whereas previous work could only do one or the other,” said senior author and engineer Arum Han of Texas A&M.

Scientists are racing to identify a super algal strain that can reproduce faster and produce more lipid per cell. This summer, ExxonMobil announced the discovery of a strain with a single genetic modification that allows for twice as much lipid production per cell. But this is only a step in the right direction, as thousands of genes hold potential for further improving both traits.

With today’s gene-editing technologies, modifying algal genes can be relatively straightforward; however, identifying which genes to target is time-consuming and costly. Exposing an algal culture to a mutagen yields millions of unique, potentially improved algal cells that must each be tested for expression of a desired trait, such as increased lipid production. Mutated genes can then be identified through whole-genome sequencing.

“The important thing is to develop a tool that can screen millions of cells in a much shorter time frame and a smaller space. In a chip housing millions of droplets of cells, each droplet is like a flask or a bioreactor, and that’s how we can get results faster from just a tiny chip,” explained author and BTI postdoc Shih-Chi Hsu. READ MORE Abstract (Plant Direct)

Excerpts from Biofuels Digest: The Big However -- According to results reported at Cellana’s algae demonstration farm in Kona, Hawaii — they’re able to sustain just shy of 23 grams of algae growth per square meter per day with nannochloropsis, an established production algae whose varietals have a lipid content of between 37% and 60% (check this review, here.)

Translating that into easier-to-compare terrestrial numbers, that’s 78 tons of biomass per hectare per year (reported here) and, using the lowest-end lipid content numbers, and about 31 tons of oil. If you prefer to think in acres, think 14 tons of oil.

By contrast, a soybean operation that does well might generate 0.3-0.5 tons of oil per acre per year — and soybeans remain the number one source for biodiesel raw materials in the United States, and deservedly so based on production volume and cost.

Suggestive that algae productivity isn’t the problem, and that the problem has been for some time finding a way to grow algae in a controlled, harvestable environment instead of its wild environments in ponds and on oceans. In other words, domesticating the crop.

So, where are the algae fuel gallons?

The world is replete in fuel-based farms on the drawing boards that have good economics and weren’t built.

Probably for the same reason that you, yourself, right now, are not investing your 401(k), IRA, or spare cash into algae — or many other investment opportunities that can offer attractive terms.

Where are you putting your money? Most people invest in publicly-held stocks, established companies, and bonds. Why? The risks of small-cap, private investment are difficult for investors to bear, and the accumulations of capital to raise domestic algae at fuel-economic scales are not for the faint of heart.

You can point a finger at oil prices which are at 10-year lows — but no one was building algae farms in 2003 when oil prices were, adjusted for inflation, also low. Some of that has to do with the march of technology — algae tech is better today than back then. But we don’t see Cyanotech expanding, either — and they make spirulina and astaxanthin at world-dominant scale and we live in times that people are paying big premiums for specialized consumables with health benefits.

Back to the Four Why Nots

Above, we identified four reasons for algae’s slow progress as a crop platform that can provide competition to corn and soybeans — much less petroleum.

1. The cost of algae day care. Yield always matters, but the productivity of algae is not its most compelling problem. The cost of keeping it wet for growth and then getting it dry for use, is. This effort to develop magnetic algae at Los Alamos we thought was an interesting attack on a real problem.. Others will emerge, but one of the things you learn that are cool about grasses like corn is that dirt is cheap and that, at maturity, grasses stick out of the growth medium, making harvest a snap.

2. Business plans focused on a single use case with historically uncertain margins. Even motion pictures have better business plans that industrial biotechnology – based on a cascading set of time-based windows with higher prices now, and lower-prices later. Few algae technologies have really well-developed offtakes with smaller-volume, higher-margin customers and higher-volume, lower-margin customers — and a venture begins, and a lab experiment ends, with the arrival of a customer.

3. Use cases based in drop-in solutions with higher costs to customers offset by compelling public benefits (emissions, energy security, employment) that the public is generally unwilling to pay for over the long-term. Drop-in fuels that compete with $40 oil are almost always going to find a home, but not drop-in fuels that compete with $90 oil. Given the fickle nature of public support, algae fuel need to find public appeal based on differentiation, and not just the kind that shows up in arcane emissions math.

4. Investor preference for technologies that deliver benefits to established crops vs novel crops with big potential markets. You can raise a lot of money for a web-based service, but try raising money for an alternative to the World Wide Web. Given that algae is novel and there’s no way around it, what’s the solution? Scarcity; establishing farms where there are no farms — food security, fuel security, simplified logistics are reasonably proven-out reasons for investment rationales for taking a leap into novel technologies that doesn’t provide a novel benefit. Sometimes, the best way to sell an unproven lifeboat is to put a salesman onto the Titanic. READ MORE