Removal Of Pectin Research Articles

Chlorine-free extraction of cellulose from rice husk and whisker isolation

Abstract This work reports the isolation of cellulose whiskers from rice husk (RH) by means of an environmental friendly process for cellulose extraction and bleaching. The multistep process begins with the removal of pectin, cutin, waxes and other extractives from rice husk, then an alkaline treatment for the removal of hemicelluloses and lignin, and a two-step bleaching with hydrogen peroxide/tetra-acetylethylenediamine (TAED), followed by a mixture of acetic and nitric acids, for further delignification of the cellulose pulp. The techniques of infrared absorption spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), modulated differential scanning calorimetry (MDSC) and X-ray diffraction (XRD) showed that the overall process is adequate to obtain cellulose with high purity and crystallinity. This cellulose was submitted to sulfuric acid hydrolysis with the aim to isolate the whiskers. They showed the typical elongated rod-like aspect as revealed by transmission electron microscopy (TEM) and atomic force microscopy (AFM).

A Two-Step Chemical Process for the Extraction of Cellulose Fiber and Pectin from Mulberry Branch Bark Efficiently

In this work, a two-step method for the extraction of pectin and cellulose fiber from mulberry branch bark, a by-product of sericultural industry, was described. The method was based on the acid extraction of pectin and subsequently alkali treatment for obtaining cellulose fibers. The obtained pectin was high purity with the total galacturonic acid content of 85.46% ± 2.76% and the degree of esterification of 71.13% ± 1.67%. The chemical composition analysis, FTIR spectroscopy, XRD and TG analysis were used to characterize the cellulose fiber at different processing stages. After the two-step chemical process, the cellulose content was increased from 37.38% in original bark to 92.60% in cellulose fiber. The FTIR spectra revealed the removal of pectin, hemicelluloses and lignin from the bark by acid extraction and alkali treatment. The XRD and TG results indicated that the obtained cellulose fibers were with the increased crystallinity and thermal stability, whose crystallinity and degradation temperature were 86.36% ± 5.56% and 355 °C, respectively. This work may provide a new approach for high utilization of mulberry branch bark.

A peroxisomal ABC transporter promotes seed germination by inducing pectin degradation under the control of ABI5

Seed dormancy is essential for most plants to control the timing of germination. In Arabidopsis thaliana, PED3 is a single-copy gene encoding an ATP-binding cassette transporter that is required for peroxisomal fatty acid beta-oxidation. PED3 is involved in the import of several biologically important molecules into the peroxisome, including very-long-chain fatty acids associated with the breakdown of seed-reserve lipids, and precursors of auxin and jasmonic acid. The germination of ped3 mutants is significantly impaired, suggesting that PED3 regulates dormancy and germination. A transcriptome analysis revealed that many genes containing the core motif of the ABA responsive element (ABRE) in their promoter regions, and the ABA insensitive 5 (ABI5) transcription factor that binds to ABRE, are abnormally up-regulated in imbibed ped3 seeds. Expression of polygalacturonase inhibiting proteins (PGIPs) is also up-regulated specifically in ped3 after imbibition. By contrast, the ped3 abi5 double mutant does not show any of these expression patterns. The results indicate that the abi5 mutation normalizes PGIP expression and rescues the impaired germination phenotype of the ped3 mutant. PGIPs are known to act as inhibitors of polygalacturonases that degrade pectin. The amount of PGIP1 transcript regulates the timing of radicle protrusion. The impaired germination of ped3 could also be rescued by removal of pectin from the seed coat using exogenous polygalacturonase or acidic conditions. Overall, our results suggest that PED3, a peroxisomal ABC transporter, promotes seed germination by suppressing PGIPs under the control of ABI5.

