(86d) Ionic Liquids Based Consolidated Bioprocessing for Biofuel Production from Lignocellulosic Biomass

Jian Sun, NVSN M. Konda, Tanmoy Dutta, Blake Simmons, Seema Singh

Deconstruction Division, Joint BioEnergy Institute, Emeryville, CA, USA

Biological and Engineering Sciences Center, Sandia National Laboratories, Livermore, CA, USA

Abstract

Lignocelluloses are rich sugar precursors, which can be converted to biofuels with the help of efficient combination of enzymes and microbes. Pretreatment technologies aiming to increase fermentable sugar yields by overcoming recalcitrance of lignocellulosic biomass is highly essential. The use of ionic liquids (ILs) in biomass pretreatment has received considerable attention recently because of their effectiveness at decreasing biomass recalcitrance to subsequent enzymatic hydrolysis. There is a clear and unmet need for a consolidated bioprocessing technology that can process a wide-range of sustainable feedstocks and produce high yields of fermentable sugars and biofuels with minimal intervention between unit operations. However, the integration of IL based pretreatment with enzymatic saccharification and microbial fermentation is highly challenging due to the toxicity of the ILs as well as high pH issue currently used for pretreatment, requiring extensive water washes, pH adjustment or the development of engineered IL tolerant enzymes and microbes.

Herein, an integrated one-pot biomass conversion technology has been developed, for the first time, using cholinium based ionic liquids (ILs) for advanced fuel production. The process integration eliminates the need for separation and purification after biomass pretreatment, which simplifies the conversion process and reduces the operating costs. The used renewable ILs have been tested in terms of pretreatment efficiency and the compatibility with enzymes and microorganisms. Significant progress has been made to enhance the process efficiency, lower the water usage, and increase the fuel titer by using high-gravity fed-batch operations.¹ An innovative strategy using CO₂ as a reversible method of controlling pH was developed to avoid the addition of extra chemicals thus making the recycle of IL much easier and viable.² A preliminary technoeconomic analysis indicates that the above integrated approach could reduce production costs by 40–65% compared to previous IL biomass conversion methods studied. The established approaches indicate that a consolidated process for the biofuel production from biomass that eliminates the need for intermediate washing and/or separation steps can be enabled by ionic liquids.

References

1. F. Xu, J. Sun, N. V. S. N. M. Konda, J. Shi, T. Dutta, C. D. Scown, B. A. Simmons, S. Singh, Energy Environ. Sci., 2016, 9, 1042-1049

1. J. Sun, N. V. S. N. M. Konda, J. Shi, R. Parthasarathi, T. Dutta, F. Xu, C. D. Scown, B. A. Simmons, S. Singh, Energy Environ. Sci., 2016, 9, 2822-2834.