A Novel Extractive Ammonia Fiber Expansion (AFEX) Process



In the continuing push to develop alternative fuels, bioethanol is clearly a viable option. However, if it is to become a truly economical alternative, a more effective and efficient method of processing lignocellulosic biomass must be developed.


Description of Technology 


Michigan State University has developed a novel lignocellulosic biomass pretreatment process that results in the formation of highly digestible cellulose III allomorph. The method also provides the option to simultaneously extract biologically inhibitory cell-wall extracts such as lignin, lignin decomposition products, xylo-oligosaccharides, and amides using essentially anhydrous liquid ammonia pretreatment (ALAP). This is important because cellulose crystallinity, lignin-carbohydrate complex (LCC) ester linkages, and non-specific enzymes binding to cell wall components (like lignin) are the major rate-limiting steps to efficient cell wall deconstruction. Non-crystalline cellulose (known as amorphous cellulose) has a four-to-five-times higher rate of enzymatic hydrolysis than native crystalline cellulose.


Key Benefits

  • More readily digestible product: The ALAP process produces amorphous cellulose, which is considered a more highly digestible form of cellulose than native cellulose I.
  • Flexibility: Two streams are created by the process: one rich in cellulose and the other in hemicellulose-lignin. Each stream has the potential to be used to produce different products.



  • Cellulosic biofuels: The invention would be beneficial to companies focusing on novel lignocellulosic biofuel production processes.
  • Biomaterials: The resultant lignin fraction has potential to be used for the production of various biomaterials.


Patent Status


Patent pending




Shishir Chundawat, Leonardo da Costa Sousa, Albert Cheh, Venkatesh Balan, Bruce Dale


Tech ID




Learn more about the Great Lakes Bioenergy Research Center (GLBRC) at MSU 


Patent Information:


For Information, Contact:

Thomas Herlache
Assistant Director
Michigan State University