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Biofilm formation on the membrane surface results in the loss of permeability in membrane bioreactors (MBRs) for wastewater treatment. Studies have revealed that cellulose is not only produced by a number of bacterial species but also plays a key role during formation of their biofilm. Hence, in this study, cellulase was introduced to a MBR as a cellulose-induced biofilm control strategy. For practical application of cellulase to MBR, a cellulolytic ( i.e ., cellulase-producing) bacterium, Undibacterium sp. DM-1, was isolated from a lab-scale MBR for wastewater treatment. Prior to its application to MBR, it was confirmed that the cell-free supernatant of DM-1 was capable of inhibiting biofilm formation and of detaching the mature biofilm of activated sludge and cellulose-producing bacteria. This suggested that cellulase could be an effective anti-biofouling agent for MBRs used in wastewater treatment. Undibacterium sp. DM-1-entrapping beads ( i.e ., cellulolytic-beads) were applied to a continuous MBR to mitigate membrane biofouling 2.2-fold, compared with an MBR with vacant-beads as a control. Subsequent analysis of the cellulose content in the biofilm formed on the membrane surface revealed that this mitigation was associated with an approximately 30% reduction in cellulose by cellulolytic-beads in MBR.

Alginate/bacterial cellulose nanocomposite beads, with well-controlled size and regular spherical shapes, were prepared in a simple manner by entrapping Gluconacetobacter xylinus in barium alginate hydrogel beads, followed by cultivation of the entrapped cells in culture media with a low sodium ion concentration. The entire surface of the alginate hydrogel beads containing the cells was covered with cellulose fibers (∼30nm) after 36h of cultivation. The cellulose crystallinity index of the alginate/bacterial cellulose beads was 0.7, which was slightly lower than that of bacterial cellulose prepared by cultivating dispersed cells. The water vapor sorption capacity of the alginate/bacterial cellulose beads increased significantly from 0.07 to 38.00 (g/g dry bead) as cultivation time increased. These results clearly indicate that alginate/bacterial cellulose beads have a much higher surface area, crystallinity, and water-holding capacity than alginate beads. The immobilization of lipase on the surface of the nanocomposite beads was also investigated as a potential application of this system. The activity and specific activity of lipase immobilized on alginate/bacterial cellulose beads were 2.6- and 3.8-fold higher, respectively, than that of lipase immobilized on cellulose beads. The alginate/bacterial cellulose nanocomposite beads prepared in this study have several potential applications in the biocatalytic, biomedical, and pharmaceutical fields because of their biocompatibility, biodegradability, high crystallinity, and large surface area., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Biofuel cells are devices for generating electrical energy directly from chemical energy of renewable biomass using biocatalysts such as enzymes. Efficient electrical communication between redox enzymes and electrodes is essential for enzymatic biofuel cells. Carbon nanotubes (CNTs) have been recognized as ideal electrode materials because of their high electrical conductivity, large surface area, and inertness. Electrodes consisting entirely of CNTs, which are known as CNT paper, have high surface areas but are typically weak in mechanical strength. In this study, cellulose (CL)-CNT composite paper was fabricated as electrodes for enzymatic biofuel cells. This composite electrode was prepared by vacuum filtration of CNTs followed by reconstitution of cellulose dissolved in ionic liquid, 1-ethyl-3-methylimidazolium acetate. Glucose oxidase (GOx), which is a redox enzyme capable of oxidizing glucose as a renewable fuel using oxygen, was immobilized on the CL-CNT composite paper. Cyclic voltammograms revealed that the GOx/CL-CNT paper electrode showed a pair of well-defined peaks, which agreed well with that of FAD/FADH2, the redox center of GOx. This result clearly shows that the direct electron transfer (DET) between the GOx and the composite electrode was achieved. However, this DET was dependent on the type of CNTs. It was also found that the GOx immobilized on the composite electrode retained catalytic activity for the oxidation of glucose.

