Removal Of Pectin Research Articles

Controlling strategies of methanol generation in fermented fruit wine: Pathways, advances, and applications.

Methanol is widely existed in fermented fruit wines (FFWs), and the concentration is excessive at times due to inappropriate fermentation conditions. Methanol is neurotoxic, and its metabolites of formaldehyde and formic acid can cause organic lesions and central respiratory system disorders. FFWs with unspecified methanol limits are often produced with reference to grape wine standards (250/400mg/L). To clarify the causes of methanol production in FFWs and minimize the methanol content, this study summarizes the current process methods commonly applied for methanol reduction in FFWs and proposes novel potential controlling strategies from the perspective of raw materials (pectin, pectinase, and yeast), which are mainly the low esterification modification and removal of pectin, passivation of the pectinase activity, and the gene editing of yeast to target the secretion of pectinases and modulation of the glycine metabolic pathway. The modified raw materials combined with optimized fermentation processes will hopefully be able to improve the current situation of high methanol content in FFWs. Methanol detection technologies have been outlined and combined with machine learning that will potentially guide the production of low-methanol FFWs and the setting of methanol limits for specific FFW.

Insight into Low-Temperature One-Step Biopreparation and Natural Dyeing of Cotton as an Environmentally Benign Route

The goal of this study is to present an environmentally benign route for cotton fabric and investigate the effect of different pretreatments in natural dyeing. In this context, conventional alkaline scouring, conventional hydrogen peroxide bleaching, low-temperature one-step biopreparation processes, namely enzymatic scouring (alkaline pectinase and alkaline pectinase-neutral cellulase combination) at 55 °C and enzyme-bleaching agent (hydrogen peroxide/sodium percarbonate/sodium perborate)-activator agent (TAED) combinations at 65 °C were applied to 100% cotton knitted fabric. The use of agricultural waste and eco-friendly mordants was preferred in natural dyeing. For this purpose, pretreated fabrics were dyed with the outer green shell of almond fruit extracts and a low amount of 0.4 g/L metal mordants (alum and iron(II) sulfate) in accordance with the simultaneous mordanting method. The dyeing properties of bio- and conventionally prepared cotton fabrics were examined in terms of colorimetric data (K/S, CIELa*b*C*h°) and wash fastness compared with water absorbency, whiteness, weight loss, pectin removal, and type of mordant. Excellent wash fastness values were achieved regardless of the type of pretreatment. Low-temperature one-step biopreparation can be a good substitute for conventional scouring and bleaching processes. Since different results can be achieved, it is essential to determine and evaluate all bioprocess conditions depending on the end-use characteristics of the textile (e.g. whether it will be white or dyed/printed, its color and lightness/darkness) at the laboratory and industrial scale applications.

The sequential microbial breakdown of pectin is the principal incident during water retting of jute (Corchorus spp.) bast fibres

The extraction of bast fibres such as jute from plant stems involves the removal of pectin, hemicellulose, and other noncellulosic materials through a complex microbial community. A consortium of pectinolytic bacterial strains has been developed and commercialized to reduce the retting time and enhance fibre quality. However, there are currently no studies on jute that describe the structural changes and sequential microbial colonization and pectin loss that occur during microbe-assisted water retting. This study investigated the stages of microbial colonization, microbial interactions, and sequential degradation of pectic substances from jute bark under controlled and conventional water retting. The primary occurrence during water retting of bast fibres is the bacterially induced sequential breakdown of pectin surrounding the fibre bundles. The study also revealed that the pectin content of the jute stem significantly decreases during the retting process. These findings provide a strong foundation for improving microbial strains for improved pectinolysis with immense industrial significance, leading to a sustainable jute-based “green” economy.