Pectins influence microfibril aggregation in celery cell walls: An atomic force microscopy study

Atomic force microscopy (AFM) was used to image the microfibrilar network of celery parenchyma cell wall material (CWM), before and after each step in the selective extraction of pectins and hemicelluloses. The images collected were subjected to image analysis and the diameters of the cellulose microfibrils were measured following each step in the extraction process. Not only was an increase in the mean size of the microfibrils observed as the pectins were selectively removed, but an increase in the proportion of large to small microfibrils was also observed. This suggests that removal of the pectic matrix not only results in the swelling of existing microfibrils, but also removal of pectins would enable the microfibrils to move closer together within the cell wall, and hence have a greater tendency to self-associate and form aggregates.

Micro-scale anaerobic digestion of point source components of organic fraction of municipal solid waste

The fermentation characteristics of six specific types of the organic fraction of municipal solid waste (OFMSW) were examined, with an emphasis on properties that are needed when designing plug-flow type anaerobic bioreactors. More specifically, the decomposition patterns of a vegetable (cabbage), fruits (banana and citrus peels), fresh leaf litter of bamboo and teak leaves, and paper (newsprint) waste streams as feedstocks were studied. Individual OFMSW components were placed into nylon mesh bags and subjected to various fermentation periods (solids retention time, SRT) within the inlet of a functioning plug-flow biogas fermentor. These were removed at periodic intervals, and their composition was analyzed to monitor decomposition rates and changes in chemical composition. Components like cabbage waste, banana peels, and orange peels fermented rapidly both in a plug-flow biogas reactor (PFBR) as well as under a biological methane potential (BMP) assay, while other OFMSW components (leaf litter from bamboo and teak leaves and newsprint) fermented slowly with poor process stability and moderate biodegradation. For fruit and vegetable wastes (FVW), a rapid and efficient removal of pectins is the main cause of rapid disintegration of these feedstocks, which left behind very little compost forming residues (2-5%). Teak and bamboo leaves and newsprint decomposed only to 25-50% in 30d. These results confirm the potential for volatile fatty acids accumulation in a PFBR's inlet and suggest a modification of the inlet zone or operation of a PFBR with the above feedstocks.

Effect of pre-treatment of Luffa fibres on the structural properties

Recently, the use of lignocellulosic fibres to reinforcing composite has received an increased attention. However, lack of good interfacial adhesion makes important the treatment of raw materials. Chemical treatment prepared the raw material to be useful by elimination of gummy and waxy substances. In this study, the Luffa fibres were treated by tow methods: alkali treatment and mixed treatment (sodium hydroxide and hydrogen peroxide). The effect of these treatments on the structure of fibres was showed using SEM and XRD (X-Ray Diffraction) analysis. The SEM results revealed that both treatments resulted in a removal of lignin, pectin and hemicellulose substances, and change the characteristics of the surface topography. The XRD analysis shows the increase of crystallinity index by many treatment conditions. We find that the alkali treatment (120 °C; 3 h; 4% NaOH) shows a good cleaning and the higher crystallinity index of treated fibres. It is also interesting to note that mixed treatment can change the Luffa fibres from mat structure to fibrils structure.

Study on microbe retting of kenaf fiber

Retting is the predominant problem in the application of kenaf fiber in high-grade products. While the traditional retting method is water retting, that is, the harvested bast kenaf is immersed in natural water (rivers or tanks) in which indigenous bacteria colonize noncellulosic materials in an anaerobic process resulting in severe environmental problems and low-grade fiber, therefore it is inevitable to seek for a pollution-free or little-pollution retting method. With the more application of biotechnology in textile industry, the more biology-treatments have been researched recently. So microbe retting was employed in this work. The fungus strain was isolated from the river in which kenaf fiber was retted, then microbe retting was performed with this fungus. Substrate species, the initial pH of the culture medium, cultivation temperature, retting time and inoculum size are involved in the experiments and the evaluation of retting is based on the residual gum content in retted kenaf fiber. As a result, the removal of pectin in microbe retting of kenaf is 91.31% under the optimal retting conditions. In addition, the effective retting fungus is also observed with microscope as one kind of filamentous epiphyte.

