Dissolution of cellulose with ionic liquid in pressurized cell

Dissolution of cellulose in imidazolium-based double salt ionic liquids

The dissolution of cellulose in double salt ionic liquids (DSILs) was studied in detail and compared with the dissolution in individual constituent ionic liquids (ILs). The DSILs, [C4mim](CH3CO2)xCl1-x (x is the mole fraction of the single component ILs), were synthesized using acetate and chloride salts of 1-butyl-3-methylimidazolium. These DSILs were then used for the investigation of the solubility of cellulose in the whole mole fraction range. Commercial cellulose (CC) powder, kraft pulp (KP), and prehydrolysis kraft pulp (PHKP) of jute were chosen as cellulose sources. The solubility of cellulose increased with an increasing temperature for [C4mim](CH3CO2)0.6Cl0.4 and with increasing amount of [C4mim]Cl in DSILs. The maximum solubility of CC powder was 32.8 wt% in [C4mim](CH3CO2)0.6Cl0.4 at 100 °C, while for KP and PHKP, solubilities were 30.1 and 30.5 wt%, respectively under the identical condition. Cellulose could be regenerated from the DSILs using water as an antisolvent. Structure, morphology, and thermal stability of the regenerated cellulosic materials were analyzed. DSILs could be recycled >99 % without a discernible change in structure. This work demonstrates that DSILs display enhanced solubility over ILs system and have potential as a chemical processing methodology.

Revolutionizing lignocellulosic biomass: A review of harnessing the power of ionic liquids for sustainable utilization and extraction

The potential for the transformation of lignocellulosic biomass into valuable commodities is rapidly growing through an environmentally sustainable approach to harness its abundance, cost-effectiveness, biodegradability, and environmentally friendly nature. Ionic liquids (ILs) have received considerable and widespread attention as a promising solution for efficiently dissolving lignocellulosic biomass. The fact that ILs can act as solvents and reagents contributes to their widespread recognition. In particular, ILs are desirable because they are inert, non-toxic, non-flammable, miscible in water, recyclable, thermally and chemically stable, and have low melting points and outstanding ionic conductivity. With these characteristics, ILs can serve as a reliable replacement for traditional biomass conversion methods in various applications. Thus, this comprehensive analysis explores the conversion of lignocellulosic biomass using ILs, focusing on main components such as cellulose, hemicellulose, and lignin. In addition, the effect of multiple parameters on the separation of lignocellulosic biomass using ILs is discussed to emphasize their potential to produce high-value products from this abundant and renewable resource. This work contributes to the advancement of green technologies, offering a promising avenue for the future of biomass conversion and sustainable resource management.

Dissolution performance of cellulose in [A2im][MOA]/MIM solvents

Cellulose solvents ([A2im][MOA]/MIM) were developed by combining diallylimidazolium methoxyacetate ([A2im][MOA]) with N-methylimidazole (MIM). The cellulose solubilities in the ([A2im][MOA]/MIM) solvents were determined at 25 °C, and the effect of the MIM/[A2im][MOA] molar ratio on cellulose solubility was systematically investigated. Attractively, the solvents show cellulose solubility as high as 25.2 g 100 g-1 even at 25 °C. It is proposed that the H2, H4 and H6 in [A2im]+ and the carboxyl O atom in [MOA]- primarily contribute to the dissolution of cellulose; MIM mainly acts to dissociate [A2im][MOA] into [A2im]+ and [MOA]-, and stabilize the dissolved cellulose chains. Moreover, the porous cellulose materials with varying morphological structures could be tailored by simply tuning the cellulose solution concentration, and the formation mechanism of the cellulose material was discussed.