The influence of residual pectin composition and content on nanocellulose films from ramie fibers: Micro-nano structure and physical properties

In this study, cellulose nanofibril (CNF) films from ramie fibers were prepared with different pectin compositions and contents, and the influence of residual pectin on the overall performances of CNF films was evaluated. There was no significant effect of the residual pectin composition on the properties of obtained CNF films. However, when the content of residual pectin was increased from 0.45 % to 9.16 %, the surface area and water absorption of CNF films were increased from 0.2223 to 0.3300 m2/g, and from 93.51 % to 122.42 %, respectively. Pectin covers the CNF surface and act as a physical barrier between the cellulose fibrils; thus the nanocellulose films with high pectin content will have a loose and porous structure, resulting in a high surface area and a high water absorption. Besides, with the residual pectin content decreasing from 9.16 % to 0.45 %, the UVA light transmittance and tensile strength of CNF films were increased from 30.6 % to 59.9 %, and from 37.67 to 100.26 MPa, respectively. After removal of amorphous pectins in CNFs, the low pectin containing CNFs are able to pack more compactly to form a strong and thin film. This paper provides guidance for the preparation of CNF films with different performance requirements.

Effect of treatment type of natural fibers on the rheological and micromechanical behavior of polyvinyl alcohol composites

AbstractThe viscoelastic and mechanical performance of sustainable raw materials on biodegradable matrices provide insights into how to develop and improve materials that contribute to the circular economy. Thus, we aim to evaluate the effect of conventional (acid or alkali) and dual (alkali/acid‐ultrasound) treatment on Agave fibers, as well as their rheological and micromechanical performance on polyvinyl alcohol (PVA)‐based composites. TGA results indicate that the treatments promote the removal of moisture, waxes, pectin, hemicellulose, and lignin from the fibers to different extents. PVA matrix containing modified fibers exhibits low viscosity, flux index, and critical shear values, indicating a high interaction and dispersion of the filler in the matrix. Furthermore, tensile tests and theoretical predictions of micromechanics‐based finite element analysis show evidence that the modified fiber type provides a different stress transfer ratio () than in the matrix, which changes Young's modulus values. The results indicate that Agave fibers modified by dual treatment are a useful filler to produce soft or stiff PVA composites when looking for potential applications in the mobility industry or other fields like the packaging.

Influence of single gummy component removal/retention on the physicochemical properties of fibrilia fiber and the reaction behavior of the other components in the degumming process

Although many degumming methods for fibrilia fiber have been established, the reaction priority of the gums and the influence of single gummy component removal/retention on the fiber property and the reaction behavior of the other components remain unclear. This study analyzed the above issues by the observing the change of fiber in microbial-mechanical ‘enzyme peeling’ and gas phase ozone treatment. Results showed that pectin removal could increase the fiber density significantly (∼60.3%) but would not cause damage to the fiber tenacity. The 2.5–4.5% pectin in untreated fiber could strongly restrict the removal of lignin and hemicellulose. Lignin had less influence on fiber density than pectin. The detailed composition of hemicellulose had a significant effect on fiber tenacity: the retention of xylan and mannan caused damage and benefit, respectively, to fiber tenacity. After the removal of 90.0% pectin and 23.0% hemicellulose, a deep delignification rate (>70.0%) could be obtained. The delignification rate of 70.0–80.0% was beneficial for the density decreasing and tenacity increasing of the fiber, while a delignification rate over 80.0% would cause the collapse of the cellulose structure and thus damage the fiber property.

Rare Earth Elements (REEs) Adsorption and Detoxification Mechanisms in Cell Wall Polysaccharides of Phytolacca americana L.

