Surface Functionalization of Bamboo via Photo-Grafting Tannic Acid for Enhanced Silver Ion Loading Properties.

Photo-grafting is a gentle, simple, and precise approach to incorporating specific functional molecules for the surface functionalization of substrates. In this work, ultraviolet (UV)-induced tannic acid (TA) grafting onto the surface of bamboo was proposed as a viable strategy for functionalizing bamboo. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) clearly indicated that TA was successfully introduced to the bamboo's surface. The optimal conditions for the grafting reaction were determined to be 15 mM Methyl-2-benzoylbenzoate (BB), 30 mM TA, 20 min, and a pH = 8. Under these conditions, the amount of TA grafted onto the bamboo's surface was measured to be 19.98 µg/cm2. Results from Inductively Coupled Plasma (ICP) and Energy Dispersive Spectrometer (EDS) analyses showed that the silver ion loading capacity of tannic acid-grafted bamboo was significantly improved compared to that of raw bamboo and tannic acid-impregnated bamboo. Furthermore, the presence of TA grafted on the bamboo's surface exhibited a positive correlation with the loading of silver ions, indicating that grafted TA plays an important role in the surface functionalization of bamboo. We believe that photo-grafted TA may help generate multifunctional bamboo with diverse properties.

Unraveling the Lignin Structural Variation in Different Bamboo Species.

The structure of cellulolytic enzyme lignin (CEL) prepared from three bamboo species (Neosinocalamus affinis, Bambusa lapidea, and Dendrocalamus brandisii) has been characterized by different analytical methods. The chemical composition analysis revealed a higher lignin content, up to 32.6% of B. lapidea as compared to that of N. affinis (20.7%) and D. brandisii (23.8%). The results indicated that bamboo lignin was a p-hydroxyphenyl-guaiacyl-syringyl (H-G-S) lignin associated with p-coumarates and ferulates. Advanced NMR analyses displayed that the isolated CELs were extensively acylated at the γ-carbon of the lignin side chain (with either acetate and/or p-coumarate groups). Moreover, a predominance of S over G lignin moieties was found in CELs of N. affinis and B. lapidea, with the lowest S/G ratio observed in D. brandisii lignin. Catalytic hydrogenolysis of lignin demonstrated that 4-propyl-substituted syringol/guaiacol and propanol guaiacol/syringol derived from ß-O-4' moieties, and methyl coumarate/ferulate derived from hydroxycinnamic units were identified as the six major monomeric products. We anticipate that the insights of this work could shed light on the sufficient understanding of lignin, which could open a new avenue to facilitate the efficient utilization of bamboo.

Preparation of High-Toughness Lignin Phenolic Resin Biomaterials Based via Polybutylene Succinate Molecular Intercalation.

Lignin has many potential applications and is a biopolymer with a three-dimensional network structure. It is composed of three phenylpropane units, p-hydroxyphenyl, guaiacyl, and syringyl, connected by ether bonds and carbon-carbon bonds, and it contains a large number of phenol or aldehyde structural units, resulting in complex lignin structures. This limits the application of lignin. To expand the application range of lignin, we prepared lignin thermoplastic phenolic resins (LPRs) by using lignin instead of phenol; these LPRs had molecular weights of up to 1917 g/mol, a molecular weight distribution of 1.451, and an O/P value of up to 2.73. Due to the complex structure of the lignin, the synthetic lignin thermoplastic phenolic resins were not very tough, which greatly affected the performance of the material. If the lignin phenolic resins were toughened, their application range would be substantially expanded. Polybutylene succinate (PBS) has excellent processability and excellent mechanical properties. The toughening effects of different PBS contents in the LPRs were investigated. PBS was found to be compatible with the LPRs, and the flexible chain segments of the small PBS molecules were embedded in the molecular chain segments of the LPRs, thus reducing the crystallinities of the LPRs. The good compatibility between the two materials promoted hydrogen bond formation between the PBS and LPRs. Rheological data showed good interfacial bonding between the materials, and the modulus of the high-melting PBS made the LPRs more damage resistant. When PBS was added at 30%, the tensile strength of the LPRs was increased by 2.8 times to 1.65 MPa, and the elongation at break increased by 31 times to 93%. This work demonstrates the potential of lignin thermoplastic phenolic resins for industrial applications and provides novel concepts for toughening biobased aromatic resins with PBS.

