Fruits are prone to deterioration during transportation and preservation, while conventional packaging materials generally pose a persistent threat to the environment. In the present study, a ...multifunctional green composite film was developed using solution casting method through the interactions of hydrogen bonds among carboxymethyl hemicellulose, sorbitol, and gallic acid, which was subsequently employed as functional materials for fresh fruit preservation application. In particular, the influence of the degree of substitution (DS) of carboxymethyl hemicellulose on the properties of the composite films was investigated. The results indicated that as the DS increased, the carboxymethyl hemicellulose/sorbitol/gallic acid composite film demonstrated a notable improvement in transmittance, air barrier property, and antibacterial activity. Specifically, the composite film (DS = 0.59) showed a 42.54 % increase in transmittance and a 48.31 % decrease in air permeability compared to the composite film containing hemicellulose (control sample). Furthermore, the composite film (DS = 0.59) displayed a desired inhibition effect against Staphylococcus aureus. Based on the 9-day blueberry preservation test, the composite film (DS = 0.59) exhibited a weight loss rate of 15.36 %, whereas the blank group retained a value up to 20.34 %. In addition, the increased DS was found to lead to the decreased tensile strength but improved elongation at break. Overall, the carboxymethyl hemicellulose/sorbitol/gallic acid green composite films, derived from natural bio-materials and free of environmental concerns, could hold great promise as a novel packaging material for fresh fruit preservation.
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•Carboxymethyl hemicellulose/sorbitol/gallic acid green composite film was prepared.•Effect of modified carboxymethyl hemicellulose on film properties was investigated.•Increased DS led to improvement in barrier properties and antibacterial activity.•Green composite film demonstrated superior preservation efficacy for blueberry.
Lytic polysaccharide monooxygenase (LPMO)-catalyzed oxidative processes play a major role in natural biomass conversion. Despite their oxidative cleavage at the surface of polysaccharides, ...understanding of their mode of action, and the impact of structural patterns of the cellulose fiber on LPMO activity is still not fully understood. In this work, we investigated the action of two different LPMOs from Podospora anserina on celluloses showing different structural patterns. For this purpose, we prepared cellulose II and cellulose III allomorphs from cellulose I cotton linters, as well as amorphous cellulose. LPMO action was monitored in terms of surface morphology, molar mass changes and monosaccharide profile. Both PaLPMO9E and PaLPMO9H were active on the different cellulose allomorphs (I, II and III), and on amorphous cellulose (PASC) whereas they displayed a different behavior, with a higher molar mass decrease observed for cellulose I. Overall, the pretreatment with LPMO enzymes clearly increased the accessibility of all types of cellulose, which was quantified by the higher carboxylate content after carboxymethylation reaction on LPMO-pretreated celluloses. This work gives more insight into the action of LPMOs as a tool for deconstructing lignocellulosic biomass to obtain new bio-based building blocks.
•We studied two LPMOs from Podospora anserina: PaLPMO9E and PaLPMO9H.•LPMOs are active on cellulose allomorphs I, II, III and on amorphous cellulose.•PaLPMO9H seemed more active than PaLPMO9E, especially on cellulose I.•LPMO action increases the accessibility to chemicals.
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•Carboxymethyl polysaccharides are usually prepared using chloroacetic acid.•They are good adsorbents of heavy metal ions in aqueous solutions.•Beads, hydrogels, composite and ...cross-linking enhance their mechanical strength.
The removal of hazardous heavy metals from the environment is imperative in order to have quality of water. Robust and eco-friendly technologies are required for the treatment of domestic, agricultural and industrial effluents. The effective treatment of wastewaters can be done using chemically modified polysaccharides as adsorbents of these toxic heavy metals. A popular method used by researchers to chemically polysaccharide adsorbents is carboxymethylation. Carboxymethyl polysaccharides, generally, have higher adsorption capacities for heavy metals than their unmodified forms. This paper reviews the applications of carboxymethyl polysaccharides as adsorbents of heavy metals in wastewaters. The review places particular emphasis on the use of carboxymethylated cellulose, chitosan and starch for the adsorption of heavy metals in contaminated aqueous environments. The literature reviewed generally showed that these carboxymethyl polysaccharides are good adsorbents of heavy metals. Some modifications, however, are required to enhance the chemical and mechanical strength of these carboxymethyl polysaccharides.