The effects of the type and the concentration of the co-solvent on the spinnability during cellulose electrospinning and the properties of the fiber were studied using cellulose dissolved in ionic liquid and co-solvent (DMF or DMAc). The prepared solution was electrospun onto a wired collector and coagulated in ethanol. As the weight ratio of co-solvent against ionic liquid increased, the spinnability was improved with stable whipping and splaying motion. Regardless of the co-solvent type, the higher co-solvent concentration resulted in finer fiber diameter, better web uniformity, higher crystallinity and better thermal stability. Comparing to DMAc, DMF showed more significant influence on the fiber diameter and the crystallinity., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Lignocellulose represents a key sustainable source of biomass for transformation into biofuels and bio-based products. Unfortunately, lignocellulosic biomass is highly recalcitrant to biotransformation, both microbial and enzymatic, which limits its use and prevents economically viable conversion into value-added products. As a result, effective pretreatment strategies are necessary, which invariably involves high energy processing or results in the degradation of key components of lignocellulose. In this work, the ionic liquid, 1-ethyl-3-methylimidazolium acetate ([Emim][CH3COO]), was used as a pretreatment solvent to extract lignin from wood flour. The cellulose in the pretreated wood flour becomes far less crystalline without undergoing solubilization. When 40% of the lignin was removed, the cellulose crystallinity index dropped below 45, resulting in > 90% of the cellulose in wood flour to be hydrolyzed by Trichoderma viride cellulase. [Emim] [CH3COO] was easily reused, thereby resulting in a highly concentrated solution of chemically unmodified lignin, which may serve as a valuable source of a polyaromatic material as a value-added product.

We report novel heparin-cellulose-charcoal composites prepared using room temperature ionic liquids (RTILs) to enhance the biocompatibility and blood compatibility of activated charcoal beads while decreasing the size of their active pores.

In this study, cellulose/Fe3O4 hydrogel microbeads were prepared through the sol–gel transition of a solvent-in-oil emulsion using various cellulose-dissolving solvents and soybean oil without surfactants. Particularly, 40% tetrabutylammonium hydroxide (TBAH) and 40% tetrabutylphosphonium hydroxide (TBPH) dissolved cellulose at room temperature and effectively dispersed Fe3O4, forming cellulose/Fe3O4 microbeads with an average diameter of ~15 µm. Additionally, these solvents co-dissolved cellulose and silk, allowing for the manufacture of cellulose/silk/Fe3O4 hydrogel microbeads with altered surface characteristics. Owing to the negatively charged surface characteristics, the adsorption capacity of the cellulose/silk/Fe3O4 microbeads for the cationic dye crystal violet was >10 times higher than that of the cellulose/Fe3O4 microbeads. When prepared with TBAH, the initial adsorption rate of bovine serum albumin (BSA) on the cellulose/silk/Fe3O4 microbeads was 18.1 times higher than that on the cellulose/Fe3O4 microbeads. When preparing TBPH, the equilibrium adsorption capacity of the cellulose/silk/Fe3O4 microbeads for BSA (1.6 g/g) was 8.5 times higher than that of the cellulose/Fe3O4 microbeads. The pH-dependent BSA release from the cellulose/silk/Fe3O4 microbeads prepared with TBPH revealed 6.1-fold slower initial desorption rates and 5.2-fold lower desorption amounts at pH 2.2 than those at pH 7.4. Cytotoxicity tests on the cellulose and cellulose/silk composites regenerated with TBAH and TBPH yielded nontoxic results. Therefore, cellulose/silk/Fe3O4 microbeads are considered suitable pH-responsive supports for orally administered protein pharmaceuticals. [ABSTRACT FROM AUTHOR]

ABSTRACT Artificial wood films containing cellulose, xylan, and lignin were easily prepared by the dissolution of wood components in 1-ethyl-3-methylimidazolium acetate followed by reconstitution with distilled water. The composition and characteristics of wood films were highly controllable and predictable through the variation of the concentration of each component in the wood solution. The water vapor solubility of the wood films was increased when the xylan content was increased and the content of lignin was decreased. The biodegradability of the artificial wood films was investigated with cellulase from Trichoderma viride. The relative degradability of the wood film prepared with 5% cellulose and 5% lignin was 42%, whereas that of the wood film made with 5% cellulose and 5% xylan was 189%. The biodegradability of cellulose in the wood films correlated well with the content of xylan and lignin, and it was enhanced when the xylan content was increased and the content of lignin was decreased. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42109. [ABSTRACT FROM AUTHOR]