Effects of cold storage and 1-methylcyclopropene treatments on ripening and cell wall degrading in rabbiteye blueberry (Vaccinium ashei) fruit.

The effect of postharvest 1-methylcyclopropene and/or cold storage application on texture quality parameters during storage was determined. The changes in fruit quality (including weight loss, firmness, total soluble solids content, and ethylene production), cell wall material (including water-soluble fraction, ethylenediaminetetraacetic acid-soluble fraction, Na2CO3-soluble fraction, 4% KOH-soluble fraction, and 14% KOH-soluble fraction), and cell wall hydrolase activities (including polygalacturonase, endo-1,4-beta-D-glucanase, pectinesterase, alpha-L-arabinofuranosidase, and beta-galactosidase) were periodically measured up to 25 days after postharvest treatments. The application of cold storage reduced weight loss, ethylene production, and delayed ripening of blueberry fruit. The inhibition of senescence was associated with suppressed increase in cell wall hydrolase activities and retarded solubilization of pectins and hemicelluloses. Furthermore, no obvious differences in firmness, weight loss, ethylene production, and cell wall hydrolase activities between fruits with or without 1-methylcyclopropene application were observed, while significant lower levels of the detected parameters were found in cold storage fruit compared with fruit stored in room temperature. Thus, cold storage can be viewed as an effective means to extend the shelf life of blueberry fruit.

Synthesis, characterization and antifungal properties of dehydroabietic acid modified chitosan.

The bioactivities of pristine chitosan are considerable weak compared with the commercial chemicals, which has restricted its broad application prospects in food packaging and preservation. In order to obtain a safe, biologically derived fruits preservative with excellent antifungal properties, dehydroabietic acid (DHA) was used to modify chitosan (CS). The structural characterization of modified chitosans were identified by FTIR and 1H NMR spectra. The XRD pattern showed the modified chitosan changed the crystal structure due to the modification of the amino and/or hydroxyl groups on the chitosan. Their antifungal activities against Penicillium digitutim and Penicillium italicum were investigated in vitro using the radial growth assay and the minimal inhibitory concentration assay. The study also examined the differences in antifungal effect among three modified chitosans. The results showed that DHA only conjugated thehydroxyl group at C-6, bearing free amino group at C-2, exhibited the strongest antifungal effect, with a minimum inhibitory concentration (MIC) of 200 µg/mL. In addition, a comparison of the antifungal activity of the modified compounds with different concentrations of Imazalil demonstrated that the modified biologic antifungal agent was as effective as Imazalil. CSDA can achieve 100 % inhibition of P. digitutim at concentrations >100 µg/mL and remain unchanged for a long time. Because CSDA can enhance the shelf life of longans, DHA-CS, chitosan derivatives, have tremendous promise for use in fruits preservation.

Synthesis, characterization and antifungal properties of maleopimaric anhydride modified chitosan.

Fruit spoilage can cause huge economic losses, in which fungal infection is one of the main influencing factors, how to effectively control mould and spoilage of fruits and prolong their shelf-life has become a primary issue in the development of fruit and vegetable industry. In this study, rosin derivative maleopimaric anhydride (MPA) was combined with biodegradable and antifungal chitosan (CS) to enhance its antifungal and preservative properties. The modified compounds were characterized by FTIR, 1H NMR spectra and XRD, and the in vitro antifungal properties of the modified compounds were evaluated by the radial growth assay and the minimal inhibitory concentration assay. The preservation effect on small mandarin oranges and longan was studied. The analysis revealed that the modification product (CSMA) of MPA access to C6-OH of CS had a better antifungal effect. In addition, CSMA was more environmentally friendly and healthier than the commercially available chemical preservative (Imazalil), and had the same antifungal preservative effect in preserving small mandarin orange, and was able to extend the shelf life to >24 d. In the preservation of longan, CSMA was more effective against tissue water loss and was able to maintain the moisture in the longan pulp and extend the shelf life. Therefore, CSMA has good application potentials in longan keeping-fresh.

Sulfomethylation reactivity enhanced the Fenton oxidation pretreatment of bamboo residues for enzymatic digestibility and ethanol production.

