Primer on ammonia fiber expansion pretreatment


Primer on ammonia fiber expansion pretreatment

Publication Type:

Book Chapter


Aqueous Pretreatment of Plant Biomass for Biological and Chemical Conversion to Fuels and Chemicals, JohnWiley & Sons, Ltd., West Sussex, U.K., p.173-204 (2013)






Plant biomass is a plentiful resource which can be used to co-produce fuels, chemicals and nutritional feed, driving forward a nation’s bio-based economy [1]. However, the costs of chemical/biological processes that facilitate the conversion of plant polymers into monomers and finally into desired end-products have sty- mied the development of cellulosic biorefineries [2]. The choice of thermochemical pretreatment has a sub- stantial impact on the economic and environmental viability of biorefineries within the gates of the refinery and beyond [3]. Ammonia fiber expansion, or AFEX (a trademark of MBI International, Lansing), is an ammonia-based pretreatment which has shown tremendous promise at cost-effectively reducing the recalci- trance of lignocellulosics towards biologically catalyzed deconstruction into fermentable sugars. Unlike other aqueous pretreatments, AFEX is a dry-to-dry process (i.e., AFEX-treated biomass composition is unchanged) that reduces plant cell-wall recalcitrance through a unique physicochemical mechanism. The aim of this chapter is to explore the recent advances in AFEX and provide a general overview of this tech- nology from a microscopic (physicochemical mechanisms) and macroscopic (distributed regional process- ing and life-cycle analysis) perspective.