Lignin fate and characterization during ionic liquid biomass pretreatment for renewable chemicals and fuels production

Sathitsuksanoh, Noppadon; Holtman, Kevin M.; Yelle, Daniel J.; Morgan, Trevor; Stavila, Vitalie; Pelton, Jeffrey G.; Blanch, Harvey W.; Simmons, Blake A.; George, Anthe

doi:10.1039/c3gc42295j

Cited by 140 publications

(87 citation statements)

References 42 publications

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“…Plant cell wall samples from passage 4 replicates were extracted with water-ethanol and ball milled as previously described (20,21). Gels were formed using dimethyl sulfoxide d 6 (DMSO-d 6 ) and 1-ethyl-3-methylimidazolium acetate as a cosolvent (22,23) and homogenized by sonication in a Branson 2510 tabletop cleaner (Branson Ultrasonic Corporation, Danbury, CT). The temperature of the bath was closely monitored and maintained below 55°C.…”

Section: Methodsmentioning

confidence: 99%

Substrate-Specific Development of Thermophilic Bacterial Consortia by Using Chemically Pretreated Switchgrass

Eichorst

Joshua

Sathitsuksanoh

et al. 2014

Appl Environ Microbiol

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e Microbial communities that deconstruct plant biomass have broad relevance in biofuel production and global carbon cycling. Biomass pretreatments reduce plant biomass recalcitrance for increased efficiency of enzymatic hydrolysis. We exploited these chemical pretreatments to study how thermophilic bacterial consortia adapt to deconstruct switchgrass (SG) biomass of various compositions. Microbial communities were adapted to untreated, ammonium fiber expansion (AFEX)-pretreated, and ionicliquid (IL)-pretreated SG under aerobic, thermophilic conditions using green waste compost as the inoculum to study biomass deconstruction by microbial consortia. After microbial cultivation, gravimetric analysis of the residual biomass demonstrated that both AFEX and IL pretreatment enhanced the deconstruction of the SG biomass approximately 2-fold. Two-dimensional nuclear magnetic resonance (2D-NMR) experiments and acetyl bromide-reactive-lignin analysis indicated that polysaccharide hydrolysis was the dominant process occurring during microbial biomass deconstruction, and lignin remaining in the residual biomass was largely unmodified. Small-subunit (SSU) rRNA gene amplicon libraries revealed that although the dominant taxa across these chemical pretreatments were consistently represented by members of the Firmicutes, the Bacteroidetes, and Deinococcus-Thermus, the abundance of selected operational taxonomic units (OTUs) varied, suggesting adaptations to the different substrates. Combining the observations of differences in the community structure and the chemical and physical structure of the biomass, we hypothesize specific roles for individual community members in biomass deconstruction.

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Section: Methodsmentioning

confidence: 99%

Substrate-Specific Development of Thermophilic Bacterial Consortia by Using Chemically Pretreated Switchgrass

Eichorst

Joshua

Sathitsuksanoh

et al. 2014

Appl Environ Microbiol

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“…All of the ILs were tested as mixtures in 20% water and compared with untreated biomass and the effect of the benchmark ionic liquid [C 2 C 1 im][OAc], also containing 20% water. 16 The carbohydrate composition of biomass and residual biomass after hydrolysis was determined with a modified quantitative saccharification (QS) procedure. 17 The standard NREL biomass protocol was used to measure lignin and ash 18 .…”

Section: Il Design Rationalementioning

confidence: 99%

Design of low-cost ionic liquids for lignocellulosic biomass pretreatment

et al. 2015

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The cost of ionic liquids (IL) is one of the main impediments to IL utilization in the cellulosic biorefinery, especially in the pretreatment step. In this study, a number of ionic liquids were synthesized with the goal of optimizing solvent cost and stability whilst demonstrating promising processing potential. To achieve this, inexpensive feedstocks such as sulfuric acid and simple amines were combined into a range of protic ionic liquids containing the hydrogen sulfate [HSO 4 ] -anion. The performance of these ionic liquids was compared to a benchmark system containing the IL 1-ethyl-3-methylimidazolium acetate [C 2 C 1 im][OAc]. The highest saccharification yields were observed for the triethylammonium hydrogen sulfate IL, which was 75% as effective as the benchmark system. Techno-economic modeling revealed that this promising and yet to be optimized yield was achieved at a fraction of the processing cost. This study demonstrates that some ILs can compete with the cheapest pretreatment chemicals, such as ammonia, in terms of effectiveness and process cost, removing IL cost as a barrier to the economic viability of IL-based biorefineries.

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“…Online resource 3 shows the FTIR spectra for samples before and after enzymatic hydrolysis. The lignin remaining after hydrolysis is expected to be higher molecular weight than that solubilized by IL pretreatment because lower molecular weight lignin is more easily solubilized [21]. Little difference can be seen between spectra of raw loblolly pine or glycerol pretreated pine and their respective hydrolyzed residues, as expected.…”

Section: Ftir Analysis After Hydrolysismentioning

confidence: 65%

Loblolly pine pretreatment by ionic liquid-glycerol mixtures

Lynam

Coronella

2015

Biomass Conv. Bioref.

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Glycerol was used as a cosolvent with the two ionic l i q u i d s 1 -e t h y l -3 -m e t h y l i m i d a z o l i u m f o r m a t e ([C2mim][O2CH]) and 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) to pretreat loblolly pine at 140°C. Enzymatic hydrolysis was then performed on raw and pretreated pines to establish pretreatment efficacy. With pretreatment, glucose yield from enzymatic hydrolysis was improved from 2 % for raw pine up to 43 %, while yields of mannose/xylose combined improved from 4 % up to 77 %. Pine pretreated with a 50 % [C2mim][O2CH]-50 % glycerol mixture exhibited a pulp-like structure, likely formed from removal of the lignin that binds cell walls together. Using this 50 % mixture of [C2mim][O2CH] and glycerol for pretreatment gave a slightly lower glucose yield than a 75 % mixture of [C2mim][O2CH] and glycerol but gave a mannose/xylose yield twice as high. Klason lignin and Fourier transform infrared spectroscopy (FTIR) analysis indicated that [C2mim][O2CH]-glycerol pretreatment preferentially dissolves lignin. FTIR analysis also suggested increased amorphous cellulose content with this pretreatment. Using the anti-solvent ethanol, a lignin-rich substance was precipitated from the solvent mixtures.

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Lignin fate and characterization during ionic liquid biomass pretreatment for renewable chemicals and fuels production

Abstract: The fate of lignin from wheat straw, Miscanthus, and Loblolly pine after pretreatment by a non-toxic and recyclable ionic liquid (IL), [C2mim][OAc], followed by enzymatic hydrolysis was investigated.

Cited by 140 publications

References 42 publications

Substrate-Specific Development of Thermophilic Bacterial Consortia by Using Chemically Pretreated Switchgrass

Substrate-Specific Development of Thermophilic Bacterial Consortia by Using Chemically Pretreated Switchgrass

Design of low-cost ionic liquids for lignocellulosic biomass pretreatment

Loblolly pine pretreatment by ionic liquid-glycerol mixtures

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