The cell wall (CW) is critical for the accumulation of heavy metals in metal-tolerant plants. Polysaccharides, the main component of the CW, contribute significantly to the immobilization of heavy metals. However, the mechanisms of rare earth elements (REEs) adsorption and detoxification by polysaccharides in the cell walls of Phytolacca americana L. (P. americana) remain unclear. In this work, we explored the binding sites of REEs and the modifications to polysaccharides in the cell walls of roots and leaves in P. americana, in order to elucidate the adsorption and fixation mechanism of REEs by the cell wall. Our findings indicated that up to 40.7% and 48.1% of cell-wall-bound REEs were present in the root and leaf pectin, respectively. The removal of pectin led to a 39.8% and 23.6% decrease in the maximum adsorption of REEs in the CW, suggesting that pectin was the main binding site for REEs in the cell walls of P. americana. Hydroxyl (-OH) and carboxyl (-COOH) groups in the cell wall interacted mainly with REEs ions under stress conditions, which played a key role in REEs binding. An obvious REEs fractionation was found during the various fractions of the CW, and all fractions of the root cell wall were enriched with HREEs, whereas all fractions of the leaf cell wall were enriched with LREEs. Moreover, P. americana modulated cell wall composition in reaction to REEs stress. In conclusion, cell wall pectin is the main binding site of REEs, and the functional groups on the cell wall play a significant role in the binding of REEs. At the same time, plants can control the selective adsorption and fixation of REEs by adjusting the composition of cell walls. This study offers valuable insights into the mechanisms of REEs adsorption and fixation in cell walls of P. americana, contributing to a theoretical basis for the bioremediation of REEs pollution.

Synthesis and characterization of nanocellulose from watermelon rinds and water hyacinth

Nanocellulose derived from cellulose, the abundant natural polymer, is used in various applications due to its superior chemical, mechanical and thermal properties along with good biocompatibility and biodegradability. This paper reports an investigation of the extraction of nanocellulose from two freely available natural precursors-watermelon rinds and water hyacinth leaves. Cellulose isolation was carried out through chemical methods, including acid and alkali treatments followed by bleaching. The chemical composition, percentage crystallinity and particle size were studied using various characterization techniques. FTIR spectra indicate the removal of hemicelluloses, pectin, and lignin resulting in the effective isolation of cellulose from both precursors. Results of XRD indicate a high concentration of Cellulose Nanocrystals (CNCs) in the treated sample. The FESEM and SEM-EDAX images also confirm the formation of CNCs. TGA and DSC results show excellent thermal stability for both CNCs. Investigations on the properties of a CNC-reinforced epoxy composite are also reported. Results indicate considerable improvement in the mechanical properties, thermal stability and thermal conductivity of the composites compared to the pristine polymer.

Solid-State Fermentation of Steam-Exploded Opuntia ficus-indica Cladodes Using Trichoderma reesei CCT-2768 for the Production of Cellulolytic Enzymes.

The sustainable development of the drylands, i.e., regions with limited availability of water, depends on the exploitation of the few biomass types that can thrive in such conditions, such as the Opuntia ficus-indica, a plant of the Cactaceae family. In the present study, the cladodes of O. ficus-indica were used as a substrate by the fungus Trichoderma reesei CCT-2768 for the production of cellulolytic enzymes through solid-state fermentation. Firstly, the extraction of the mucilage, soluble components of industrial interest, was evaluated. Temperature, water-to-biomass ratio, and time of mixture were varied using an experimental design and impacted, especially, the pectin removal. Then, the lignocellulosic residue was used for the production of enzymes; the effect of the water activity, biomass pretreatment, mineral supplementation, temperature, and inoculum size on the enzymatic production were investigated using two sets of experimental designs. The steam explosion pretreatment exposed the fiber to the microbial action and boosted the enzyme production, provided that the medium was supplemented with salts. This combination has improved the production of xylanase, CMCase, FPase, and polygalacturonase by 27, 62, 98, and 185%, respectively. The temperature of 35°C was determined as the optimal for the production of FPase, xylanase, and polygalacturonase, while no effect was observed on the production of CMCase and β-glucosidase. The optimization of the enzymatic production performed in this study can potentially provide a new application for the Opuntia biomass and improve the sustainable development of the drylands.

