A limiting key step in the biological conversion of biomass to biofuels and bioproducts is the efficient deconstruction and separation of targeted intermediates derived from the polysaccharides and lignin initially present. JBEI has established world-class and differentiated expertise in the use of ionic liquids (ILs) and deep eutectic solvents (DESs) as biomass pretreatment solvents that represent a potential game changing deconstruction technology, but there remain several significant scientific challenges that must be addressed before an affordable IL-based process is commercially viable. To address these challenges, we will discover and develop renewable ILs/DESs that are compatible with, or even improve the performance of, downstream enzymes and organisms, which in turn will enable process consolidation and intensification to minimize capital and operating expenses and increase yields.
Scientists in the Deconstruction Division will explore targeted microbial communities, with the ultimate goal of developing engineered microbial communities, organisms, pathways, and enzymes that enable efficient depolymerization of polysaccharides into monosaccharides and depolymerization and catabolism of lignin into intermediates that can be converted to biofuels and bioproducts. We will work to further improve enzymatic saccharification and lignin depolymerization by engineering enzymes not only to tolerate the presence of ILs/DESs but also to leverage that environment to improve enzyme activity while maintaining stability and activity in the presence of those ILs/DESs. The deployment of advanced enzyme mixtures tuned to the depolymerization of IL/DES pretreated biomass will require the development of hosts capable of producing high titers of these enzymes. We have demonstrated that fungi, such as Aspergillus niger, are suitable hosts for this task. The fungal strains will be modified by stacking of traits to continually improve enzyme production, and we will continue to expand the synthetic biology tools available to improve A. niger protein production.
The Deconstruction Division works closely with the other JBEI Divisions in order to provide the fundamental breakthroughs needed to establish a complete integrated solution for the production of targeted intermediates and products from sustainable lignocellulosic feedstocks.
Research Challenges
- Feedstock agnostic pretreatments that enable atom-economical valorization of the majority of the carbon present in the plant cell wall do not currently exist
- Lignin is a complex heterogeneous polymer and no robust and cost-effective method, biological or chemical, for its deconstruction into targeted intermediates exists
- Developing and optimizing a lignocelluloytic enzyme mixture capable of liberating fermentable sugars and lignin monomers at industrially relevant process conditions
- Enzymes that depolymerize polysaccharides and lignin into intermediates suitable for bioconversion remain complex, costly and difficult to express at high titers in recombinant hosts
- The discovery of inexpensive ionic liquids that are compatible with, or improve the performance of, enzymes and biofuel and bioproduct microbial hosts and can be efficiently recycled
Research Goals
- Develop and demonstrate affordable and scalable deconstruction with >90% yields of all major intermediates suitable for bioconversion
- Achieve 90% yields of lignin depolymerization into targeted intermediates suitable for bioconversion
- Engineer fungal strains that deconstruct biomass and generate 10 g/L of targeted bioproducts
