(608e) Development of the Extractive-AFEXTM (E-AFEXTM) Pretreatment Process

The ammonia fiber expansion or AFEX™ process is a leading thermochemical pretreatment process that facilitates the rapid deconstruction of lignocellulosic biomass to fermentable sugars in an economical fashion. Two major limitations of the conventional AFEX™ process are; (i) it is unable to reduce the inherent recalcitrance of crystalline cellulose I to enzyme biocatalysis, and (ii) it is unable to extract any lignin during the process that are potentially inhibitory to biological catalysts. In order to address these limitations, we have recently developed a novel ammonia based pretreatment called Extractive-AFEX™ (or E-AFEX™). One of the driving forces that led to the development of the E-AFEX™ process was based on our recent discoveries related to unique physicochemical properties of cellulose III (a less recalcitrant allomorph of cellulose; Chundawat et al, 2011, JACS, 133:11163). Fortuitously, the conditions that favor cellulose III formation also facilitate selective extraction of lignin from plant cell walls during the pretreatment. In this presentation, we will explore the salient features of the E-AFEX™ technology and its impact on the enzymatic and microbial processability of lignocellulosic biomass. The E-AFEX™ process is able to overcome several of the common bottlenecks to cellulosic biofuel production and can be readily integrated within a non-centralized biomass processing framework. Additionally, the lignin extracted during the process can be converted to valuable chemicals or materials. AFEX™ and E-AFEX™ processing technologies open up exciting new research avenues for cellulosic biorefineries, that allow selective conversion of the aromatic and carbohydrate fractions to a whole suite of fuels, materials and chemicals using desired catalytic or biocatalytic routes analogous to the petrochemical refineries.