Electrically conducting films prepared from graphite and lignin in pure water.

In this study, we present electrically conducting self-standing graphite films consisting of lignin derivatives extracted by simultaneous enzymatic saccharification and comminution (SESC). Sonication of graphite powder in the presence of SESC lignin and pure water allows dispersion of the SESC-lignin-attached graphite without addition of other chemicals. The SESC-lignin-attached graphite having a diameter of several micrometers can be used as a surface electroconductive coating and molded into self-standing films by drying. The SESC-lignin-attached graphite film exhibits higher conductivity (∼2,075 S/cm) than graphite-based composites consisting of ordinary lignin derivatives. Manufacturing self-standing films of micrometer-sized graphite using SESC lignin enables high electrical conductivity of the SESC-lignin-attached graphite film. The size of the SESC-lignin-attached graphite is proportional to the conductivity of the film. The SESC-lignin-attached graphite also acts as an antiplasticizer and a conductive filler for polymer films, i.e., conductive films consisting of poly(ethylene glycol) or Li+ montmorillonite can be obtained through a water-based process.

Spontaneous Alignment of Microtubules Via Tubulin Polymerization in a Narrow Space Under a Temperature Gradient.

In this chapter, protocols for spontaneous alignment of microtubules (MTs), such as helices and spherulites, via tubulin polymerization in a narrow space and under a temperature gradient are presented for tubulin solutions and tubulin-polymer mixtures. These protocols provide an easy route for hierarchical MT assembly and may extend our current understanding of cytoskeletal protein self-assembly under dissipative conditions.

Correction: Enhanced ionic conduction in composite polymer electrolytes filled with plant biomass "lignin".

Correction for 'Enhanced ionic conduction in composite polymer electrolytes filled with plant biomass "lignin"' by Zitong Liu et al., Chem. Commun., 2022, DOI: 10.1039/d1cc07148c.

Enhanced ionic conduction in composite polymer electrolytes filled with plant biomass "lignin".

The addition of a small amount of plant biomass-based lignin causes a large improvement in the ionic conductivity of composite polymer electrolytes at room temperature, which can be fabricated easily in a low carbon way for use in future all-solid-state battery applications.

Nonflammable UV protective films consisting of clay and lignin with tunable light/gas transparency.

In this paper, we present nonflammable UV protective films consisting of clay minerals and lignin derivatives. The nonflammable transparent films were produced by mixing clay with a lignin derivative extracted from plants by simultaneous enzymatic saccharification and comminution. The preparation procedure did not require hazardous chemicals. The optical properties and gas permeability of the films could be tuned by the components and phase separation structure of the clay minerals and lignin derivatives. In particular, the gas transmittance of the films could be controlled in the range of several mol m-2 s-1 Pa-1. The present film uses mineral and plant components as high-value industrial materials and reduces the environmental load of extracting limited petroleum-based resources.

Radial alignment of microtubules through tubulin polymerization in an evaporating droplet.

We report the formation of spherulites from droplets of highly concentrated tubulin solution via nucleation and subsequent polymerization to microtubules (MTs) under water evaporation by heating. Radial alignment of MTs in the spherulites was confirmed by the optical properties of the spherulites observed using polarized optical microscopy and fluorescence microscopy. Temperature and concentration of tubulins were found as important parameters to control the spherulite pattern formation of MTs where evaporation plays a significant role. The alignment of MTs was regulated reversibly by temperature induced polymerization and depolymerization of tubulins. The formation of the MTs patterns was also confirmed at the molecular level from the small angle X-ray measurements. This work provides a simple method for obtaining radially aligned arrays of MTs.

Solvent-Free Fabrication of an Elastomeric Epoxy Resin Using Glycol Lignin from Japanese Cedar.