Application of selected chemical modification agents on banana fibre for enhanced composite production

Banana fibre is an agricultural waste that is obtained after harvesting the fruit at no additional cost. Banana fibre has major drawbacks in composite production, such as low interfacial bond strength between fibre and matrix when compared with synthetic fibre. This research aims to investigate the effect of selected chemical treatment on Banana fibre. The effects on morphological, mechanical and chemical properties were investigated using the Scanning electron microscope, computerized Tensile machine and FTIR Instrument. The chemicals applied in fibre treatment were Alkali (NaOH), Permanganate (KmnO4), and Acetylation. The results obtained showed that the surface roughness of the fibres was increased, and the hydrophilic nature of the fibres was reduced. There was a void introduction on the fibre’s surface, thereby providing better mechanical locking properties and reduction of water absorption tendency. The FT-IR spectroscopy results showed gradual changes consistent with the removal of pectin, lignin, hemicelluloses, oil, and waxes as chemical treatment progressed. Alkali chemical surface modification treatment of fibres enhanced the properties of the fibres by disrupting hydrogen bonding in their network structure. Permanganate chemical handling accounted for the formation of cellulose radicals with MnO-3 ion formation and fibre surface modification treatment using acetic acid enhanced the reduction of the hygroscopic nature of the banana fibres leading to increased dimensional stability. Mostly, the α cellulose contents of the fibre were increased from 63.40% to 82.23% at Silane chemical handling, while the other major components were reduced comparatively. Mechanical properties of the fibres such as tensile strength, flexural modulus, and percentage elongation improved with chemical treatment. This work also investigated the potential of using chemically modified Banana fibres (BPF) as reinforcement for polyester composites manufacture. The composites were produced by varying the BPF from 5 to 20 wt%. The density, mechanical properties and microstructure of the composite were examined, and there were remarkable improvements in the engineering properties of the composites. A 181.5% improvement in tensile strength and 56.63% increase in flexural strength was obtained over that of the unreinforced polyester.

A sustainable approach for cotton bioscouring: reuse of the pectate lyasecontaining treatment bath.

Enzymatic scouring of cotton has established itself (slowly) as a green alternative to alkaline scouring in the textile industry, mostly due to more environmentally friendly processing at lower pH and temperatures and its less aggressive action on the cotton fibers. However, among other limitations, enzyme costs have contributed to impeding its wide acceptance and use. For the first time, in this study, the recycling of the bioscouring bath was evaluated, unlike most current bioscouring that is performed using fresh enzyme solution. Bioscouring of raw knitted cotton fabric was carried out for 30min with a commercial pectinase (BioPrep® 3000L) at 55°C and pH 8.5. About 89% of the recovered pectate lyase-containing scouring bath was completed with 11% of fresh enzyme solution and reused in a new bioscouring process under the same conditions. Up to ten reuse cycles were possible maintaining the level of pectin removal and without significant loss in quality of subsequent dyeing. A detailed analysis of the pretreated fabrics is presented. Reusing the scouring bath, reducing the intensive consumption of input materials (enzyme, water, and chemicals) and wastewater generation can be possible, making bioscouring a more attractive and sustainable technique. The process demonstrated is promising and its industrial application is feasible.

Experimental investigation on influence of selected chemical treatment on banana fibre

This research examined the effect of selected chemical treatment on Banana fibre. The morphological, mechanical and chemical properties effects were investigated using the Scanning electron microscope, computerized Tensile machine and FTIR Instrument. The chemicals applied in fibre treatment were Alkali (NaOH), Permanganate (KmnO4), and Acetylation. The results obtained showed that the surface roughness of the fibres was increased, and the hydrophilic nature of the fibres was reduced. There was a void introduction on the surface of the fibre thereby providing better mechanical locking properties and reduction of water absorption tendency. The results of FT- IR spectroscopy showed gradual changes consistent with the removal of pectin, lignin, Hemicelluloses, oil, and waxes as chemical treatment time increased by comparing the changes in the intensity of the carbonyl-H, OH, CC−H, C−H and CO stretch. It also showed that the number of hydroxyl groups on the fibre surface decreased as treatment time increased. Alkali chemical surface modification treatment of fibres enhanced the properties of the fibres by disrupting hydrogen bonding in their network structure. Permanganate chemical handling accounted for the formation of cellulose radicals with MnO−3 ion formation and fibre surface modification treatment using acetic acid enhanced the reduction of the hygroscopic nature of the banana fibres leading to increased dimensional stability. Mostly, the α cellulose contents of the fibre were increased from 63.40% to 82.23% at Silane chemical handling, while the other major components were reduced comparatively. Mechanical properties of the fibres such as tensile strength, flexural modulus, and percentage elongation increased after chemical treatment. There was an increased loss in weight of fibres with increased chemical modification time which enhanced the mechanical properties of fibre strands.