Wax removal for accelerated cotton scouring with alkaline pectinase

A rational approach has been applied to design a new environmentally acceptable and industrially viable enzymatic scouring process. Owing to the substrate specificity, the selection of enzymes depends on the structure and composition of the substrate, i.e. cotton fibre. The structure and composition of the outer layers of cotton fibre has been established on the basis of thorough literature study, which identifies wax and pectin removal to be the key steps for successful scouring process. Three main issues are discussed here, i.e. benchmarking of the existing alkaline scouring process, an evaluation of several selected acidic and alkaline pectinases for scouring, and the effect of wax removal treatment on pectinase performance. It has been found that the pectinolytic capability of alkaline pectinases on cotton pectin is nearly 75% higher than that of acidic pectinases. It is concluded that an efficient wax removal prior to pectinase treatment indeed results in improved performance in terms of hydrophilicity and pectin removal. To evaluate the hydrophilicity, the structural contact angle (theta) was measured using an auto-porosimeter.

Optimized techniques for the extraction of grape allergens appropriate for in vivo and in vitro testing and diagnosis

Standardized allergen extracts are needed for diagnosis and therapy purposes. For grapes, standardization is hampered by low protein and high tannin and pectin concentrations. The aim of the current study was to develop an optimized method for the extraction of grape proteins and possibly extend this to other fruits. Several existing or modified extraction methods were compared by means of protein concentration determination, SDS-PAGE, immunoblotting and radioallergosorbent test (RAST). An optimized extraction protocol was obtained in which we combined a high concentration of plant tissue, a concentrated, enriched and neutral buffer able to remove sugars and keep proteins soluble and a bivalent buffer for pectin removal. Both the quantitative (protein concentration) and qualitative parameters (SDS-PAGE protein patterns and IgE reactivity) were compared to standard protocols and commercial extracts used as diagnostic tools in the clinical practice. This method proved to be the most efficient mainly compared to the standard Björksten protocol in extracting the low molecular weight proteins, including the major grape allergen (lipid transfer protein, Vit v 1). It proved to be an easy, low cost and reproducible method proposed to prepare grape extracts that could replace the commercially available ones, used for diagnosis and possibly extend the method to other fruits especially in extracting LTPs.

Optimizing bioscouring condition of cotton knitted fabrics with an alkaline pectinase from Bacillus subtilis WSHB04-02 by using response surface methodology

This present study was undertaken to find optimum conditions of pH, temperature, incubation time and enzyme concentration for bioscouring of cotton knitted fabrics with an alkaline pectinase isolated from Bacillus subtilis WSHB04-02 by use of response surface methodology (RSM). A central composite design was used as an experimental design for the analysis of the allocation of treatment combination. A second-order polynomial regression model was fitted and was found adequate with a determination coefficient R 2 of 0.9844 ( P < 0.001). The effect of pH was the most significant factor influencing cotton bioscouring and no significant interactions between different factors were found. Estimated optimum parameters were as follows: pH 9.1, temperature 57 °C, incubation time 1.25 h and pectinase concentration 1.0 g/l. Under these conditions, a desired pectin removal percentage companied with adequate wettability was reached. In addition, a boiling water pretreatment of 30 min before enzymatic scouring was found to be useful for subsequent pectinase degradation due to the improvement of the accessibility of pectinase to the pectins in cotton fibers.

Intercellular Adhesion Strengthening As Studied through Simulated Stress by Organic Acid Molecules in Potato (Solanum tuberosum L.) Tuber Parenchyma

Intercellular adhesion in some parenchyma becomes strengthened in response to stress. The present study provides an approach to investigate this phenomenon (usually attributed to pectin methyl esterase and binding of Ca(2+) and/or rhamnogalacturonan-II-borate) through reliable stress simulation by probing organic acid molecules in potato tuber parenchyma. Short-chain monocarboxylic acids induce consistent intercellular adhesion strengthening (3.8-5.3 newton) at pH >or= 3 < pK(a), where pectin methyl esterase activity and Ca(2+) or borate binding are limited, and vice versa at pH > pK(a) with a strength of 1.4-2.0 newton as compared to 0.3-0.4 newton for the nonincubated control. Strengthening of intercellular adhesion is characterized by prominent staining of pectin and protein and immunogold labeling of pectin in the cell wall and the middle lamellar complex, particularly after boiling. Pectin confers strengthening to the primary cell wall, as reflected by: (i) prominent immunogold labeling following boiling; and (ii) puncturing macerated cells by starch gelatinization pressure after enzymatic pectin removal.