Bamboo is considered a renewable energy bioresource for solving the energy crisis and climate change. Dendrocalamus branddisii (DB) was first subjected to sulfomethylation reaction at 95°C for 3 h, followed by Fenton oxidation pretreatment at 22°C for 24 h. The synergistic effect of combined pretreatment dramatically improved enzymatic digestibility efficiency, with maximum yield of glucose and ethanol content of 71.11% and 16.47 g/L, respectively, increased by 4.7 and 6.11 time comparing with the single Fenton oxidation pretreatment. It was found that the hydrophobicity of substrate, content of surface lignin, degree of polymerization, and specific surface area have significant effects on the increase of enzymatic saccharification efficiency. It also revealed that sulfomethylation pre-extraction can improve the hydrophilicity of lignin, leading to the lignin dissolution, which was beneficial for subsequent Fenton pretreatment of bamboo biomass. This work provides some reference for Fenton oxidation pretreatment of bamboo biomass, which can not only promote the utilization of bamboo in southwest China, but also enhances the Fenton reaction in the bamboo biorefinery.

Slow-release antimicrobial preservation composite coating based on bamboo-derived xylan-A new way to preserve blueberry freshness.

In recent years, the biocompatibility and environmental friendliness of xylan-based materials have demonstrated great potential in the field of food packaging and coatings. In this study, the cationized xylan based composite coating (CXC) was developed using a hybrid system of cationic-modified bamboo xylan (CMX) and sodium alginate (SA) combined with thyme oil microcapsules (TM). The optimized CXC-B was composed of 1.27 % TM, 2.42 % CMX (CMX: SA = 3:2), and 96.31 % distilled water. When applied to the surface of a blueberry, the CXC-B treatment extended the ambient storage time of the fruit to 10 days while substantially reducing its morbidity (P < 0.05) and protecting its texture, flavor, and nutritional integrity. The resulting composite coating provides a promising solution to the problem of blueberry perishability during ambient storage.

Interfacial modulation of Ti3C2Tx MXene using functionalized cellulose nanofibrils for enhanced electrochemical actuation.

Electrochemical actuators (ECAs) with low voltage actuation and large deformation ranges generally require electrode materials with high ion kinetic energy transport, high charge storage, and excellent electrochemical-mechanical properties. However, the fabrication of such actuators remains a major challenge. In the present work, hybrid electroactive films were fabricated by self-assembling one-dimensional functionalized cellulose nanofibrils (CNFs) with two-dimensional MXene (Ti3C2Tx). The obtained ECA actuators fabricated by carboxymethylated cellulose nanofibrils (consisting of -CH2COO-surface groups) with Ti3C2Tx integrate excellent curvature (0.1041 mm-1), mechanical strength (21.68 MPa), a bending strain of 0.50 %, and a good actuation displacement of 9.3 mm at a low voltage range of -0.6 to 0.3 V. This may be attributed to the enlarged layer spacing (15.34 Å), which makes the embedding and transport of H+ easier, and excellent adaptivity of mechanical properties achieved by molecular-scaled strong hydrogen bonding, leading to better actuation performance. This study provides a potential research direction for the preparation of ECAs with large actuation deformation.

Phyllostachys nigra (Lodd. ex Lindl.) derived polysaccharide with enhanced glycolipid metabolism regulation and mice gut microbiome.

This study focuses on the characterization and regulation of glycolipid metabolism of polysaccharides derived from biomass of Phyllostachys nigra (Lodd. ex Lindl.) root (PNr). The extracts from dilute hydrochloric acid, hot water, and 2 % sodium hydroxide solution were characterized through molecular weight, gel permeation chromatography, monosaccharides, Fourier transform infrared, and nuclear magnetic resonance spectroscopy analyses. Polysaccharide from alkali extraction and molecular sieve purification (named as: PNS2A) exhibited optimal inhibitory of 3T3-L1 cellular differentiation and lowered insulin resistance. The PNS2A is made of a hemicellulose-like main chain of →4)-ß-D-Xylp-(1→ that was connected by branches of 4-O-Me-α-GlcAp-(1→, T-α-D-Galp-(1→, T-α-L-Araf-(1→, →2)-α-L-Araf-(1→, as well as ß-D-Glcp-(1→4-ß-D-Glcp-(1→ fragments. Oral delivery of PNS2A in diabetes mice brought down blood glucose and cholesterol levels and regulated glucose and lipid metabolism. PNS2A alleviated diabetes symptoms and body weight and protected liver and kidney function in model animals by altering the gut microbiome. Polysaccharides can be a new approach to develop bamboo resources.