Abstract: Nanoscale fiber was successfully electrospun from lignocellulosic biomass (hemp) dissolved by IL (1-ethyl-3-methylimiazolium acetate [C2min][OAc]). The biomass was treated by alkalis, NaOH and NaClO2 for different time to reduce the lignin content. For better spinnability, excess DMF was added to the spinning dope. When the residual lignin content was higher than 6%, the solution was sprayed into mist type droplets or formed large drops at the end of the nozzle without forming stable jet. The further reduction of the lignin resulted in more stable jet and better spinnability as well as smaller and uniform fiber diameter. [Copyright &y& Elsevier]

Cellulose hydrogels are considered useful biocompatible and biodegradable materials. However, as few cellulose-dissolving solvents can be used to prepare cellulose hydrogel microspheres, the use of unmodified cellulose-based hydrogel microspheres for enzyme immobilization remains limited. Here, we prepared cellulose/Fe2O3 hydrogel microspheres as enzyme supports through sol-gel transition using a solvent-in-oil emulsion. Cellulose-dissolving solvents including 1-ethyl-3-methylimidazolium ([Emim][Ac]), an aqueous mixture of NaOH and thiourea, tetrabutylammonium hydroxide, and tetrabutylphosphonium hydroxide were used to prepare regular shaped cellulose/Fe2O3 microspheres. The solvent affected microsphere characteristics like crystallinity, hydrophobicity, surface morphology, size distribution, and swelling properties. The immobilization efficiency of the microspheres for lipase was also significantly influenced by the type of cellulose solvent used. In particular, the lipase immobilized on cellulose/Fe2O3 microspheres prepared using [Emim][Ac] showed the highest protein loading, and its specific activity was 3.1-fold higher than that of free lipase. The immobilized lipase could be simply recovered by a magnet and continuously reused. [ABSTRACT FROM AUTHOR]

Lignocellulose-based hydrogels may have many potential applications in biomedical and biotechnological fields owing to their attractive properties including low cost, biodegradability, and biocompatibility. In this study, cellulose/lignin composite hydrogel beads were prepared by co-dissolution of cellulose and lignin in 1-ethyl-3-methylimidazolium acetate and then reconstitution with distilled water. Lipase from Candida rugosa was immobilized on various cellulose/lignin hydrogel beads. The results showed that lipase immobilized on cellulose/lignin beads showed higher activity and stability than those of lipase immobilized on pure cellulose beads. The activity and stability of immobilized lipase increased with the increase in the lignin content in the cellulose/lignin beads. The activity, protein loading, and specific activity of lipase immobilized on the optimal cellulose/lignin beads were 2.6, 2.2, and 1.2 times higher than those of lipase immobilized on cellulose beads, respectively. The effect of lignin on the activity of lipase immobilized on cellulose/lignin beads was statistically well predicted. The residual activity of lipase immobilized on the optimal cellulose/lignin beads after incubation for 12 h at 40 °C was 3.2 and 1.9 times higher than that of free lipase and lipase immobilized on cellulose beads, respectively. Interestingly, the half-life time of lipase immobilized on cellulose/lignin beads at pH 3.0 was 24 and 3 times higher than that of free lipase and that of lipase immobilized on cellulose beads, respectively. These results show that cellulose/lignin hydrogels may offer many potential applications in the biocatalytic, biomedical, and bioelectronic fields owing to their high biocompatibility, biodegradability, and controllable properties. [ABSTRACT FROM AUTHOR]

Abstract: For the first time, lipase from Candida rugosa was successfully entrapped into various cellulose–biopolymer composite hydrogels by using a biocompatible ionic liquid, 1-ethyl-3-methylimidazolium acetate ([Emim][Ac]). Lipase-entrapped cellulose and cellulose–biopolymer composite hydrogel beads were simply prepared by co-dissolution of biopolymers in [Emim][Ac] and dispersion of lipase in biopolymer solution followed by formation of biopolymer hydrogel using distilled water. Immobilization yields (specific activity ratio of entrapped lipase to free lipase) of cellulose, cellulose–carrageenan, cellulose–chitosan, cellulose–agarose, and cellulose–agar bead were 35.0, 9.6, 39.7, 41.4, and 52.6%, respectively. Cellulose–biopolymer composite hydrogels proved to be good supports for entrapment of enzymes and have many potential applications, including drug delivery, biosensors, biofuel cells, and tissue engineering due to their inherent excellent biocompatibility and biodegradability. [Copyright &y& Elsevier]