A facile pretreatment strategy for recovering sugars and lignin effectively from a variety of lignocellulosic feedstocks

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0933250VaranasiSummary Intellectual Merits: Plant biomass can provide a sustainable feedstock for future "biorefineries" partially replacing conventional petrochemical refineries. The PI plans to capitalize on the solvation properties of ionic liquids (ILs) to overcome the recalcitrance of cellulose and biomass to enzymatic hydrolysis, a core barrier to economical and sustainable biofuels production. The hydrolyzate can be used as a fermentation feedstock for ethanol production or as a sugar platform for production of other chemicals. With the proper selection of enzymes, initial rates of hydrolysis for IL treated pure cellulose are nearly 2 orders of magnitude greater than those of untreated cellulose. Conversion of cellulose in biomass is also substantially accelerated in comparison to alternative pretreatment methods. The proposed research seeks to systemically assess and optimize the pretreatment process applied to biomass with the aim of minimizing chemical and energy inputs. To achieve this, a clear understanding of the structural and chemical changes in biomass with ionic liquid pretreatment and the effects of those changes on subsequent hydrolysis is needed. The following specific objectives will be addressed to achieve this end:(1) Assess fundamental factors which affect kinetics and product yield for biomass saccharification to optimize pretreatment. (2) Engineer the hydrolyzing enzyme mixture to optimize hexose and pentose sugar yields from IL-pretreated biomass. (3) Recover and recycle saccharification enzymes and ionic liquids and assess unhydrolyzed portions of biomass for lignin recovery. Broader impacts: Ionic liquids have the potential to convert wood and grasses into viable feedstocks for fuel and chemical production. Ionic liquids have no measurable vapor pressure and are considered green due to their negligible impact on air quality. An essential part of this project is the training and educating of graduate and undergraduate students, who will obtain considerable experience in biochemical methods, analytical techniques, ionic liquid synthesis, characterization, and assessment of chemical and structural changes in lignocellulosic materials, a very complex system. The interdisciplinary nature of this project will allow graduate and undergraduate researchers to acquire a broad-based training. Demonstration modules and background material will be developed in biofuels for integration into UTube, a site spear-headed by our collaborator Dr. Jared Anderson. The site will contain links to a series of video demonstrations performed by the co-investigators and undergraduate researchers tailored to middle school children. The PI and Co-PI's have served as high school and undergraduate student research mentors. One has participated in the NSF Young Scholars program, to introduce economically disadvantaged students to engineering. The other has been involved in outreach activities as the faculty advisor to the Society of Woman Engineers and through involvement in the GEARUP and EXCEL programs sponsored by the US Department of Education to introduce African American and Latino middle and high school students to hands-on engineering projects.