Presence Of Pectin Research Articles

Formation of heated whey protein isolate-pectin complexes at pH greater than the isoelectric point with improved emulsification properties

In this study, heated whey protein isolate and pectin complexes (HCPX) formed at pH > isoelectric point (pI) were used to stabilize oil-in-water emulsions containing 5% oil and 1.5% (wt%) protein at pH 5.5. The effects of pectin concentration and heating temperature on emulsification and emulsion stabilization properties were determined. The HCPX were produced by heating mixed 3% (wt) whey protein isolate and pectin (0.1 or 0.3 wt%) at pH 6.2 and 75 or 85°C for 15 min. Aggregate sizes significantly increased with increasing heating temperature but decreased with the addition of pectin. The HCPX became more negatively charged with increasing pectin concentration; however, the effect of heating temperature was significant only at 0.1% pectin. Unheated complexes and HCPX successfully adsorbed at the oil-in-water interface and improved the emulsification properties as shown by higher negative charge and smaller droplet sizes. Despite the presence of pectin, rheological properties of the emulsions were not significantly different. All complexes showed increased emulsion stability; however, HCPX made at 85°C formed emulsions that were the most stable against creaming and heating.

Preparation and characterization of zein/pectin-based phytosterol nanodispersions and kinetic study of phytosterol release during simulated digestion in vitro

The purpose of this study was to fabricate zein/pectin-based stigmasterol nanodispersions and improve their stability. The optimal condition of pectin/zein ratio of stigmasterol nanodispersions was 1:10. In this condition, the average particle diameter, Zeta-potential, encapsulation efficiency and loading amount of nanodispersions were 584.40 ± 69.55 nm, −38.32 ± 0.23 mV, 84.96 ± 3.28% and 15.45 ± 0.59 g/100g, respectively. The scanning electron microscope (SEM) and differential scanning calorimetry (DSC) results showed that stigmasterol and zein were successfully encapsulated by pectin which formed elastic network gel on the outside of the particles. With presence of pectin, the stability of the nanodispersions in different environmental and simulated digestion condition had been improved.

Relations between digestibility and structures of pumpkin starches and pectins

Pumpkin has human nutritional benefits, arising from its high content of starch and of dietary fibres such as pectins. Pectin has been found to slow starch digestion in digesta, which is related to the reduction of propensity towards diet-related diseases such as diabetes, but whether un-extracted pectin could influence in vitro digestibility of in situ starch in vegetable is unknown. In this paper, the molecular structures of pectin and starch from 13 commercial pumpkin varieties were characterized (using HPLC and size-exclusion chromatography), and the in vitro digestion kinetics of the boiled flour measured. The structural and kinetic data were fitted to models, and correlation analysis applied to the resulting parameters to find the factors influencing the digestibility. It was found that (1) a particular structural feature of pumpkin starch was the high proportion of long amylopectin chains, (2) pumpkin pectins exhibited wide diversity in molecular structure, (3) the in vitro digestibility of pumpkin flour parameters correlated with structural parameters of both pectin (degree of esterification) and starch (average hydrodynamic radius). These results showed that both macromolecules affect pumpkin flour digestibility, and the presence of pectin as a key component of cell wall materials contribute to the provision of a barrier between amylase and starch. Unlike the digestion of pure starch, where the starch structure is the major determinant in digestibility, the digestion of pumpkin flour depends also on the complex network of pumpkin polysaccharides.