In this study, a simple formulation of softwood-derived glycol lignin (GL)-based epoxy resin with a high GL content of greater than 50 wt % was demonstrated by direct mixing with poly(ethylene glycol) diglycidyl ether (PEGDGE), an aliphatic epoxide, without using any solvent. Because the GL powder produced from poly(ethylene glycol) (PEG400) solvolysis of Japanese cedar softwood meal was a PEG400-modified lignin (GL400), a strong affinity between PEG counterparts facilitates the uniform mixing of GL400 with PEGDGE, and one component uncured GL400/PEGDGE epoxy resin was prepared at a relatively lower temperature (100 °C) than the curing temperature (130 °C). The epoxy curing reaction was monitored by 1H NMR and Fourier transform infrared spectroscopies. The physical and mechanical properties of the epoxy resins with different GL400 contents were then evaluated. The developed resins exhibited good flexibility and elasticity depending on the GL400 content.

Liquid Crystalline Colloidal Mixture of Nanosheets and Rods with Dynamically Variable Length.

Here, we demonstrate the novel double-component liquid crystalline colloids composed of mesogenic inorganic nanosheets and the rods with dynamically variable length controlled by temperature. As the length-controllable rod, stiff biopolymer microtubule is used, which was successfully polymerized/depolymerized from tubulin proteins through a biochemical process even in the presence of the nanosheets. The mesoscopic structure of the liquid crystal phase was reversibly modifiable as caused by the change of the rod length.

Simultaneous enzymatic saccharification and comminution for the valorization of lignocellulosic biomass toward natural products.

BACKGROUND: Large-scale processing of lignocellulosics for glucose production generally relies on high temperature and acidic or alkaline conditions. However, extreme conditions produce chemical contaminants that complicate downstream processing. A method that mainly rely on mechanical and enzymatic reaction completely averts such problem and generates unmodified lignin. Products from this process could find novel applications in the chemicals, feed and food industry. But a large-scale system suitable for this purpose is yet to be developed. In this study we applied simultaneous enzymatic saccharification and communition (SESC) for the pre-treatment of a representative lignocellulosic biomass, cedar softwood, under both laboratory and large-scale conditions. RESULTS: Laboratory-scale comminution achieved a maximum saccharification efficiency of 80% at the optimum pH of 6. It was possible to recycle the supernatant to concentrate the glucose without affecting the efficiency. During the direct alcohol fermentation of SESC slurry, a high yield of ethanol was attained. The mild reaction conditions prevented the generation of undesired chemical inhibitors. Large-scale SESC treatment using a commercial beads mill system achieved a saccharification efficiency of 60% at an energy consumption of 50 MJ/kg biomass. CONCLUSION: SESC is very promising for the mild and clean processing of lignocellulose to generate glucose and unmodified lignin in a large scale. Economic feasibility is highly dependent on its potential to generate high value natural products for energy, specialty chemicals, feed and food application.

Tuneable shape-memory properties of composites based on nanoparticulated plant biomass, lignin, and poly(ethylene carbonate).

In this article, we propose a thermally responsive shape-memory polymer (SMP) consisting of poly(ethylene carbonate) and non-deteriorated lignin nanoparticles. This SMP was obtained readily by thermal kneading and melt molding without requiring any chemical reaction. The shape-recovering properties of the SMP can be tuned by changing the feed ratio of the components. The estimation of viscoelastic, thermal and mechanical properties of the SMP reveals that the stepwise structural transitions in the SMP rendered a dynamic shape-recovering behavior.

Plant-Based Antioxidant Nanoparticles without Biological Toxicity.

Here, we present a function to derive non-deteriorated nanoparticulated lignin as an antioxidant without biological toxicity that is supplied through the simultaneous enzymatic saccharification and comminution of plants. The lignin exhibits an oxygen radical absorption capacity, even in its macromolecular nature. The non-deteriorated lignin nanoparticles never inhibit the biological activity of living things, despite their antioxidant nature. The oxygen radical absorption capacity of lignin is dependent on its botanical origin and monomeric structure. A stable organic radical in lignin is responsible for the antioxidant nature of non-deteriorated lignin. The organic radical of non-deteriorated lignin, which yields a distinct signal on electron spin resonance spectra, serves as a spin trap reagent that detects the emergence of short lifespan radicals as the change of radical concentration of the lignin. The presented discovery of non-deteriorated lignin will induce not only the industrial utilization of plant biomass polymers in pharmaceuticals and reagents, but also advance our scientific understanding of the antioxidant function of native lignin.

