The U.S. Department of Energy has granted US$2.5 mln for a Texas A&M AgriLife Research study to find ways to use biorefinery waste to make new, marketable products. Dr. Joshua Yuan, a biotechnologist, is the lead scientist on the project that will primarily focus on ways to make plastic materials from the lignin waste. "In the biorefinery field, we have a saying: You can make anything but money out of lignin. And yet, that is the majority of waste or what’s left over in the biorefinery plants. Until we resolve this problem, biorefinery is not going to become economically viable", says Dr Yuan.
Yuan and his team, who have been researching the sustainability of biofuel for years, will focus much of the three-year study on ways to make plastic materials from the lignin waste. His lab has other energy department grants US$4.9 mln focused on use of plants to directly produce hydrocarbons at a higher yield; and US$2.4 mln to design a microorganism to convert lignin to lipids, or fatty acids, for fuel. But the researcher said the new grant points to the philosophy behind biofuel – helping the U.S. create an alternative fuel source – in that it must be a sustainable, non-wasteful industry.
Yuan said about billions of dollars have been invested in the U.S. toward creating a modern biorefinery industry, and progress has been made in terms of plants such as switchgrass, sorghum, energy cane and other grass-type plants to produce fuel. But all of those plants leave lignin, the stiff, almost woody cell wall material, after the fuel is extracted. Rather than try to burn it or otherwise dispose of it leaving an impact on the environment, he said, biorefineries prefer using the byproduct in additional products, which would help their overall bottom line. This new project will use the biorefinery waste to develop plastic materials that could then be used to make other products, which in turn would be recyclable. "We’re hoping to help create an integrated biorefinery that will not only produce ethanol but also produce a lot of good and useful products out of this waste,” Yuan said.
In a corn refinery where ethanol is produced, for example, the waste can be used for animal feed and to make corn oil, he noted. In a petroleum refinery, along with gasoline, diesel and kerosene, the leftover becomes asphalt. “That is the model we seek for the grassy plant materials — to produce ethanol as the main product, but in the meantime to also produce bioplastics,” Yuan said. “When we talk about renewable energy or renewable fuel, there are two important considerations: One is economic. It has to be product cost effective. We cannot compete with $30-per-barrel petroleum — it has to be more like $80-per-barrel petroleum for a biorefinery to complete, unless we have another product for which we can use the waste to make something wonderful.”
Yuan said his team will work with an engineered microorganism that is able to convert lignin to plastic while also concentrating on maximizing the amount of plastic that can be made from the waste. Two commercial partners and several biorefinery companies are collaborating with Yuan’s team, which includes researchers with the University of Tennessee and Washington State University.