Efficient production of biodiesel by using a highly active calcium oxide prepared in presence of pectin as heterogeneous catalyst

The cation binding ability of pectin was explored for the preparation of a highly active CaO catalyst for soybean oil transesterification. The catalyst was prepared by the precipitation method using Na2CO3 and Ca(NO3)2 in the presence of pectin followed by calcination. The best catalyst, CaP-600, was prepared at 600 °C and was characterized by FTIR, TGA, BET, CO2-TPD and powder X-ray diffraction (PXRD). CaP-600 was characterized as CaO containing carbonaceous materials left from pectin combustion. At only 1 wt% CaP-600 loading, biodiesel conversion reaches 99% after 4 h with a methanol:oil = 7:1 M ratio. Importantly, the calcium content in the produced biodiesel was only 0.7 ppm, which implies a satisfactory compliance with the ASTM D6751 and EN 14,214 standards. To the best of our knowledge, this is the best CaO catalyst reported for biodiesel production in terms of efficiency and amount of calcium leached. For comparison, CaO prepared in the absence of pectin showed poor catalytic activity in the optimized reaction conditions, demonstrating that the presence of the biopolymer prior to the calcination step is crucial for the catalytic performance of the CaO particles. Possible rationales for the biopolymer role are discussed.

Stem anatomy and its relevance for the taxonomic survey of Selaginella subg. Gymnogynum (Selaginellaceae)

The current circumscription of Selaginella subg. Gymnogynum fails to accurately define and describe the stem articulations and stem vascular system of its representatives. A structural revision may improve species delimitation within subgenus Gymnogynum and is thus pivotal for taxonomic and evolutionary studies in Selaginella. We analyzed 34 specimens from 12 species of S. subg. Gymnogynum, two species of S. subg. Exaltatae and one species of S. subg. Stachygynandrum, which we obtained from herbaria. Samples were subjected to the herborization reversal procedure and processed following usual methods in light microscopy. All sampled Gymnogynum species as well as S. exaltata are articulated. Only S. anaclasta (subg. Exaltatae) and S. coarctata (subg. Stachygynandrum) lack articulations. The articulation region can be characterized and classified based on the occurrence of swellings or nodules (hyperplasia), the predominant presence of pectin in the cell wall and formation of grooves that reach the cortical region (constrictions). These three traits combined form five articulation types. We found the following types of stem vascular system: haplostele, actinostele, plectostele and actino-plectostele. In Gymnogynum, we found the bistelic haplostele, plectostele and two variations of actinostele. Our analysis allowed for a standardized and revised characterization of species in subg. Gymnogynum, with additional information on subgenera Exaltatae and Stachygynandrum, thereby expanding the database of anatomical traits that may contribute not only to achieving a more accurate taxon delimitation but also to subsidizing further studies on the evolutionary history of Selaginella.

Ascorbic acid, sucrose and olive oil lipids mitigate the inhibitory effects of pectin on the bioaccessibility and Caco-2 cellular uptake of ferulic acid and naringenin.

Whole fruit and vegetable consumption is universally promoted as healthy, to a large extent due to their high contents of phytochemicals, including phenolics and dietary fibre. The major fibre in fruits and vegetables, pectin, however also decreases the bioavailability of phenolics and carotenoids. While ascorbic acid, sucrose and olive oil lipids may increase the bioavailability of various phenolics, their effects in the presence of pectin have not been investigated. This study aimed to evaluate the modulating effects of sucrose (5.0%), ascorbic acid (0.1%) and olive oil (2.5%) on the inhibition by pectin (2.0%) of ferulic acid and naringenin bioaccessibility and Caco-2 cellular uptake. Pectin reduced the bioaccessbility of ferulic acid and naringenin, by 45 and 65%, respectively. Sucrose mitigated the inhibitory effect of pectin and increased naringenin bioaccessbility from 7.9 to 15.0%. When added to digestions with ferulic acid and pectin, sucrose and olive oil totally negated pectin's bioaccessibility inhibition. The Caco-2 cellular uptake of bioaccessible ferulic acid was high (58.3%) and pectin and ascorbic acid together increased it to 85.6%. The Caco-2 cellular uptake of bioaccessible naringenin was also high (47.0%) and pectin increased it to 95.0%. Sucrose and olive oil for ferulic acid and only sucrose for naringenin totally negated the inhibitory effect of pectin on the overall in vitro availability (cellular uptake as percentage of amount of phenolic initially digested). The ameliorating effects of sucrose and olive oil are due to substantially increased bioaccessibility of the phenolics, probably due reduced encapsulation of the phenolics in pectin.