Utilization of Lignocellulosic Biomass via Novel Sustainable Process.

In this review, we show novel methods for utilizing lignocellulosic biomass, polysaccharides, and lignin. Firstly, the simultaneous enzymatic saccharification and comminution (SESC) of plant materials is described as an extraction method for lignocellulosic biomass that does not require toxic reagents or organic solvents. Secondly, we demonstrate the material utilization of non-deteriorated lignocellulosic biomass extracted by SESC, such as for sugar and ethanol synthesis, and as a heatproof filler. Finally, we exhibit the use of a functional monomer (e.g., in disinfection chemicals, cesium chelation, and building blocks for polymers), 2-pyrone-4,6-dicarboxylic acid, derived from lignin via metabolic degradation.

Application of microalgae hydrolysate as a fermentation medium for microbial production of 2-pyrone 4,6-dicarboxylic acid.

Actual biomass of microalgae was tested as a fermentation substrate for microbial production of 2-pyrone 4,6-dicarboxylic acid (PDC). Acid-hydrolyzed green microalgae Chlorella emersonii (algae hydrolysate) was diluted to adjust the glucose concentration to 2 g/L and supplemented with the nutrients of Luria-Bertani (LB) medium (tryptone 10 g/L and yeast extract 5 g/L). When the algae hydrolysate was used as a fermentation source for recombinant Escherichia coli producing PDC, 0.43 g/L PDC was produced with a yield of 20.1% (mol PDC/mol glucose), whereas 0.19 g/L PDC was produced with a yield of 8.6% when LB medium supplemented with glucose was used. To evaluate the potential of algae hydrolysate alone as a fermentation medium for E. coli growth and PDC production, the nutrients of LB medium were reduced from the algae hydrolysate medium. Interestingly, 0.17 g/L PDC was produced even without additional nutrient, which was comparable to the case using pure glucose medium with nutrients of LB medium. When using a high concentration of hydrolysate without additional nutrients, 1.22 g/L PDC was produced after a 24-h cultivation with the yield of 16.1%. Overall, C. emersonii has high potential as cost-effective fermentation substrate for the microbial production of PDC.

Chiral-Linkage-Induced Hierarchical Ordering of Colloidal Achiral Nanotubes in their Thixotropic Gel.

Macroscopic continuous hierarchical ordering of achiral nanotube "imogolite" was achieved by thixotropic gelation of imogolite with chiral hydroxy acid and their flow-orienting/subsequent standing for uniaxial alignments of imogolite. The chirality change of the hydroxy acids resulted in an inversion of the helical ordering. The study presented here first exhibits the millimeter-scale supramolecular chirality induced by angstrom-scale molecular handedness in the architecture of nanotubes.

Helical alignment inversion of microtubules in accordance with a structural change in their lattice.

Giant helical (oriented chiral nematic) alignments of microtubules of nanometer to centimeter lengths are known to form over a temperature gradient during anisotropic spiral propagation via tubulin dimer addition in a capillary cell. Such helical alignments may be modified by the addition of either paclitaxel or dimethyl sulfoxide, which induces a lattice (helical) structural change in the microtubule itself. In this study, we found that the lattice structural change of microtubules brings about inversion of microtubule alignments in the helical ordering. Based on microscopy and scattering data, a mechanism for the helical ordering of microtubules is discussed in relation to their lattice (helical) structure.

Preparation of a sulfo-group-containing rod-like polysilsesquioxane with a hexagonally stacked structure and its proton conductivity.

A sulfo-group-containing rod-like polysilsesquioxane with a hexagonally stacked structure (PSQ-SO3H) was successfully prepared by oxidation and hydrolytic polycondensation of 3-mercaptopropyltrimethoxysilane (MPTMS) in a mixed aqueous solution of NaOH and H2O2. The X-ray diffraction pattern of the PSQ-SO3H film exhibited three diffraction peaks with a d-value ratio of 1:1/√3:1/2, indicating the formation of a hexagonally stacked structure. In addition, the transmission electron microscopy image of PSQ-SO3H exhibited a striped pattern, indicating that the rod-like PSQs were stacked in a parallel fashion. The presence of ionic side-chains composed of the sulfonate anions and sodium cations during the hydrolytic polycondensation of MPTMS was found to be essential for the formation of this regularly structured PSQ. Finally, the proton conductivity of the PSQ-SO3H film, determined by using complex impedance spectroscopy, was relatively high (>10(-2) S cm(-1)) at 80 °C and 30-90 % relative humidity.