Structural changes of lignin-carbohydrate complexes (LCCs) from Chinese quince fruits during the sequential fractionation of pectic and hemicellulosic polysaccharides

Chinese quince (Chaenomeles sinensis) fruits offer a potential source of pectin and hemicellulose. However, the existence of lignin-carbohydrate complexes (LCCs) can negatively impact the extraction of pectin and hemicellulose. In this work, LCCs were sequentially fractionated from Chinese quince during the removal of pectin and hemicellulose. The structures of LCCs were characterized by HPAEC, FT-IR, GPC, Py-GC/MS, TGA and 2D HSQC NMR. The results showed that the carbohydrate content and molecular weight of LCCs was found to be changed significantly after the removal of hemicellulose (KSH). The lignin in Björkman LCCs was found to be linked mainly to galactan and fructan, whereas the lignin LCC-AcOHs was found to be linked mainly to arabinan after the removal of KSH. The isolation of carbonate-soluble pectin (NSP) increased thermal stability of Björkman LCC fraction, however, the isolation of chelator-soluble pectin (CSP) increased the thermal stability of LCC-AcOHs. The S/G ratios of LCC-AcOHs increased and large amounts of S-type lignin released during sequential fractionation of pectin and hemicellulose. These results will be beneficial for understanding the mechanisms of pectin and hemicellulose isolation, thereby facilitating the potential application of Chinese quince as a valuable natural resource for food and other industries.

The role of polysaccharides functional groups in cadmium binding in root cell wall of a cadmium-safe rice line

Exploring the mechanism of cadmium (Cd) accumulation in Cd-safe rice lines is beneficial for ensuring rice safety. D62B, a Cd-safe rice line, accumulates less than 0.2 mg Cd kg-1 in the brown rice due to strong capacity of Cd retention in the roots, and the root cell wall (RCW) polysaccharides play important roles. However, specific underlying mechanism of Cd binding on the polysaccharides is little known. In this study, the role of polysaccharides, especially pectin and hemicellulose 1 (HC1), in RCW of D62B was investigated by adsorption experiments and Fourier Transform Infrared Spectroscopy (FTIR) analysis compared with a common rice line (Luhui17). Cadmium was adsorbed on RCW of two rice lines by a multilayer and inhomogeneous chemisorption way with the force of ion transfer or exchange. Cadmium was adsorbed on RCW rapidly at first stage with the limit of internal and external diffusion, and gradually reached saturation. With the removal of pectin, the Cd adsorption rate, maximum Cd adsorption amount and the shift degree of carboxyl groups in the RCW of D62B sharply decreased, which showed advantages compared with Luhui17. Sequential removal of HC1 further decreased the maximum Cd adsorption amount and the shift degree of hydroxyl groups. The results showed that more available functional groups, especially carboxyl groups in pectin and hydroxyl groups in HC1, contributed to Cd immobilization within the RCW of Cd-safe rice line, thus limiting Cd translocation to the shoot and reducing Cd accumulation in the brown rice.