Effect of Rheological Properties of Sodium Alginate-pectin Composite Solution on the Formation and Texture of Core-shell Capsules

Based on the synergistic gel formation mechanism between sodium alginate and pectin in presence of calcium ion,the sodium alginate-pectin hydrogel beads with shell-core structure,i.e. core-shell capsule,were prepared using reverse spherification technique,by adding the calcium-containing core solution into the sodium alginate-pectin complex solution. The rheological properties of both sodium alginate-pectin complex and the core solution were tested with the texture analyzer and rheometer and their effects on the texture properties of the core-shell capsules were studied. Results indicated that the viscosity of the complex solution gradually decreased gradually with the increase of the proportion of pectin in the complex system. The sodium alginate and pectin hydrogel beads prepared with sodium alginate-pectin ratio of 7:3 (w/w)and the concentration was 0.6%,showed the highest value of maximum force((430.1±24.4) g·cm-2)and chewability of the outer shell((1054.9±23.4) g).The optimized spherification(standard rate was 100%)and texture properties(the highest value of maximum force was(376.3±18.2) g·cm-2 the chewability was(1104.0±43.3) g)were obtained with xanthan gum concentration of 0.4% and the calcium lactate concentration of 1.5% in core liquid.

Effect of Pectin Biodegradation with Aspergillus niger on Total Flavonoid Content of Citrus limon L.)

Lemon peel and leaf as well as lower grade of lemon contain a considerable amount of flavonoid which can be extracted to produce a valuable product. The presence of pectin in lemon hinders the extraction of flavonoid compound. This research was conducted to examine the effect of pectin biodegradation of lemon leaf, peel, and lower grade fruit using solid-state fermentation towards the yield of pectin, crude flavonoid, and total flavonoid content. Fermentation was carried out with the help of Aspergillus niger at 30℃ for 3, 5, 7, and 9 days of cultivation time. Pectin was extracted from the fermentation broth using citric acid. Crude flavonoid was extracted using maceration and stirred about 500 rpm at 50℃ for 40 minutes. Total flavonoid content was analyzed using a spectrophotometer. The optimum cultivation time of Aspergillus niger with leaf and peel was 9 days with a pectin yield from lemon leaf was 0.43% dry weight and the pectin yield from lemon peel was 0.04% dry weight. As for the lower grade fruit, a cultivation time for 7 days showed an optimal result with a pectin yield of 0.08% dry weight. The total flavonoid content in the leaf increased up to 94.3% (1.06 mg of the quercetin equivalents per g of substrate) whereas the total flavonoid content in the peel and lower grade fruit increased up to 42% (0.12 mg of the quercetin equivalents per g of substrate) and 48% (0.021 mg of the quercetin equivalents per g of substrate), respectively. These results highlighted the potential valorization of Citrus limon L. as an alternative source for producing flavonoid in food and pharmaceutical industry.

Co-encapsulation of α-tocopherol and resveratrol in oil-in-water emulsion stabilized by sodium caseinate: Impact of polysaccharide on the stability and bioaccessibility

Naturally self-assembling property of sodium caseinate (SC) provides the possibility of loading bioactive compounds to the oil-water interface of oil-in-water (O/W) emulsions. In this study, α-tocopherol (TOC) and resveratrol (RES) were encapsulated in the inner oil phase and the oil-water interface of SC-stabilized emulsions, respectively. Addition of polysaccharides increased the size and absolute value of ζ-potential of SC emulsions and surface coverage of oil droplets, improving the encapsulation of RES at the oil-water interface and storage stability of both TOC and RES. The effects were more pronounced in the presence of pectin (PEC) than gum Arabic (GA). Moreover, the digestive stability of TOC in SC emulsions was only improved by 0.5% and 1.0% PEC. Addition of 0.1–1.0% GA and 0.1% PEC promoted the bioaccessibility of TOC (~40%) and RES (~90%). These results should be useful for the co-encapsulation of bioactive components with different solubility based on protein-stabilized single emulsions.