Modified acid polysaccharide derived from Salvia przewalskii with excellent wound healing and enhanced bioactivity.

Acid polysaccharide was extracted from Salvia przewalskii root powders (PSP), purified by diethylaminoethyl cellulose column (DEAE-52) and molecular sieve (PSP2). PSPm1 was obtained by modifying PSP2 with nitrite and phosphoric acid. The chemical structure of PSP2 and PSPm1 exhibited notable distinctions, primarily due to the absence of arabinose and promotion of glucuronic acid (GlcA). The structure of PSPm1 was deduced through the utilization of 1H, 13C, and 2-D NMR. The main chain was linked by α-D-Galp(1 â†’ 3)-α-Glcp-(1 â†’ fragments and →6)-ß-D-Galp fragments, with the presence of →4)-α-D-GlcpA-(1 â†’ 6)-ß-D-Galp-(1 â†’ ï¼Œ â†’ 4)-α-D-GalAp-(1 â†’ 2,4)-α-D-Rhap-(1 â†’ fragments and →6)-α-Glcp-(1 â†’ 2,4)-ß-D-Manp-(1 â†’ fragments. PSPm1 exhibited different immunoregulatory bioactivity in vitro, including haemostatic effects indicated by activated clotting time of 55.5 % reduction by the activated clotting time (ACT) test and wound healing function in vivo. PSPm1 also displayed better anti-tumor biological effects than unmodified. The structure-activity dissimilarity between PSP2 and PSPm1 primarily stems from variations in molecular weight (Mw), monosaccharide composition, and branching patterns. The modification of polysaccharides from the extract residues of Chinese medicinal materials may be a new form of drug supplements.

Structural variation of bamboo lignin before and after ethanol organosolv pretreatment.

In order to make better use of lignocellulosic biomass for the production of renewable fuels and chemicals, it is necessary to disrupt its recalcitrant structure through pretreatment. Specifically, organosolv pretreatment is a feasible method. The main advantage of this method compared to other lignocellulosic pretreatment technologies is the extraction of high-quality lignin for the production of value-added products. In this study, bamboo was treated in a batch reactor with 70% ethanol at 180 °C for 2 h. Lignin fractions were isolated from the hydrolysate by centrifugation and then precipitated as ethanol organosolv lignin. Two types of milled wood lignins (MWLs) were isolated from the raw bamboo and the organosolv pretreated residue separately. After the pretreatment, a decrease of lignin (preferentially guaiacyl unit), hemicelluloses and less ordered cellulose was detected in the bamboo material. It was confirmed that the bamboo MWL is of HGS type (p-hydroxyphenyl (H), vanillin (G), syringaldehyde (S)) associated with a considerable amount of p-coumarate and ferulic esters of lignin. The ethanol organosolv treatment was shown to remove significant amounts of lignin and hemicelluloses without strongly affecting lignin primary structure and its lignin functional groups.

Spectroscopy and visible-light driven photocatalytic properties of a microcrystalline Cu-complex derived from a novel Gabapentin Schiff base.

A novel Gabapentin derivative Schiff base Gasa was synthesized by condensing Gabapentin with salicylaldehyde, which was further coordinated with Cu2+ in methanol to give a microcrystalline Cu(II) complex Cu(Gasa)2. The synthesized Gasa and Cu(Gasa)2 were further characterized by single-crystal X-ray diffraction, scanning electron microscopy (SEM), as well as the FT-IR, Raman, electronic and fluorescence spectra. Cu(Gasa)2 exhibited excellent visible-light driven photocatalytic activities in removal of Congo red (CR) and Methylene blue (MB) dyes from aqueous solution in the presence of H2O2 as oxidant. It was revealed that ∙OH radicals played the most important role in the photodegradation processes of organic dyes, and the photodegradation of CR and MB fitted well with the pseudo-first-order kinetic model. In addition, solid state luminescent properties of Gasa and Cu(Gasa)2 were also studied in detail.