Antimicrobial activity of bleached cattail fibers (Typha domingensis) impregnated with silver nanoparticles and benzalkonium chloride

AbstractTypha domingensis (Cattail) fiber is a significant natural resource, abundant in cellulose. The study reports the useful utilization of T. domingensis fiber for physicochemical impregnation of silver nanoparticles and benzalkonium chloride, in the development of a material with antimicrobial activity. The fibers were pre‐treated with alkaline hydrogen peroxide (bleaching) for partial removal of lignin, pectin and waxes. Subsequently treated in a solution of different concentrations of benzalkonium chloride and Tollens' reagent. The new materials obtained were carefully investigated for their structure and thermal stability, morphology and susceptibility to antimicrobials (Staphylococcus aureus, Escherichia coli, Salmonella typhimuruim, and Salmonella enteritidis). Fourier transform infrared spectra showed the presence of benzalkonium chloride. The morphology analysis showed the silver nanoparticles on the surface of the bleached fibers. The susceptibility profile to antimicrobials was confirmed by the formation of inhibition halos (≅11.26 mm). Based on the properties of the materials obtained, it can be concluded that the modified cattail fibers have the potential to be used as a functional filler, or coating, in the development of antimicrobial composites.

Oil and pectin extraction from citrus paradise(grape) peels: A case of response surface optimization

This work reflects the extraction process of oil and pectin from grape peels using a response surface method in which a central composite rotatable design of 25 and 35 was used for the two extractions. Output temperatures (80–100°C) and heating times (5–9 hours) were used for oil extraction, while (80 -100oC) and heating times (20 – 60 minutes) and a pH of extract (1.0 – 3.0) were selected for pectin removal. Oil yield ranged from 7.90 - 15.30%, while pectin yield ranged from 19.90 – 35.70%. A maximum oil yield of 15.30% was obtained at a temperature of 90oC at a heating time of 9.0 hours, while a maximum yield of pectin of 35.70% was obtained at a pH of 2.5, 95oC temperature and 50 minutes heating time. The optimum value for oil production was 15.63% at an average temperature of 99.64oC and heating time of 8.99 hours, while the average value of pectin yield was 38.01% at an output temperature of 94.00oC, the period release time of 58.00 minutes with a pH of 2.00. The deviation between the experimental and predicted values was low and not significant. All processing conditions have important impacts on the extraction of oil and pectin from grape peels.

Impact of processing on the functionalization of pumpkin pomace as a food texturizing ingredient

In the context of side-stream valorization, this study aimed to gain insight into the functionalization of industrially-generated pumpkin pomace as texturizing ingredient. Given the matrix complexity of pumpkin pomace, composed of crushed peels, seeds and mesocarp, this study focused on the impact of different sample preparation, as well as mechanical processing, on the microstructural and rheological properties of pumpkin pomace suspensions. Pumpkin pomace suspensions (4% w/w) possessed a solid-like behavior, demonstrating the potential for structure build-up. The application of heat during sample preparation (85°C, 30 min) significantly increased the storage modulus of the pumpkin pomace-derived suspensions, which was found to be related to an increased swelling volume of the suspended particles. Moreover, a combination of partial pectin removal and high pressure homogenization at 80 MPa led to improved network structure formation, as obvious from an increased storage modulus. These results are highly useful as scientific basis for exploring the texturizing potential of pumpkin pomace with minimal processing or conventional preparation methods (e.g. by heat treatment).

Chemical functional groups of extractives, cellulose and lignin extracted from native Leucaena leucocephala bark

Bark from trees is considered a worthless raw material. However, this resource could be economically beneficial if utilized efficiently due to its rich chemical compounds. In this study, an ethanol toluene-soluble extractive, alpha-cellulose and lignin obtained from Leucaena leucocephala bark were characterized to determine their chemical functional groups. Based on FTIR spectral analysis, the results indicated that the bands of the functional groups of the extractive from the original bark remain unchanged; however, the absorbance intensity was found to be weaker in the group frequency and fingerprint regions. Removal of extractive, pectin, hemicellulose and lignin from the bark indirectly increased the strong absorbance intensity of cellulose. Broad peaks of OH stretching found in all spectra were assigned to the presence of phenolic OH and aliphatic structures for extractive and aromatic structures of lignin. It was revealed that aromatic functional groups were mainly found in the extractive, while water, carbonyl and ether were the dominant groups in cellulose, and methyl, methylene, carbonyl and carboxyl groups were enriched in lignin.Graphic abstract

