WIST Biofuels Research
WIST successfully developed a fermentation laboratory at UW-Stevens Point and a Cellulose Pilot and Processing Center at Wausau, Wisconsin, as part of a public-private partnership. WIST researchers secured several patents related to isoprene and renewable fuels, worked with a number of paper and pulp mills to characterize opportunities to achieve value from waste streams, and published several papers relating their research to other researchers and the public. WIST research in biofuels has ended because grants supporting this work have ended.
Renewable Alternatives to Fossil Fuels
We aim to develop a fermentative unit to produce isoprene, an energy-dense hydrocarbon fuel precursor that can be used to manufacture numerous grades of fuel and serve as a platform chemical for production of polymers and other materials. Isoprene is a valuable feedstock used in the production of latex, rubber, plastics and pharmaceuticals, and it can also be used to produce liquid aviation fuels using inorganic catalyst technologies that currently exist in the petroleum industry. Our goal is to develop an isoprene production unit that will integrate with a lignocellulosic biorefinery we are developing. This unit will use engineered microbes to ferment wood sugars to isoprene and capture the isoprene from the vapor phase above the fermentation vessel. We have demonstrated these processes at the laboratory scale and are now deploying at the pilot scale.
We propose to produce isoprene from pulp and paper mill waste streams commonly referred to as residuals. Cellulosic solids comprise the major component of these residuals. In the mill, residuals are either isolated and concentrated in solid form or biologically treated in a waste treatment facility. Residuals concentrated in solid form are commonly referred to as sludge and typically landfilled at the mill’s expense. Using this sludge to produce isoprene provides pulp and paper producers an opportunity to diversify their product stream and create new jobs while reducing waste. WIST researchers have demonstrated a proof-of-concept isoprene fermentation system by transforming E. coli with multiple genes from the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway residing on multiple plasmids. These cell lines have produced isoprene from glucose, hydrolyzed cellulose, and hydrolyzed pulp mill sludge.
WIST Researchers Granted Patent
The patent protects the invention of an economically viable method to separate biomass into its constituent lignin, cellulose and hemicellulose. The cellulose can be converted to sugars to make cellulosic biofuels: sustainably sourced fuels that don't impact the food supply. The process has been proven at pilot scale and WIST seeks partners to commercialize the technology. Other techniques exist to separate lignin from cellulose and have long been used in the paper industry. However, these processes result in cellulose that contains inhibitors that make it more difficult to convert it to sugars. Similarly, the lignin produced contains additional chemicals not easily or economically separated. Paper mills may license the WIST process to capture a new revenue source in their operations.
A number of energy- and business-related publications, such as Biofuels Journal, picked up the story.