Mechanistic investigation of cellulose regulating the morphology and photocatalytic activity of Al-doped ZnO.

The morphology of metal oxide is a crucial factor for improving of catalysis properties. As a renewable and environmentally friendly biomass material, cellulose has been widely used to induce the morphology of semiconductors. The contributions of cellulose hydroxyl groups and spatial hindrance in tailoring Al doped ZnO (AZO) morphologies were investigated. The morphology of AZO could be gradually induced from flake-like to flower-like with the increase of cellulose hydroxyl content per unit volume. At the same time, the changes in spatial hindrance had no apparent effect on the morphology of AZO. So the cellulose hydroxyl groups that act to induce the in situ growth of AZO nanoparticles on cellulose substrates. The results further confirmed the strong interaction between cellulose hydroxyl groups and Zn2+. In addition, the photocatalytic activities of Al-doped ZnO/cellulose nanocomposites (AZOC) with different morphologies were evaluated by the degradation of bisphenol A (BPA). The high hydroxyl contents of cellulose substrates contributed to the growth of flower-like AZO with high light utilization and photocatalytic activity. This work proposed cleaner strategies to modify semiconductor morphologies for photocatalysis by regulating the content of cellulose hydroxyl contents.

Effects of salicylic acid-grafted bamboo hemicellulose on gray mold control in blueberry fruit: The phenylpropanoid pathway and peel microbial community composition.

Bamboo hemicellulose (HC) is a natural plant polysaccharide with good biocompatibility and biodegradability. But its poor antibacterial activity limits its application in fruits preservation. In this study, based on the good inducer of salicylic acid (SA) for plant diseases resistance, a novel antibacterial coating material was synthesized by grafting SA onto HC. The study aimed to investigate the synergistic effect of HC-g-SA on antibacterial ability, induces diseases resistance and microbial community composition of postharvest fruit. The graft copolymer treatment significantly reduced the incidence of gray mold caused by Botrytis cinerea in blueberries during storage (P < 0.05), and significantly stimulated the activity of key enzymes, including phenylalanine ammonia-lyase, chalcone isomerase, laccase, and polyphenol oxidase, leading to an increase in fungicidal compounds such as flavonoids, lignin, and total phenolics produced by the phenylpropanoid pathway in blueberries (P < 0.05). Moreover, the HC-g-SA coating altered bacterial and fungal community composition such that the abundance of postharvest fruit-peel pathogens was significantly reduced. After 8 days storage, the blueberry fruits treated by HC-g-SA had a weight loss rate of 12.42 ± 0.85 %. Therefore, the HC-g-SA graft copolymer had a positive impact on the control of gray mold in blueberry fruit during postharvest storage.

An innovative and efficient hydrogen peroxide-citric acid pretreatment of bamboo residues to enhance enzymatic hydrolysis and ethanol production.

Organic peracids has attracted widespread attention from researchers in biomass pretreatment. As a weak acid with high production, low price and toxicity, citric acid (CA) was mixed with hydrogen peroxide at the room temperature to generate peroxy-citric acid with strong oxidative functions. An innovative and efficient pretreatment method using peroxy-citric acid (HPCA) was proposed to enhance enzymatic hydrolysis and bioethanol production of bamboo residues. After D. giganteus (DG) was pretreated with HPCA at 80 °C for 3 h, lignin of 95.36% and xylan of 55.41% was effectively removed, and the enzymatic saccharification yield of HPCA-treated DG enhanced by about 8-9 times compared with CA pretreated DG. The ethanol recovery of 17.18 g/L was achieved. This work provided a reference for mild biomass pretreatment, which will promote the large-scale application of organic peracids system in biorefinery processes.

Chitosan-tannin adhesive: Fully biomass, synthesis-free and high performance for bamboo-based composite bonding.