Alkaline conditions better extract anti-inflammatory polysaccharides from winemaking by-products.

Winemaking generates large amounts of by-products, a well recognized source of phenolic compounds. However, less attention has been paid to the polysaccharide-rich fraction (PRF) and effects of fractionation techniques on its potential bioactivity. Therefore, PRFs from Syrah and Tempranillo winemaking by-products were extracted under aqueous (neutral pH conditions), acidic and alkaline conditions. PRFs were screened for their monosaccharide composition, uronic acid content, homogeneity and molecular weight. Anti-inflammatory activity of PRFs were evaluated on stimulated RAW 264.7 macrophages. PRF obtained in water and/or under acidic conditions showed heterogeneous profiles. As like as in the others, a heterogeneous and complex profile was detected in extracts procured under alkaline conditions. A high content of uronic acid was found in aqueous extracts, thus indicating the presence of pectin. Pectin and hemicellulose were present in PRFs procured under acidic conditions. Alkaline conditions rendered extracts containing a complex mixture of monosaccharides, mainly xylose. This latter PRF was the only one exhibiting anti-inflammatory potential (at 100 μg/mL) by reducing the release of TNF-α and activation of NF-κB in LPS-activated RAW 264.7 macrophages, with no effect on cell viability. Regardless of the grape variety, PRFs obtained under alkaline conditions were the best option to obtain bioactive polysaccharides with potential application as a source of anti-inflammatory compounds. A complex mixture of polymers may be responsible for the anti-inflammatory effects. Finally, according to results procured by NMR, it is possible to suggest that bioactive fractions are composed of a chain of α-L-Araf-(1 → 3) linked, β-D-Xylp- (1 → 4), α-D-Glcp-(1 → 4) linked, α-D-GalpA-(1 → 4), α-D-Gal-(1 → 2) forming possible RG I and RG II and xylan chains.

Effect of Pectin on the Expression of Proteins Associated with Mitochondrial Biogenesis and Cell Senescence in HT29-Human Colorectal Adenocarcinoma Cells.

Mitochondria dynamic is regulated by different proteins, maintaining a balance between fission and fusion. An imbalance towards mitochondrial fission has been associated with tumor cell proliferation. The aim of this study was to analyze whether pectin modifies the viability of human colon cancer cells and the expression of proteins involved in mitochondrial fusion and fission. The human colon carcinoma cell line HT29 cells was growth in 10% fetal bovine serum in the absence and presence of pectin. Pectin reduced HT29 cell viability in a concentration-dependent manner, reaching a plateau at 150~300 μmol/L pectin. The presence of 200 μmol/L pectin reduced the expression of dynamin-related protein-1 and increased expression of the mitochondrial fusion-associated proteins mitofusin-1 and 2. Expression of cyclin B1, a protein involved in G2/M transition, was found decreased in pectin-incubated HT29 cells. Moreover, expression of p53 protein, the amount of p53 in the nucleous and β-galactosidase activity, which are all biomarkers for cellular senescence, were significantly higher in pectin-incubated HT29 cells than in HT29 cells incubated without pectin. Expression of the protein B-cell lymphoma 2 (Bcl-2) homologous antagonist/killer was increased in response to incubation with pectin. However, incubation with pectin did not affect expression of Bcl-2-associated X protein or Bcl-2, or the caspase-3 activity. Overall, we concluded that pectin reduces the viability of human HT29 colon cancer cells, which is accompanied with a shift in the expression of proteins associated with mitochondrial dynamics towards mitochondrial fusion. Moreover, incubation with pectin favors cellular senescence over apoptosis in HT29 cells.