Direct evidence for structural transition promoting shear thinning in cylindrical colloid assemblies.

In this paper, we describe stimuli-responsive hydrogels prepared from a rigid rod-like polyelectrolyte 'imogolite' and a dicarboxylic acid. The hydrogel exhibited thixotropy in response to mechanical shock within the order of seconds or sub-seconds. Here, using the latest structural/rheological characterisation techniques, the relationship between the structural transition processes and the shear thinning was estimated. The evidence obtained by the experiments revealed for the first time the direct relationship between the microscopic structural change and the macroscopic thixotropic behavior that have been extensively discussed. The thixotropic hydrogel has the hierarchical architecture in the combination of imogolite and dicarboxylic acid, i.e., sheathed nanotubes/hydroclusters of cross-bridged nanotubes/frameworks. The formation and disintegration of the network structure upon resting and agitating, respectively, were the origin of gel/sol transition (thixotropy), although the hydroclusters of cross-bridged nanotubes were maintained throughout the transition.

Thermoresponsive synthetic polymer-microtubule hybrids.

Thermoresponsive hybrids consisting of synthetic polymers and microtubules (MTs), i.e., assemblies of tubulins, were prepared by bonding MTs covalently to a few reactive units in a macromolecular strand. The hybrids exhibited the gel/sol transition because of the "assembling of tubulins to MTs/disintegrating of MTs to tubulins" by the temperature change between 37 and 4 °C, respectively. The viscoelastic behaviors of the hybrid gels depended upon the quantity of polymer feed and the amount of resulting covalent bonds between the polymers and tubulin units. Furthermore, in a confined space of a thin and long rectangular cell with the temperature gradient from 4 °C (cold terminal) to 37 °C (warm terminal), the sol state hybrid turned to the gel state that propagated from the warm terminal toward the cold terminal to form uniaxially oriented MT arrays. Upon changing the temperature of the whole system between 37 and 4 °C, the uniaxial arrays appeared/disappeared reversibly.

Structural and mechanical properties of Laponite-PEG hybrid films.

Inorganic/organic hybrids were obtained by the sol-gel type organic modification reaction of Laponite sidewalls with poly(ethylene glycol) (PEG) bearing alkoxysiloxy terminal functionality. By casting an aqueous dispersion of the hybrid, the flexible and transparent hybrid films were obtained. Regardless of the inorganic/organic component ratio, the hybrid film had the ordered structure of Laponite in-plane flat arrays. The mechanical strength of hybrid films was drastically improved by the presence of cross-linking among alkoxysilyl functionalities of PEG terminals and the absence of PEG crystallines. Hybrid films, especially those that consisted of PEG with short chain, showed good mechanical properties that originate from quasi-homogeneous dispersion of components due to anchoring of PEG terminal to Laponite sidewall and interaction of PEG to Laponite surface.

Controlled clockwise-counterclockwise motion of the ring-shaped microtubules assembly.

The microtubule (MT)-kinesin system has been proposed as the building block of biomolecular motor based artificial biomachines. Considerable efforts have been devoted to integrate this system that produced a variety of ordered structures including the ring-shaped MT assembly which is being considered as a promising candidate for the further development of the biomachines. However, lack of proper knowledge that might help tune the direction of motion of ring-shaped microtubule assembly from counterclockwise to clockwise direction, and vice versa, significantly restricted their potential applications. We report our success in controlling the direction of rotational motion of ring-shaped MT assembly by altering the preparation conditions of microtubules. The change in the direction of rotation of MT rings could be interpreted in terms of the accompanied structural rearrangement of the MT lattice. For achieving handedness-regulated efficient biomachines having tunable asymmetric property, our study will be significantly directive.