Companies turn CO2 into C3 sugars, adding to biomass-based model

By Sue Retka Schill | October 24, 2013

Sweetwater Energy Inc. and Naturally Scientific Technologies Ltd. are expanding their relationship, announcing a joint venture to produce sugar from waste carbon dioxide. It will use technology developed by the U.K.-based Naturally Scientific Technologies Ltd. that can convert carbon dioxide emissions from facilities such as ethanol plants or natural-gas powered power plants into simple sugars.

“It’s exciting to be able to take a greenhouse gas like carbon dioxide that is being vented into the atmosphere, turn it into sugar, and ultimately into useful products like biofuels and bioplastics,” says Arunas Chesonis, chairman and CEO of Sweetwater. “The team at Naturally Scientific has developed a truly remarkable process. The more we learned, the more we realized that a joint venture between our companies to expand our feedstock portfolio beyond biomass was going to have a tremendous impact on the industry. The flexibility we now have to address both a customer’s sugar needs and emission issues is extraordinary.”

“We’re thrilled about the potential in this joint venture with Sweetwater,” says Geoff Dixon, CEO of Naturally Scientific. “Their expertise in sugar platform technologies meshed so well with our own aims that this venture is a sweet deal in every sense of the word.”

Naturally Scientific has spent five years creating its modular, rapid-growth and high-yield bio-manufacturing platform. The company has a demonstration plant in Nottingham, U.K., that has been fully operational for two years, producing sugar and vegetable oils from carbon dioxide. In the two-stage process, CO2 is first converted to C3 glyceraldehyde, which Chesonis explains can be used in biochemical processes as an economical replacement for dextrose. Alternatively, Naturally Scientific’s Stage 2 process takes the C3s, or other sugars including C5 or C6s, and converts those into vegetable oils. Those oils can be used as feedstocks for diesel or jet fuel production or in biochemical facilities.

Earlier this year, a $250 million joint venture between the two companies was announced where Naturally Scientific will build a facility in Rochester, N.Y. “They’re going to break ground next month, building a plant that will make oil,” Chesonis said. “Instead of them using CO2 to make oil, Sweetwater is going to use wood chips and make C5 and C6 sugars. We’ll feed their Stage 2 plant where they’ll make high value vegetable oil for the chemical industry.”  Chesonis added the 10,000 ton-per-year plant is expected to be operational next summer.

The joint venture will add flexibility and synergies to Sweetwater’s business model targeting the ethanol industry. Sweetwater’s process produces C5 and C6 sugars from biomass for sale to ethanol producers as a supplemental feedstock. The new concept will add a layer of new coproducts with Sweetwater capturing the carbon dioxide emissions from the ethanol plants, utilizing Naturally Scientific’s Stage 1 process to convert the CO2 to C3 glyceraldehydes. The process could end there, with the C3s being sold to chemical companies, or be continued using the Stage 2 process for conversion into vegetable oil.

Sweetwater already has two 15-year offtake agreements signed with ACE Ethanol LLC and Front Range Energy LLC. The ethanol producers will use the biomass-based sugars to replace up to 7 percent of their corn feedstock for ethanol production.  “They can use the C6s initially,” Chesonis said. “And, we’re currently testing the ability to use the C5 sugars, which will require special yeast.” 

Chesonis said the land acquisition and permitting processes are close to being finalized for the Sweetwater plant to be co-located at ACE Ethanol’s plant in Stanley, Wis. “We should be able to break ground soon.” In Windsor, Colo., it has taken longer to arrange the land acquisition near Front Range Energy, and the permitting process is just beginning.