Production of Cellulase-Free Polygalacturonase Preparation by Sclerotium rolfsii for Bioscouring of Cotton

SUMMARY Cultivation media for the production of both a cellulase containing and a cellulase-free polygalacturonase (PG) preparation by a highly productive strain of Sclerotium rolfsii (CBS 350.80) were developed. These enzyme preparations both contained a PG activity higher than 500 IUmL−1 and were applied in a bioscouring sequence of knitted cotton at various activity levels. The progress of bioscouring was evaluated by weight loss, water absorption time and determination of residual pectin. Released sugars have been determined and compared to bioscouring effects. No significant differences among the tested preparations were obtained for water absorption and pectin removal. However, considerably higher weight losses were observed for the preparations containing cellulase. A minimal enzyme dosage of 100 IUg−1 cotton was necessary to achieve suitable scouring results under the applied conditions.

Characterization of bioscoured cotton fabrics using FT-IR ATR spectroscopy and microscopy techniques

The effects of bioscouring were investigated by characterizing the chemical and physical surface changes of cotton fabrics using a purified pectinase enzyme from Bacillus subtilis strain WSHB04-02. Fourier-transform infrared (FT-IR) attenuated total-reflectance (ATR) spectroscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM) techniques were employed. FT-IR ATR spectroscopy provided a fast and semi-quantitative assessment of the removal of pectins and/or waxes on the cotton surface by comparing the changes in intensity of the carbonyl peak induced by HCl vapor treatment at around 1736cm−1. The bioscoured surface could be clearly distinguished from those of untreated and alkali-treated cotton fibers using a combination of SEM and AFM. The images produced using these techniques revealed that the surface morphography and topography of the cotton fibers were shaped by the etching action mode of pectinases during bioscouring. These findings demonstrated that AFM is a useful supplement to SEM in characterizing cotton surfaces.

The Mode of Action of Sodium Hypochlorite in the Cleaning Process

The action of sodium hypochlorite (NaOCl) solution in the cleaning of alumina (Al2O3) particles fouled with bovine serum albumin (BSA) or pectin was studied as a function of pH. The efficacy of NaOCl in the cleaning process was evaluated in the pH region where OH- alone exerted no significant action on BSA or pectin removal. The efficiency and the rate of the removal of BSA or pectin increased with increasing available chlorine concentrations and pH. The pH dependence of the efficacy of NaOCl could be explained on the basis of the equilibrium between undissociated hypochiorous acid (HOCl) and dissociated hypochlorite ion (OCl-). The efficacy of NaOCl in the removal of BSA or pectin depended on the concentration of OCl-, but not on HOCl. Size-exclusion chromatographic analysis showed that BSA molecules were partially decomposed by the action of NaOCl, whereas no significant variation in the molecular weight of pectin molecules took place. The difference between the actions of OCl- in the removal of BSA and pectin could probably be ascribed to the reactivity of OCl- with their molecules. It could be concluded that the concentration of OCl- was a major factor determining the actual NaOCI concentration required for an efficient cleaning treatment.

Advances in pectin and pectinase research. * Voragen F, Schols H and Visser R. eds. 2003. The Netherlands: Kluwer Academic Publishers. 145 (hardback). 491 pp.

Advances in pectin and pectinase research. * Voragen F, Schols H and Visser R. eds. 2003. The Netherlands: Kluwer Academic Publishers. 145 (hardback). 491 pp.

