Cellulose nanocrystals (CNCs) have been widely used as renewable materials and tough nano-composites due to its excellent properties. Currently, the preparation methods of CNCs require substantial ...energy and time consumption and the use of toxic chemicals. Herein, cotton and other biomass feedstocks were treated with deep eutectic solvents (DESs) and subsequent high-pressure homogenization (HPH), which was a simple preparation procedure for CNCs. The morphological, spectroscopic, and stability properties of the as-prepared rod-shaped CNCs were characterized using zeta potential, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, fourier transform infrared spectroscopy and thermogravimetric techniques. CNCs with a diameter range of 50–100 nm and a length range of 500–800 nm were successfully assembled. The resulting CNC suspension was stable even after one month of storage. The solvent could be recycled successfully and reused for at least three additional pretreatment cycles while maintaining its pretreatment capability. The use of a DES as both the catalyst and solvent introduces a green chemical process that does not produce any hazardous waste and is an economical process because of the high recyclability (> 85%). The molecular structure changes of cellulose after HPH and DES treatment were also discussed. This is the first report on the recycling and reuse of a DES after preparing CNCs.
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•Phycobiliproteins have high potential pharmaceutical and biological properties.•Classification, structure, and stability of phycobiliproteins from microalgae.•Mechanism governing phycobiliproteins ...biosynthesis in microalgae.•Effect of strains, bioreactor design, cultivation on phycobiliproteins production.•Biomass harvesting, and phycobiliproteins extraction, purification and character.
Microalgae are considered as a great potential for reliable and sustainable feedstock for the production of biofuels and biochemically active compounds such as phycobiliproteins. Phycobiliproteins are a group of colored proteins present commonly not only in cyanobacteria (blue–green algae) but also in red algae, cryptomonads, etc. They are extensively commercially used in foods, cosmetics, biotechnology, pharmacology and medicine. Phycobiliproteins have high potential pharmaceutical and biological properties but their application is confronted with two major obstacles: (i) the upstream and downstream processes still have some hindrances such as selection of suitable microalgae strains, bioreactor design, culture conditions, etc.; (ii) the purification of phycobiliproteins from microalgae is still low. Biosynthesis of higher purity phycobiliproteins from microalgae is a multiple concomitant steps for which the main criteria and factors were discussed in this paper. This review highlights an overview on the phycobiliproteins application fields such as pharmaceutical, medicine, biological and diagnostic reagents, etc., and meanwhile provides an insight for further research in development, production, and application of phycobiliproteins.
The flexible hydrogel sensors in the field of artificial intelligence have been widely concerned, which could be applied in medical monitoring, human motion detection, and intelligent robots. ...However, the integration of the synergistic properties of excellent mechanical properties, temperature sensitivity, adhesion ability and self-healing ability for preparation of hydrogel-type strain sensor is still a challenge. Moreover, how can we recover cumulated sensors without affecting the environment? Herein, a self-healing hydrogel was prepared based on deep eutectic solvent (DES) combined with polyvinyl alcohol (PVA), and cellulose nanocrystals (CNCs), which has the peotential application as wearable strain sensors. The DES network crosslinks PVA/CMC-Na/CNCs through ionic bonds, and the overall network is further linked through physical entanglement and hydrogen bonding interactions. Interestingly, the hydrogel could sensitively detect large or subtle movements (such as finger bending, wrist bending, knee bending, pulse and pronounce), indicating its potential applications in human–computer interaction and personal health monitoring.
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The scientific community has been seeking cost‐competitive and green solvents with good dissolving capacity for the valorization of lignocellulosic biomass. At this point, deep eutectic solvents ...(DESs) are currently emerging as a new class of promising solvents that are generally liquid eutectic mixtures formed by self‐association (or hydrogen‐bonding interaction) of two or three components. DESs are attractive solvents for the fractionation (or pretreatment) of lignocellulose and the valorization of lignin, owing to the high solubility of lignin in DESs. DESs are also employed as effective media for the modification of cellulose to afford functionalized cellulosic materials, such as cellulose nanocrystals. More interestingly, biomassderived carbohydrates, such as fructose, can be used as one of the constituents of DESs and then dehydrated to 5‐hydroxymethylfurfural in high yield. In this review, a comprehensive summary of recent contribution of DESs to the processing of lignocellulosic biomass and its derivatives is provided. Moreover, further discussion about the challenges of the application of DESs in biomass processing is presented.