Inspired by phenol-amine chemistry of mussels, a synthesis-free and fully biomass adhesive composed of chitosan and tannin (CST) was successfully developed by a facile method. The performance of CST adhesive for bonding bamboo, wood and bamboo-wood substrates were tested. When 160 °C hot-press temperature was used, dry lap shear strength above 5.00 MPa was obtained. The CST adhesive has remarkable water resistance and low cure temperature as high wet shear strength of 2.37 MPa for plybamboo specimens was achieved after 3 h boiling in water even though low hot-press temperature of 100 °C was applied. Further, high strength of 1.78 MPa remained after 72 h boiling. With higher hot-press temperatures used, wet shear strength above 3.60 MPa was achieved. The adhesion performance for wood substrate was also superior to other phenol-amine adhesives reported in literatures. The bamboo-wood composites assembled with CST adhesive show excellent mechanical performance, specifically modulus of rupture (MOR) of 100-133 MPa and modulus of elasticity (MOE) of 10-13 GPa were achieved with different hot-press temperatures used. Given the advantages including outstanding water resistance, facile preparation, fully biomass, and low cure temperature, CST adhesive exhibited great potential to be an ideal alternative to formaldehyde-based resin for wood and bamboo bonding.

Sequential extraction, structural characterization, and antioxidant activity of polysaccharides from Dendrocalamus brandisii bamboo shoot shell.

Polysaccharides including water-soluble fraction (W), 1,2-Cyclohexanediaminetetraacetic acid (CDTA)-soluble fraction (CA), sodium carbonate (Na2CO3)-soluble fraction (SC), 1 M potassium hydroxide (KOH)-soluble fractions (PH1), and 4 M KOH-soluble fraction (PH4) were successively extracted from Dendrocalamus brandisii bamboo shoot shells using water, CDTA, Na2CO3, and KOH solution. The analytical methods were employed to initially identify the structural characteristics of the five polysaccharide fractions, and their antioxidant capacities in vitro were determined. According to the data, the average molecular weight of the five polysaccharide fractions was between 4 816 and 993 935 Da. In all four types (CA, SC, PH1, and PH4), xylose was the most abundant monosaccharide, especially in PH1 and PH4. Both PH1 and PH4 were found to contain 1,4-ß-d-Xylp as their main chain, as determined by nuclear magnetic resonance (NMR) spectroscopy. Additional research into CA and SC's antioxidant potential is required since they both showed potent in vitro antioxidant activities.

Bamboo fiber strengthened poly(lactic acid) composites with enhanced interfacial compatibility through a multi-layered coating of synergistic treatment strategy.

In this study, a mild and eco-friendly synergistic treatment strategy was investigated to improve the interfacial compatibility of bamboo fibers with poly(lactic acid). The characterization results in terms of the chemical structure, surface morphology, thermal properties, and water resistance properties demonstrated a homogeneous dispersion and excellent interfacial compatibility of the treated composites. The excellent interfacial compatibility is due to multi-layered coating of bamboo fibers using synergistic treatment involving dilute alkali pretreatment, polydopamine coating and silane coupling agent modification. The composites obtained using the proposed synergistic treatment strategy exhibited excellent mechanical properties. Optimal mechanical properties were observed for composites with synergistically treated bamboo fiber mass proportion of 20 %. The tensile strength, elongation at break and tensile modulus of the treated composites were increased by 63.06 %, 183.04 % and 259.04 %, respectively, compared to the untreated composites. This synergistic treatment strategy and the remarkable performance of the treated composites have a wide range of applicability in bio-composites (such as industrial packaging, automotive lightweight interiors, and consumer goods).

Alkaline deacetylation-aided hydrogen peroxide-acetic acid pretreatment of bamboo residue to improve enzymatic saccharification and bioethanol production.

Bamboo pretreatment with alkaline deacetylation-aided hydrogen peroxide-acetic acid (HPAC-NaOH) was investigated for producing high-value-added products. Comparing with HPAC pretreated D. sinicus, the post-treatment of alkaline deacetylation resulted in higher glucose yield of 91.3% and ethanol concentrations of 17.20 g/L, increased by about 20-27%. A strong negative correlation between the content of acetyl with cellulose accessibility and enzymatic hydrolysis yield was showed. The deacetylation of HPAC-DS contributed to the increase of cellulase adsorption capacities in substrates and the variations of hydrophilicity, cellulose crystallinity, and degree of polymerization, which can generate highly reactive cellulosic materials for enzymatic saccharification to produce bioethanol. The HPAC-NaOH pretreatment can provide a promising approach to improve the bioconversion of bamboo to biofuels, and has broad space for the biorefinery of bamboo in the south of China.