Developing Ionic-Liquid Tolerant Enzymatic Cocktails for Lignocellulosic Biomass Deconstruction
EMSL Project ID
47499
Abstract
The DOE Joint BioEnergy Institute (JBEI) is tasked with developing these advanced biofuels from lignocellulosic biomass. Part of this mission is to develop efficient methods to deconstruct biomass, by both gaining a more in-depth understanding of biomass degrading microbial communities, and identifying and charactering novel lignocellulolytic microorganisms and enzymes. At JBEI, novel ionic liquid pretreatment processes have been developed that have the promise of generating monomeric sugars from biomass with low enzyme loadings, high polysaccharide conversions and isolation of a separate stream of lignin for further processing. However, residual ionic liquid from the pretreatment inhibits commercial fungal enyzmes used for polysaccharide hydrolysis.
Work at JBEI has demonstrated that thermophilic and halophilic bacterial glycoside hydrolases retain activity in the presence of high levels of ionic liquids. A catalog of thermophilic glycoside hydrolases compatible with ionic liquids has been compiled using known enzymes and enzymes derived from thermophilic enrichments. A comparable catalog is lacking for halophilic enzymes, so characterizing glycoside hydrolases from high-salt environments will provide enzymes to compose a halophilic, ionic-liquid tolerant cocktail. Protein expression levels of these enzymes in microbial hosts (E.coli, H. volcanii) is low. Developing new fungal protein expression hosts to express these enzymes at high titer will allow us to scale the production of tailored enzymatic cocktails for biomass deconstruction.
Modification and depolymerization of lignin is critical to increasing availability of plant polysaccharides for hydrolysis to monomeric sugars. Additionally, ionic-liquid pretreatment can produce a soluble lignin-rich stream that requires depolymerization to recycle the ionic liquid. Lignin depolymerization has only been studied extensively in basidiomycete fungi. Evidence obtained at JBEI suggests that both bacterial consortia and ascomycete fungi modify lignin and solubilize lignin oligomers.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2012-10-01
End Date
2013-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
D'haeseleer P, JM Gladden, M Allgaier, P Chain, SG Tringe, S Malfatti, JT Aldrich, CD Nicora, EW Robinson, L Pasa-Tolic, P Hugenholtz, BA Simmons, and SW Singer. 2013. "Proteogenomic Analysis of a Thermophilic Bacterial Consortium Adapted to Deconstruct Switchgrass." PLoS One 8(7):e68465. doi:10.1371/journal.pone.0068465