Going green: Cost‐competitive and green solvents with good dissolving capacity for the valorization of lingocellulosic biomass are required. This review discusses deep eutectic solvents as green solvents for the valorization of lignocellulosic biomass, which is generally composed of widely available, renewable, and low toxicity/nontoxic compounds.
Recently, valorization of lignocellulosic biomass, the most abundantly available biomass raw material on the Earth, to biofuels and chemicals has attracted great attention worldwide for the purpose ...of reducing our overwhelming reliance on the non-renewable petroleum resources. γ-Valerolactone (GVL) has recently been hailed as a versatile building block which can be derived from renewable lignocellulosic biomass resource for energy, chemical and material sectors. In this review, focus was principally put on the applications of GVL as a renewable carbon source for green solvents and transportation fuels. In addition, advances in the GVL production through selective reduction of commercial or biomass-derived levulinic acid (LA) and its esters using various hydrogen sources, mainly including molecule H2, formic acid (FA) and alcohols, have been carefully summarized. Moreover, assessment of the relative merits of different hydrogen sources for the GVL production has also been performed.
Highlights
An all-wood hydrogel was synthesized via a simply Hofmeister effect without the use of any chemical cross-linking agent.
The all-wood hydrogel shows a high tensile strength of 36.5 MPa, a ...strain up to ~ 438%, and good conductivity, and can accurately distinguish diverse large or subtle human movements.
The all-wood hydrogel has good recyclable, biodegradable, and adjustable mechanical properties.
Wood-based hydrogel with a unique anisotropic structure is an attractive soft material, but the presence of rigid crystalline cellulose in natural wood makes the hydrogel less flexible. In this study, an all-wood hydrogel was constructed by cross-linking cellulose fibers, polyvinyl alcohol (PVA) chains, and lignin molecules through the Hofmeister effect. The all-wood hydrogel shows a high tensile strength of 36.5 MPa and a strain up to ~ 438% in the longitudinal direction, which is much higher than its tensile strength (~ 2.6 MPa) and strain (~ 198%) in the radial direction, respectively. The high mechanical strength of all-wood hydrogels is mainly attributed to the strong hydrogen bonding, physical entanglement, and van der Waals forces between lignin molecules, cellulose nanofibers, and PVA chains. Thanks to its excellent flexibility, good conductivity, and sensitivity, the all-wood hydrogel can accurately distinguish diverse macroscale or subtle human movements, including finger flexion, pulse, and swallowing behavior. In particular, when “An Qi” was called four times within 15 s, two variations of the pronunciation could be identified. With recyclable, biodegradable, and adjustable mechanical properties, the all-wood hydrogel is a multifunctional soft material with promising applications, such as human motion monitoring, tissue engineering, and robotics materials.
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•Over physically mixed CuO-Pd/C furfural hydrogenation was performed with formic acid.•CuO firstly dissolved into Cu2+ by formic acid, then Cu2+ was reduced by the Pd-H.•Pd promoted ...the furfural conversion and Cu improved the furfuryl alcohol selectivity.•Cu-Pd alloys functioned well in this reaction with 98.1% furfuryl alcohol yield.•In-situ prepared Cu-Pd/C exhibited an excellent recycle stability.
Catalytic transfer hydrogenation (CTH) of bio-derived furfural (FF) to furfuryl alcohol (FFA) was performed using the physically mixed CuO-Pd/C as catalyst and formic acid (FA) as hydrogen donor. The evolution investigation of Cu showed the precursor CuO firstly dissolved into Cu2+ by FA and then formed coordination polymer-copper(II), which uniformly dispersed in reaction solution of 1, 4-dioxane. Subsequently the Cu2+ was in-situ reduced and Cu-Pd alloys formed simultaneously. The in-situ prepared nano Cu-Pd/C catalyst exhibited the best performance with a complete FF conversion and FFA selectivity of 98.1%. Reaction conditions test suggested that the FFA selectivity was greatly dependent on the Cu content. The underlying mechanism revealed that the Pd in Cu-Pd alloys mainly promoted the FF conversion by enhancing hydrogen adsorption, while the nano Cu for increasing FFA selectivity; the Cu-Pd alloys functioned in synergistic way. Leaching and recycling tests demonstrated an excellent stability of the Cu-Pd/C catalyst.
