California-based Cobalt Technologies, a company using strain development and bioprocess technology to optimize biobutanol production (earlier post), has successfully produced biobutanol from beetle-killed lodgepole pine feedstock.
Cobalt combined a non-enzymatic pretreatment process derived from the pulp and paper industry to release the C5 and C6 sugars from the pine, followed by fermentation with Cobalt’s optimized bacteria. An additional challenge in such processing of pine for cellulosic biofuels, said Dr. Rick Wilson, Cobalt’s CEO, is the sap, which contains terpenes, a large and varied class of hydrocarbons which can be toxic to yeast and bacteria used in fermentation.
|“Converting beetle-killed pine for biofuels is an extremely difficult process. If Cobalt can convert beetle-killed wood, it’s likely that the company can make biofuel from almost any cellulosic feedstock.”|
|—Ken Reardon, professor of Chemical and Biological Engineering at Colorado State University|
Cobalt’s pretreatment process removes most of the terpenes, and uses them for process heat, Wilson said. In addition, Cobalt’s engineered bacteria are very resistant.
To evaluate the fuel’s viability for commercial vehicles, the company has signed a fuel testing partnership with Colorado State University. The fuel testing will be performed at Colorado State University’s Engines and Energy Conversion Laboratory under the auspices of the University’s Sustainable Bioenergy Development Center.
Harvesting beetle-killed trees could produce low-carbon fuels and chemicals, establish a foundation for a sustainable biorefinery industry and create jobs, particularly in rural areas. If we use only half of the 2.3 million acres currently affected in Colorado alone, we could produce over two billion gallons of biobutanol—enough to blend into all the gasoline used in Colorado for six years.
—Dr. Rick Wilson
Colorado’s pine forests have been devastated by the mountain pine beetle, which has infested nearly half of the state’s five million acres of pine forest. Additionally, millions of acres of lodgepole and ponderosa pines across the Western United States and Canada have been infested, with 40 million acres in British Columbia alone. From Canada to the Mexican border, the destructive path of the pine beetle has left brown, dead trees, which have little use, pose a significant fire hazard and threaten communities.
A 2006 study by Natural Resources Canada and the Canadian Forest Service on the usability of beetle-killed pine noted that:
It is anticipated that existing processing sectors can use much of this timber volume [beetle-killed pine], but approximately 200 million m3 of this total is expected to remain unsalvaged over the next decade unless creative new uses can be found for this massive volume of fibre. Although this indicates a large potential supply of feedstock for energy purposes, much of it will be uneconomic. The supply potential of this feedstock will be defined by two economic margins—the intensive and extensive margins.
Availability at the intensive margin arises from more fully utilizing fibre on a given area of land, i.e., increased utilization. Availability from the extensive margin arises from expanding the area harvested. Most of the available economic supply of feedstock for energy is that available at the intensive margin, including residuals, and low-valued timber within stands with a mix of higher quality stems that would not be of sufficient grade to justify manufacturing activities.
A further complication is that the longer beetle-killed timber remains standing, the less options are available for using the fibre. Eventually, the decomposition of this dead timber renders it useless, even for energy production. Therefore, as stands are salvage- harvested over time for processing into lumber or other traditional forest products, the supply of non-suitable timber per hectare will increase as higher proportions of trees within a stand fall below the quality threshold for lumber production or other manufacturing.
—“Bioenergy options for woody feedstock”, 2006
Speed is an issue with processing the killed pine, Wilson said, as is the cost of removal. Sugars do degrade over time, and the overall yield will go down. However, a program in place in the US will pay half the cost of the removal. Wilson said that Cobalt is in discussions with a prominent Canadian investor over the process and potential. The earliest large-scale commercial plants could be in place is likely 2013 or 2014, Wilson said.
Cobalt is also considering licensing its pre-treatment process to other cellulosic biofuels companies, he said.
Cobalt Technologies converts non-food feedstock, such as forest waste and mill residues into n-butanol, a versatile product that can be used as a drop-in biofuel to be blended with gasoline, diesel and ethanol; converted into jet fuel or plastics, or sold as is for use in paints, cleaners, adhesives and flavorings.
Cobalt is backed by leading investors in the cleantech sector, including Pinnacle Ventures, Vantage Point Venture Partners, Burrill and Company, Malaysian Life Sciences Capital Fund, Life Science Partners (LSP), @Ventures, and Harris & Harris.
Bioenergy options for woody feedstock: are trees killed by mountain pine beetle in British Columbia a viable bioenergy resource? (Natural Resources Canada, Canadian Forest Service; BC-X-405)