Synergism between Cutinase and Pectinase in the Hydrolysis of Cotton Fibers’ Cuticle

Scouring is one of the initial steps in the processing of natural textile fibers (e.g., cotton), performed to remove waxes and pectins, together with spinning oils and other impurities of the plant cell cuticle. Traditional chemical bleaching with boiling NaOH led to harsh removal of the entire fabric’s cuticle waxy layer accompanied by an unwanted alkaline waste. Extracellular lytic enzymes such as lipases, cellulases and pectinases play an essential role in host plant-pathogen interactions. They degrade the plant cuticle and tissue and enable pathogen invasion. Such enzymes, specifically cutinase and pectinase, have been considered potential bio-scouring agents to degrade the cotton fabric cuticle’s outer layer at low temperature and alleviate environmental pollution. In this work, the combined effect of cutinase, pectin lyase, or polygalacturonase on the scouring of cotton fabrics was studied using evaporative light-scattering reverse-phase HPLC and GC-MS analysis of the reaction components, and measuring changes in the cotton fabrics’ properties. The traditional method of cotton fabrics’ scouring with NaOH resulted in decreased pectin content and increased cellulose fibers accessibility, evaluated by specific staining. Treating the cotton fibers’ cuticle with cutinase led to the acidification of the reaction mixture, a decrease in enzyme-specific activity, and elevation in hexadecanoic acid and octadecanoic acids in the reaction fluid. These two saturated fatty acids are the main wax constituents of raw cotton fabrics, identified using GC-MS after dichloromethane reflux overnight. Treating cotton fabrics with each of the three enzymes, cutinase, pectin lyase, or polygalacturonase, increased their pectin removal, as measured by high concentrations of D-galacturonic acid and other pectin constituents in the reaction fluid. A synergistic effect was found in the combined treatment of cutinase and pectin lyase in the hydrolysis of the cotton fibers’ cuticle. This effect was expressed in high water absorbency of the treated fibers, increased fabric weight loss and sharp elevation of a cutin and pectin monomer’s related peaks (retention time [RT] = 4.1 min and 2.9, 4.5 min, respectively). A model was suggested for the synergistic action between cutinase and pectin lyase. It assumes that the cuticle’s digestion by cutinase results in the enlargement and formation of outer layer micropores, which enables the rapid penetration of pectinase into the inner pectin layer.

The predominant role of pectin in binding Cd in the root cell wall of a high Cd accumulating rice line (Oryza sativa L.)

Cell wall (CW) plays an important role in Cd accumulation in roots of metal-tolerant plants, including rice. The role of CW polysaccharides, especially pectin, in binding Cd in roots of a high Cd accumulating (HA) rice line of Lu527-8 and a non-high Cd accumulating (NHA) rice line of Lu527-4 was investigated in this study. About 59%–63% of Cd in roots of the two rice lines was bound to CWs, indicating that CW was the main site for Cd accumulation in roots of the two rice lines. Cd adsorbed on the root CWs of the HA was 1.1–1.2 times more than that of the NHA, demonstrating the root CWs of the HA showed greater Cd binding ability. Cd exposure induced more Cd accumulation in pectin and hemicellulose in the HA. In particular, up to 65% of Cd accumulation in root CWs of the HA was observed in pectin. The removal of pectin lead to a 50% decrease for the amounts of Cd adsorption on root CWs of the HA, indicating that pectin was the major binding site for Cd in root CWs of the HA. The HA showed greater pectin methylesterase activities, resulting in lower degree of pectin methylesterification along with more low-methylesterified pectins in root CWs than the NHA. The more accumulation of low-methylesterified pectins in CWs induced by Cd contributed greatly to the high Cd accumulation in roots of the HA rice line of Lu527-8.