Nanocelluloses have unique morphologies, characteristics, and surface nanostructures, and are prepared from abundant and renewable plant biomass resources. Therefore, expansion of the use of ...CO2‐accumulating nanocelluloses is expected to partly contribute to the establishment of a sustainable society and help overcome current global environmental issues. Nanocelluloses can be categorized into cellulose nanonetworks, cellulose nanofibrils, and cellulose nanocrystals, depending on their morphologies. All of these materials are first obtained as aqueous dispersions. In particular, cellulose nanofibrils have homogeneous ≈3 nm widths and average lengths of >500 nm, and significant amounts of charged groups are present on their surfaces. Such charged groups are formed by carboxymethylation, C6‐carboxylation, phosphorylation, phosphite esterification, xanthation, sulfate esterification, and C2/C3 dicarboxylation during the pretreatment of plant cellulose fibers before their conversion into cellulose nanofibrils via mechanical disintegration in water. These surface‐charged groups in nanocelluloses can be stoichiometrically counterion‐exchanged into diverse metal and alkylammonium ions, resulting in surface‐modified nanocelluloses with various new functions including hydrophobic, water‐resistant, catalytic, superdeodorant, and gas‐separation properties. However, many fundamental and application‐related issues facing nanocelluloses must first be overcome to enable their further expansion.
Nanocelluloses have unique morphologies, characteristics, and surface nanostructures, and are prepared from abundant and renewable plant biomass resources. Nanocelluloses can be categorized into cellulose nanonetworks, cellulose nanofibrils, and cellulose nanocrystals, depending on their morphologies. Cellulose nanofibrils have significant amounts of charged groups on their surfaces. These surface‐charged groups can be stoichiometrically counterion‐exchanged to diverse metal and alkylammonium ions.
•Bio-based matrix was employed as a simple colorimetric sensor for ammonia gas.•Bromocresol purple was immobilized into cross-linked carboxymethyl cellulose xerogel.•Vapochromic freeze-dried xerogel ...introduced an instant color signal.•Detection process functions on both qualitative and quantitative levels.
Microporous cellulose xerogel can be defined as low density biomaterial that can be employed for a variety of promising applications of different fields. The characteristics of xerogel are a consequence of their microstructure. An easy-to-use and reversible solid-state colorimetric sensor for ammonia gas was developed by embedding a bromocresol purple (BCP) pH-sensory chromophore into the environmental friendly carboxymethyl cellulose as bio-based polymer (CMC) matrix. The bromocresol purple was immobilized into cross-linked carboxymethyl cellulose (CMC-BCP) xerogel followed by freeze-drying to introduce a microporous network of regenerated cellulose host in which bromocresol purple chromophore was immobilized to function as a spectroscopic probe guest. Identification of ammonia gas occurred via proton shift from the hydroxyl group of the BCP dye to ammonia nitrogen. Both qualitative and quantitative activities were determined. The architectures of the prepared cellulose xerogel at different degree of substitutions (DS) was investigated using Fourier-transform infrared spectroscopy (FTIR) and scan electron microscopy (SEM), which displayed a high porosity and pores diameter in the range of 10–50 μm. The resultant CMC-BCP displayed high sensitivity for gaseous ammonia. Moreover, excellent reversibility and short detection time were also monitored. The vapochromic xerogel provided an instant color alteration signal from yellow to purple when exposed to ammonia gas or an ammonium hydroxide aqueous environment as monitored by the absorption maxima, color coordinates and color strength. The visual color change of CMC-BCP xerogel was observed to alter in the order from yellow, orange, red to purple in proportional with raising the ammonia concentration in an aqueous environment. Moreover, the CMC-BCP xerogel displayed rapid response time, concentration detection limit as low as 9.0 × 10−2 ppb for ammonia in aqueous media, and very good reversibility.
•Two acidic polysaccharides were extracted from C. cornucopioides (CCPss).•The purified CCPss (CCPs-1 and CCPs-2) were structurally characterized.•Carboxyl groups were added into polysaccharide ...chains by carboxymethylation.•Nonselective carboxymethylation (C-2, C-4, C-6) occurred in cmCCPss.•Carboxymethylation improved the solubility and antioxidant activity of CCPss.
Herein, we isolated and purified polysaccharides from Craterellus cornucopioides. Chemical composition analysis revealed that both polysaccharides (CCPs-1 amd CCPs-2) were composed of different molar ratios of rhamnose, fucose, arabinose, xylose, mannose, glucose, and galactose. The structure of polysaccharides was determined using FT-IR, periodate oxidation, smith degradation, methylation analysis, and NMR, which demonstrated that the two polysaccharides were primarily connected by mannose with (1→3)-linked. Notably, the configuration of the two polysaccharides exhibited random coil with pyranoid polysaccharide containing α or β glycosidic bond. Furthermore, to increase the antioxidant activity of polysaccharides (CCPs-1 amd CCPs-2), two carboxymethylated polysaccharides were obtained as cmCCPs-1 and cmCCPs-2 with the degree of substitution values of 0.34 and 0.52, respectively. Structural analysis elucidated that nonselective carboxymethylation occurred in cmCCPs-1 and cmCCPs-2, where C-2, C-4 or C-6 were partially substituted. Of note, cmCCPs-2 exhibited the most significant antioxidant activity.
