Proterro meets key milestones, commissions pilot plant

By Proterro Inc. | October 01, 2013

Proterro Inc., the only biofeedstock company that actually makes sucrose instead of extracting it from crops or deconstructing cellulosic materials, has  met key new development milestones.

“We scaled up our novel photobioreactor design and conducted independent functionality tests  that confirmed the unit’s robustness,” said Proterro CEO Kef Kasdin. “The modular  photobioreactors, which are made from off-the-shelf materials, including polyethylene, can withstand category 1 hurricane winds,” she explained, adding, “Because of the materials used  and the innovative design, we also have been able to validate low fabrication costs.”

Kasdin also said that Proterro is in the process of commissioning a pilot plant in Florida and—with the help of top-ranking U.S. engineering, architectural and management services company Middough Inc.—has completed a preliminary design, layout and associated cost estimate for a demonstration-scale plant.

Using CO2, sunlight and water, Proterro lowers the cost of sugar production through a novel, scalable biosynthetic process that integrates its patented, highly productive microorganism with its unique, patent-pending photobioreactor. This process yields a fermentation-ready sucrose stream, rather than a mixture of sugars, allowing simple, low-cost downstream processing.

Key features of Proterro’s patent-pending photobioreactor are:

*Collapsible low-cost polyethylene cylinder

*Made from off-the-shelf materials

*Naturally sheds rain and snow

* Favorable aerodynamic shape for wind loading

* Patented cyanobacteria grow on vertical fabric panels

* Water and nutrients drain by gravity on panels

* CO2-augmented air, or flue gas inflates cylinder

* Natural low point for condensate drain

* Can be UV stabilized

“Unlike typical algae cultivation approaches,” said Kasdin, “we grow our high-sugarproducing cyanobacteria on a composite fabric substrate enclosed in our photobioreactor,  which optimizes the organisms’ access to light and surrounds them with their carbon-dioxide feedstock. Water and nutrients are trickled into the photobioreactor, creating a controlled cultivation environment.”

Proterro’s unique sugar-making process removes the price volatility that comes with crop-based feedstocks and eliminates the complex and costly steps required to produce cellulosic sugars derived from biomass. The result is an economically stable, fermentation-ready sugar feedstock for the scalable, affordable production of a variety of commercial scale fuels and chemicals through standard industrial fermentation methods.