Structural variation among leaves in Aechmea distichantha Lem. (Bromeliaceae) rosettes, considering apical and basal differences

In tank-dependent bromeliads, leaves may exhibit anatomical and functional differences along the apical and basal regions, or according to the different positions in the rosette. Thus, the apical region of the leaf may invest in photosynthetic tissues, while the basal one invests in structures for water and nutrient storage. We suppose here, that differences among the tissue functions are strongly related to anatomical traits, especially the degree of methyl-esterification of pectins in the cell walls, at different positions along the rosette. Thus, the aims of this study were to quantify anatomical variations and describe the pectin composition of the cell wall, along the Aechmea distichantha Lem. rosette, to assess how the different tissues varied. We found that the water storage tissue showed higher variation between the apex and the base of the leaves than the other tissues, with higher expansion between the fourth leaf in development and the outer leaf in the rosette. Moreover, its cells were intensely labeled for epitopes of high methyl-esterified HGs, recognize by JIM7 antibody. The presence of pectin with high methyl-esterified groups in water storage tissue provides greater cell wall elasticity. The chlorenchyma showed the lowest Relative Distance Plasticity Index values, and its development in A. distichantha seems to occur early, in a very young leaf and inside the rosette tank.

Construction, stability, and enhanced antioxidant activity of pectin-decorated selenium nanoparticles.

Selenium nanoparticles (SeNPs) as a new replacement source of other Se forms applied in nutritional supplements have been associated with health-related issues. Pectin (PEC) as a well-known food-grade polysaccharide has been considered as a potential soft template for the preparation and stabilization of SeNPs in aqueous medium. In this study, therefore, PEC was used as a stabilizer and dispersing agent to form well-dispersed and stable SeNPs under a simple redox system of selenite and ascorbic acid. Se/PEC ratios significantly affected the color of the suspension, particle size, and surface morphology of the as-prepared SeNPs in the presence of PEC. PEC-SeNPs with a Se/PEC ratio of 1:2 appeared amorphous and exhibited a well-dispersed and stable spherical structure with an average size of ∼41 nm, which corresponds to the strong hydrogen bonding between the hydroxyl groups of PEC and SeNPs. The PEC-SeNPs (Se/PEC = 1:2) remained highly stable in different acidic solutions for at least 1 month. Small and highly stable PEC-SeNPs (Se/PEC = 1:2) possessed the strongest DPPH radical scavenging ability and antioxidant capacity among the evaluated PEC-SeNPs. They also possessed a low cytotoxic activity against cancer cells (SPCA-1 and HeLa) and normal cells (RWPE-1) in vitro. These findings suggested that pectin as a surface decorator could be effectively used to improve the stability and antioxidant capacity of SeNPs remarkably.

Research of biodegradation and antimicrobial properties of polyvinyl chloride sheetings with pectin and starch additives

The paper describes a new methodof stability assessment of polymericmaterials to destruction caused by various factors (such as mechanical loads, moisture and microorganisms' vital activity). This method includes puncture resistance comparison of researched material samples, determined after nine-day incubation of these samples in liquid nutrient medium with test microorganisms and daily 40 vol.% substitution of this medium for a sterile one, as well as after incubation of similar samples in a sterile medium, and without incubation of these samples. The described methodwas used to study stability of a number of new polymericmaterials to various types of destruction. The materials were made on the basis of vinyl chloride polymer with addition of 0, 1, 5 and 10 mass.% of starch and pectin. The effect of the mentioned materials on the growth and metabolicactivity in liquid nutrientmedium ofEscherichia coliATCC 25922 was studied also (according to dynamics of intensity change of elastic optical dispersion and conductivity of the mentioned medium during the first ten hours of its incubationat the presence of tested objects and test microorganisms). As a result, it is shown that all researched materials are resistant to moisture action. At the same time, allused additives even in 1 mass.% quantity considerably reduced mechanical strength of researched materials compared with pure vinyl chloride polymer; as well as increased biodegradationof thesematerials(though in substantially smaller degree at small quantities of the additives). Moreover,the lattereffect was provided by the addition of starchto vinyl chloride polymerin considerably greater degree, than the addition of pectin.Besides, all used additives reduced the antimicrobialeffect of the polyvinyl chloride base of researched materials. The more starch or pectin was contained in researched material, the greater reduction occurred; at the identical quantity of them it occurred in the presence of starch to a greater extent, than in the presence of pectin.