Background: The evaluation of toxicity is of paramount importance in the screening of a new compound. Basella alba mucilage possesses a versatile excipient property that can be innovated with its ...chemical modification to get the functionalized mucilage. A few pharmacological activities of Basella alba mucilage have also been reported earlier, but its toxicity study in rats has yet to be discussed. Aim: The study aims to assess the in vivo toxicity of carboxymethylated Basella alba mucilage in Wistar albino rats for 28 days. Material and Methods: In the current investigation, Carboxymethylated Basella alba mucilage is taken, and its subchronic toxicity study is carried out in forty-eight healthy rats (twenty-four male rats and 24 female rats), divided into four groups containing six rats of each sex. All the biochemical and hematological parameters and histopathological investigation were estimated for all the animal groups. Result: The subchronic toxicity study reveals that the modified mucilage is safe for all doses (20mg/kg body weight, 40mg/kg body weight, 80 mg/kg body weight). The study showed no significant difference in the dose group's behavioral toxicity, nephrotoxicity, and hepatotoxicity compared to the control. All the hematological and biochemical parameters lay in the normal range. The histopathological examination of treatment groups showed no abnormality or lesion in the tissue samples of internal organs. Conclusion: The study confirms the safety of Carboxymethylated Basella alba mucilage for use in pharmaceutical formulations.
Among the multiple industrial applications of carboxymethyl cellulose (CMC), those related to food and beverages industries (e.g. as thickener, stabilizer, emulsifier, binding agent), involve one ...fourth of the global CMC consumption. In the last years, a number of abundant and underutilized vegetable cellulose sources have been assayed as raw material for CMC production, as alternatives to cotton linters or cellulose feedstocks obtained from bleached pulps derived from wood. Alternatively, cellulose of microbial origin appears as a very promising highly pure raw material for CMC production.
Together with molecular weight and substituents distribution, it is well established that the degree of substitution (DS) of CMC plays a key role in most food and beverages applications. In the current contribution, highly pure cellulose of bacterial origin was used to produce CMC with tailored DS in a two-stage process consisting of alkalinization with sodium hydroxide, followed by etherification with sodium monochloroacetate. Aiming to get insight into how the carboxymethylation extent conferred to BC can be easily tuned within the DS interval allowed for food uses (i.e. 0.2–1.5), the effects of NaOH concentration, molar NaOH/anhydroglucose unit ratio, molar etherifying reagent/anhydroglucose unit ratio, and etherification time, were systematically analyzed. By proper control of those variables, CMC samples with tailored DS within the 0.60–1.52 interval could be successfully obtained. Samples with varying DS were further characterized by means of FTIR, solid state 13C NMR, XRD and TGA. The suitability of using TGA data for estimating the carboxymethylation extent achieved is proposed.
Carboxymethylation of BC and reaction conditions used to tailor DS within the interval allowed for food uses. Display omitted
•Bacterial cellulose proved useful as raw material for producing CMC.•Reaction conditions could be conveniently manipulated to tune the DS of CMC.•Characterization confirmed carboxymethylation and evidenced reduced crystallinity.•TGA data proved useful for estimating the carboxymethyl content of CMC samples.
Synopsis
Crosslinking microwave-assisted carboxymethyl lignin adsorbent exhibited superior adsorption performance for Pb2+, which was attributed to high carboxyl group content.
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...•Carboxymethyl lignin had high carboxyl content of 3.61 mmol/g by microwave-assisted.•Crosslinking microwave-assisted carboxymethyl lignin (C-MCML) exhibited superior adsorption capacity of 302.3 mg/g for Pb2+.•C-MCML can be regenerated and maintained the high adsorption efficiency.
An efficient lignin adsorbent for Pb2+ in water was synthesized by crosslinking microwave-assisted carboxymethyl lignin (C-MCML) and the saturated adsorption capacity for Pb2+ was 302.3 mg/g. Microwave irradiation showed a greater assisted ability in the carboxymethylation than that of traditional heating, and the carboxyl content of microwave-assisted carboxymethyl lignin could be raised to 3.61 mmol/g. The adsorption behavior of C-MCML also was studied by varying different parameters like pH, initial concentration of metal ions and shaking time. The adsorption isotherm was fitted well by Langmuir model, and the fitting saturated adsorption capacity was 323.6 mg/g. Meanwhile, the results of FTIR and XPS shown that main Pb2+ adsorption mechanimis was ion exchange by carboxyl. The adsorption capacity of C-MCML was still maintained at 90% after recycled for 10 times.
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