Removing Pectin and Lignin During Chemical Processing of Hemp for Textile Applications

Pectin and lignin are both very important noncellulosic substances occurring in hemp fibers. The main task in preparing hemp fibers for textile applications is to remove these noncellulosic substances without damage to the fiber cellulose. Pectin and lignin in hemp before and after chemical processing are characterized by infrared spectroscopy. The influence of chemical processes, fiber regions, and alkaline boiling parameters on lignin and pectin removal are investigated in this paper. The results indicate that the alkaline boiling process is effective for removing pectin and lignin. There is no residual pectin in the fibers after the alkaline treatment, but there is a residual level of lignin. The concentration levels of both sodium hydroxide and sodium sulphite have significant effects on lignin removal, and there are variations in lignin properties and accessibility from the lower to the upper regions of the hemp stem.

Influence of the carbon source on production of cellulases, hemicellulases and pectinases by Trichoderma reesei Rut C-30

The growth and enzyme production by Trichoderma reesei Rut C-30 using different lignocellulosic materials as carbon source were investigated. Cellulose, sugar beet pulp and alkaline extracted sugar beet pulp (resulting in partial removal of hemicellulose, lignin and pectin) or mixtures thereof were used as carbon sources. It was found that endoglucanase and endoxylanse activities were produced throughout the cultivations, whereas α-arabinosidase was induced late during the cultivation. The highest amounts of endoglucanse, could be measured when T. reesei Rut C-30 was grown on cellulose or cellulose containing mixtures. Endoxylanase was produced on all substrates, but the presence of cellulose was favourable for the production. Polygalacturonase activity could be measured at high varying levels throughout the cultivations, except during growth on cellulose. The varying levels might originate from the production of different isoenzymes of polygalacturonase.

Degumming of ramie: the role of the individual constituents of the gummy material

The stepwise removal of the components of gummy material found on ramie fibres was used to determine the effects of the individual constituents on the whiteness and yellowness indices of the fibres. The main components were found to be hemicellulose, pectin and lignin and these had the greatest effect on the whiteness and yellowness indices. A spectroscopic method for assessing the hemicellulose and pectin content of the degumming bath was investigated and found to be comparable to the results of chemical analysis. The spectroscopic method was used to study the removal of hemicellulose and pectin continuously during degumming, and the data obtained were used to calculate rate constants for the degumming process.

Cellulose microfibrils from potato tuber cells: Processing and characterization of starch-cellulose microfibril composites

The ultrastructure and morphology of potato (Solanum tuberosum L.) tuber cells were investigated by optical, scanning, and transmission electron microscopies. After removal of starch granules, pectins and hemicelluloses were solubilized under alkaline conditions. The alkaline insoluble residue consisted mainly of primary cell wall cellulose, which can be disintegrated under shearing to produce a homogenized microfibril suspension, as reported in a previous work.40 Composite materials were processed from this potato cellulose microfibril suspension, gelatinized potato starch as a matrix and glycerol as a plasticizer. After blending and casting, films were obtained by water evaporation. The mechanical properties and water absorption behavior of the resulting films were investigated, and differences were observed depending on the glycerol, cellulose microfibrils, and relative humidity content. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 2080–2092, 2000

Gastrointestinal or simulated in vitro digestion changes dietary fibre properties and their fermentation

This study evaluated the effect of digestion on the chemical and physicochemical characteristics of dietary fibre and on its behaviour during fermentation. Three dietary fibre sources (wheat bran, barley bran and beet fibre) were recovered from ileal cannulated pigs after in vivo digestion and prepared by in vitro enzymatic treatment simulating digestion. Raw substrates and fibre residues were analysed for their chemical and physicochemical properties as well as their potential fermentation by human colonic bacteria. In vitro and in vivo treatments led to insoluble residues, enriched in cell wall polysaccharides, with similar cell wall sugar composition and physicochemical properties. Degradations of cell wall polysaccharides with losses of sugar residues occurred mainly after in vivo digestion, especially for pectins from beet fibre and β-glucans from barley bran. Solubilisation of β-glucans removed highly fermentable substrates for further fermentation. For beet fibre, removal of pectins led to increased hydration properties and faster fermentation of cell-wall polysaccharides. Enzymatic treatment simulated correctly the passage of fibre through the digestive tract, modifying the cell-wall matrix and predisposing the fibre to further fermentation. © 1998 SCI.