Sweetwater has received final acceptance of its first commercial Sunburst unit at the Sweetwoods Project in Estonia, proving that Sunburst has met all criteria—including energy usage, throughput, and quality of product.

The Sweetwoods project is a Bio-Based Industries Joint Undertaking (BBI JU)-funded venture that uses sustainable hardwood to demonstrate how Sunburst’s breakthrough pretreatment technology, in combination with tailored enzymatic solutions, can provide high-quality lignin and wood sugars at an industrial scale.

“We searched for years for a technology that would meet all our criteria to transform the wood processing industry into a biomaterials and biochemicals industry,” says Peep Pitk, Chief Development Officer of Fibenol OÜ, the lead company in the Sweetwoods consortium. “We are very pleased to announce that Sweetwater’s Sunburst pretreatment has reached agreed performance targets, and has exceeded expectations on steam use, throughput, ease of implementation, and operations. Sunburst has now achieved the Sweetwoods consortium’s goals in a compact, elegant design that converts more than 90 percent of the biomass into useful products.”

Fibenol needed a technology that could efficiently process different wood species into high- purity cellulosic sugars and lignin, while having a minimal physical and ecological footprint. The Sunburst pretreatment module requires less than 250 square meters to convert wood flakes into easily pumpable homogenous liquified wood slurry.

On top of that, the Sunburst pretreatment system has proven itself incredibly reliable, reaching full commissioning in fewer than 30 runs and taking less than 45 minutes from startup of the system to reach in-spec conditions. Its output products are highly pure and largely free of unwanted byproducts, making the industry’s dream of a true biomass biorefinery possible.

“Commissioning of Sunburst started within two years of signing the agreement for the Sunburst equipment, even despite the pandemic—a testament to the ease of implementation of the technology,” says Arunas Chesonis, Chairman and CEO of Sweetwater. “Our team, led by Director of Commercialization Sharon Samjitsingh, definitively proved that Sunburst excels at commercial scale. We are excited for how this will enable the production of sustainable fuels and materials while helping to mitigate climate change.”

The high quality of Sunburst’s sugar has already translated into top fermentation performances for the production of bio-isobutene—a key ingredient to replace fossil-based products in the energy, materials and cosmetics markets. Global Bioenergies’ Director for Industrial Strategy Bernard Chaud says, “As a partner in the Sweetwoods Consortium we tested the new Sunburst’s cellulosic sugars at pilot scale and found that they allow for the high productivity of bio-isobutene with similar performances compared to traditional sugars. The consortium has already initiated demo-scale bio-isobutene production, and conversion of this bio-isobutene into renewable aviation gasoline was successfully demonstrated.”

None of this could have been possible without the dedication of the team at Sweetwater and their counterparts at Fibenol OÜ in Estonia. As Samjitsingh says, “Working through the pandemic on this first-of-its-kind technology was demanding, but always enjoyable because of the camaraderie and alignment of the Sweetwater and Fibenol teams. It was very fulfilling for all involved.”

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