Novel Deep Eutectic System
Andreas Sebastian Bommarius, Rolf Michael Hertel, Matthew James Realff, and Yuzhi Kang
The invention is a novel eutectic solvent system to facilitate the enzymatic conversion of cellulose into glucose for use as a biofuel and food source. Cellulose, the most abundant renewable biomaterial known, can be hydrolyzed to glucose and used as a food supplement or further processed to obtain ethanol for use as a replacement to fossil fuel-based energy. However, cellulose has not yet reached its potential as a biofuel or food source because it cannot be processed economically. The bottleneck in this context is the insolubility of cellulose in common inexpensive solvents. Due to the insolubility of cellulose in water, a low cost and environmentally benign solvent is needed for large scale applications. Efforts thus far have focused on the development of ionic liquids to obtain dissolution of cellulose. However, ionic liquids have proven to be costly with toxic results.
Eutectic mixtures of salts as used in this novel innovation provide a solvent that is less toxic, easy to prepare, less water-sensitive and lower cost than existing technology. A eutectic system is a mixture of at least two compounds that solidifies at lower temperature than either one of the components in their pure state. The solvents within this system exhibit good conductivity and moisture stability, both excellent characteristics to promote solubility of cellulose. To differentiate these mixtures, the term Deep Eutectic Solvents (DES) was introduced which refers to eutectic mixtures that are liquid at or below room temperature.
Much research has focused on the digestion of cellulose into glucose. The generated glucose can be used to produce single cell protein as food for livestock and even as a human food source. Glucose can also be used as the starting raw material in the production of a wide variety of energy fuels. Glucose can be easily fermented to ethanol that can be used as gasoline or processed further to make other common petrochemicals. Because raw cellulose is abundant in various forms and the resource is renewable, the world will likely depend on it heavily for food, fuel, chemical supplies and raw materials in the future.
Currently, the commercial and geopolitical value of cellulose as an energy source is at a critical level. The quest for energy security, economic development and environmental quality has driven a few nations to follow the lead of Brazil in development of a domestic biofuels markets. The growth profile for ethanol biofuels from 2009 to 2022 shows a world market CAGR of 9%. This is based on biofuels consumption mandates by national governments. Ethanol biofuels are projected to surpass $200 billion by 2022 (Pike Research). The increased availability of flex-fuel vehicles will enable the use of higher percentage blends of ethanol and remove demand barriers.
This technology will improve the sustainability of biofuels as well as economically increase renewable food sources for the world’s growing population. Both of these applications will create an increasing demand for this emerging technology.
Advantages of this technology:
• Less expensive and less toxic than existing solvent systems
• Easy solvent preparation
• 10% to 15% decrease in crystallinity of cellulose assists in cellulose degradation
• Faster enzymatic conversion of cellulose to glucose
Applications of this technology:
• Hydrolysis of cellulose to glucose for use in biofuels
• Conversion of cellulose to a food source for the food manufacturing industry
• Solvent for dissolving cellulose, starch, lignin, synthetic polymers, and others not soluble in other media
Biological pretreatment of cellulose: enhancing enzymatic hydrolysis rate using cellulose-binding domains from cellulases. 2011. M. Hall, P. Bansal, J.H. Lee, M.J. Realff, A.S. Bommarius. Bioresour Technol. 2011 Feb;102(3):2910-5.
A U.S. Patent Application has been filed for this technology.
Marie-Christine Reames, Assistant Director
Georgia Tech Research Corporation, Office of Technology Licensing