In the search of alternative resources to make commodity chemicals and transportation fuels for a low carbon future, lignocellulosic biomass with over 180-billion-ton annual production rate has been ...identified as a promising feedstock. This review focuses on the state-of-the-art catalytic transformation of lignocellulosic biomass into value-added chemicals and fuels. Following a brief introduction on the structure, major resources and pretreatment methods of lignocellulosic biomass, the catalytic conversion of three main components, i.e., cellulose, hemicellulose and lignin, into various compounds are comprehensively discussed. Either in separate steps or in one-pot, cellulose and hemicellulose are hydrolyzed into sugars and upgraded into oxygen-containing chemicals such as 5-HMF, furfural, polyols, and organic acids, or even nitrogen-containing chemicals such as amino acids. On the other hand, lignin is first depolymerized into phenols, catechols, guaiacols, aldehydes and ketones, and then further transformed into hydrocarbon fuels, bioplastic precursors and bioactive compounds. The review then introduces the transformations of whole biomass via catalytic gasification, catalytic pyrolysis, as well as emerging strategies. Finally, opportunities, challenges and prospective of woody biomass valorization are highlighted.
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•Structure, resources and pretreatment of lignocellulosic biomass are introduced.•Over 800 references related to catalytic conversion of lignocellulosic biomass are discussed.•Opportunities, challenges and prospective of current approaches are discussed.
The catalytic transformation of bio‐derived compounds, specifically 5‐hydroxymethylfurfural (HMF), into value‐added chemicals may provide sustainable alternatives to crude oil and natural gas‐based ...products. HMF can be obtained from fructose and successfully converted to 2,5‐diformylfuran (DFF) by an environmentally friendly organic electrosynthesis performed in an ElectraSyn reactor, using cost‐effective and sustainable graphite (anode) and stainless‐steel (cathode) electrodes in an undivided cell, eliminating the need for conventional precious metal electrodes. In this work, the electrocatalysis of HMF is performed by using green solvents such as acetonitrile, γ‐valerolactone, as well as PolarClean, which is used in electrocatalysis for the first time. The reaction parameters and the synergistic effects of the TEMPO catalyst and 2,6‐lutidine base are explored both experimentally and through computation modeling. The molecular design and synthesis of a size‐enlarged C3‐symmetric tris‐TEMPO catalyst are also performed to facilitate a sustainable reaction work‐up through nanofiltration. The obtained performance is then compared with those obtained by heterogeneous TEMPO alternatives recovered by using an external magnetic field and microfiltration. Results show that this new method of electrocatalytic oxidation of HMF to DFF can be achieved with excellent selectivity, good yield, and excellent catalyst recovery.
Up the tempo: An efficient TEMPO‐based electrocatalytic transformation of biomass‐based C6‐platform chemical 5‐hydroxymethylfurfural (HMF) to 2,5‐diformylfuran (DFF) is reported. The molecular design and comparison of homogeneous (native, size‐enlarged) and solid‐supported (SiliaCAT, TurboBeads) TEMPOs is discussed for the oxidation in the ElectraSyn reactor with cost‐effective electrodes and green solvents. Computational modeling reveals the synergistic effect of the catalyst/base system and facilitated the catalyst design.
•Arthrospira platensis WH879 shows high potential as an C-phycocyanin producer.•The average irradiance affects C-PC content and cell growth rate in an opposite way.•Controlling a lower nitrogen level ...was more favorable for C-PC accumulation.•Fed-batch cultivation with medium feeding effectively enhanced the C-PC production.
The C-phycocyanin generated in blue-green algae Arthrospira platensis is gaining commercial interest due to its nutrition and healthcare value. In this study, the light intensity and initial biomass concentration were manipulated to improve cell growth and C-phycocyanin production of A.platensis in batch cultivation. The results show that low light intensity and high initial biomass concentration led to increased C-phycocyanin accumulation. The best C-phycocyanin productivity occurred when light intensity and initial biomass concentration were 300μmol/m2/s and 0.24g/L, respectively. The fed-batch cultivation proved to be an effective strategy to further enhance C-phycocyanin production of A.platensis. The results indicate that C-phycocyanin accumulation not only requires nitrogen-sufficient condition, but also needs other nutrients. The highest C-phycocyanin content (16.1%), production (1034mg/L) and productivity (94.8mg/L/d) were obtained when using fed-batch strategy with 5mM medium feeding.
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