Co-immobilization of laccase and ABTS onto novel dual-functionalized cellulose beads for highly improved biodegradation of indole

The method developed in this work, for the first time, for the co-immobilization of mediator 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and laccase, in which the dual-functionalized cellulose beads with network pore structure were constructed by polydopamine (PD) and polymeric glycidyl methacrylate (GMA) to obtain the biocatalyst co-immobilizing ABTS and laccase. ABTS molecules were encapsulated into the dual-functionalized cellulose beads to obtain an efficient carrier (PD-GMA-Ce/ABTS) on which the laccase could be covalently immobilized by means of the coupling between the amino groups of the enzyme and the epoxy groups and ortho-dihydroxyphenyl groups existing on the beads. The as-prepared PD-GMA-Ce/ABTS with network pore structure were characterized by SEM, XRD, FT-IR and EPR. The resultant beaded biocatalyst (PD-GMA-Ce/ABTS@Lac) co-immobilizing laccase and ABTS were used in the biodegradation of indole and the degradation rate was up to 99.7%, while indole is difficult to be degraded by free laccase. The PD-GMA-Ce/ABTS@Lac beads displayed considerably reusability and storage stability for indole degradation after cycling of 10 runs or storage of 100 days benefited from the mediation effect of the immobilized ABTS. The effective recovery of both expensive laccase and hazardous ABTS by using PD-GMA-Ce/ABTS@Lac is promising to reduce the cost for the laccase application in wastewater treatment and might be helpful to eliminate the secondary pollution from the free mediator.

Impact of lignin polymer backbone esters on ionic liquid pretreatment of poplar

BACKGROUND

Biomass pretreatment remains an essential step in lignocellulosic biofuel production, largely to facilitate the efficient removal of lignin and increase enzyme accessibility to the polysaccharides. In recent years, there have been significant efforts in planta to reduce lignin content or modify its composition to overcome the inherent recalcitrance that it imposes on lignocellulosic biomass during processing. Here, transgenic poplar lines in which monolignol ferulate conjugates were synthesized during cell wall development to introduce, during lignification, readily cleavable ester linkages into the lignin polymer backbone (i.e., "zip lignin"), along with wild-type (WT) controls, were pretreated with different ionic liquids (ILs).

RESULTS

The strategic introduction of ester bonds into the lignin backbone resulted in increased pretreatment efficiency and released more carbohydrates with lower energy input. After pretreatment with any of three different ILs, and after limited saccharification, the transgenic poplars, especially those with relatively higher amounts of incorporated monolignol ferulate conjugates, yielded up to 23% higher sugar levels compared to WT plants.

CONCLUSION

Our findings clearly demonstrate that the introduction of ester linkages into the lignin polymer backbone decreases biomass recalcitrance in poplar has the potential to reduce the energy and/or amount of IL required for effective pretreatment, and could enable the development of an economically viable and sustainable biorefinery process.

Recent advances in exploiting ionic liquids for biomolecules: Solubility, stability and applications

The technological utility of biomolecules (e.g. proteins, enzymes and DNA) can be significantly enhanced by combining them with ionic liquids (ILs) - potentially attractive "green" and "designer" solvents - rather than using in conventional organic solvents or water. In recent years, ILs have been used as solvents, cosolvents, and reagents for biocatalysis, biotransformation, protein preservation and stabilization, DNA solubilization and stabilization, and other biomolecule-based applications. Using ILs can dramatically enhance the structural and chemical stability of proteins, DNA, and enzymes. This article reviews the recent technological developments of ILs in protein-, enzyme-, and DNA-based applications. We discuss the different routes to increase biomolecule stability and activity in ILs, and the design of biomolecule-friendly ILs that can dissolve biomolecules with minimum alteration to their structure. This information will be helpful to design IL-based processes in biotechnology and the biological sciences that can serve as novel and selective processes for enzymatic reactions, protein and DNA stability, and other biomolecule-based applications.

Ionic liquids as a potential tool for drug delivery systems

The pharmaceutical industries face a series of challenges in the delivery of many newly developed drug molecules because of their low solubility, bioavailability, stability and polymorphic conversion.

Ionic liquid-mediated transcutaneous protein delivery with solid-in-oil nanodispersions

We report a novel ionic liquid (IL)-mediated transcutaneous vaccine formulation consisting of a solid-in-oil nanodispersion of antigen coated with pharmaceutically accepted surfactants dispersed in IL-containing oil. The introduction of IL in the formulation significantly enhanced the skin permeability of ovalbumin, a model antigen.