Interactions between four common plant-derived phenolic acids and pectin, and its effect on antioxidant capacity

Phenolic acids (PAs) are molecules of vegetable origin with high antioxidant capacity (AOXC) attributed to their hydroxyl groups. Vegetable cells store PAs within vacuoles, and when disrupted through mastication or food processing, PAs can interact with other molecules like fibers, which alters their AOXC. Mango (Mangifera indica L.) cv Ataulfo contains PAs and fiber, particularly pectin. Previous reports indicate that PAs interact between themselves and affect each other’s AOXC. The present work analyzed the interactions between the main PAs from mango cv Ataulfo and pectin, and how pectin affects their AOXC. We used UV–Vis spectrophotometry, fluorescence spectrophotometry and AOXC assays to study how pectin influences gallic, protocatechuic, chlorogenic and vanillic acid, individually, and in combinations of two, three and four PAs. Results showed that gallic acid was the most affected by the presence of pectin, which was related to its number and position of hydroxyl groups. The effect of pectin was not as obvious when three or four PAs were combined, suggesting that PAs preferentially interact among themselves, likely through hydrogen bonds. Pectin exerted mostly synergistic effects on AOXC values when added to one, two and four combined PAs; antagonistic effects were recorded when pectin was added to three combined PAs. The effect of pectin on AOXC was more noticeable when analyzed by the ORAC assay, and less when analyzed by the DPPH assay. Basic knowledge of the interactions between PAs and pectin is of great importance, since they are normally consumed alongside each other.

Fluorescent pseudomonads pursue media-dependent strategies to inhibit growth of pathogenic Verticillium fungi.

Verticillium species represent economically important phytopathogenic fungi with bacteria as natural rhizosphere antagonists. Growth inhibition patterns of Verticillium in different media were compared to saprophytic Aspergillus strains and were significantly more pronounced in various co-cultivations with different Pseudomonas strains. The Brassica napus rhizosphere bacterium Pseudomonas fluorescens DSM8569 is able to inhibit growth of rapeseed (Verticillium longisporum) or tomato (Verticillium dahliae) pathogens without the potential for phenazine or 2,4-diacetylphloroglucinol (DAPG) mycotoxin biosynthesis. Bacterial inhibition of Verticillium growth remained even after the removal of pseudomonads from co-cultures. Fungal growth response in the presence of the bacterium is independent of the fungal control genes of secondary metabolism LAE1 and CSN5. The phenazine producer P. fluorescens 2-79 (P_phen) inhibits Verticillium growth especially on high glucose solid agar surfaces. Additional phenazine-independent mechanisms in the same strain are able to reduce fungal surface growth in the presence of pectin and amino acids. The DAPG-producing Pseudomonas protegens CHA0 (P_DAPG), which can also produce hydrogen cyanide or pyoluteorin, has an additional inhibitory potential on fungal growth, which is independent of these antifungal compounds, but which requires the bacterial GacA/GacS control system. This translational two-component system is present in many Gram-negative bacteria and coordinates the production of multiple secondary metabolites. Our data suggest that pseudomonads pursue different media-dependent strategies that inhibit fungal growth. Metabolites such as phenazines are able to completely inhibit fungal surface growth in the presence of glucose, whereas GacA/GacS controlled inhibitors provide the same fungal growth effect on pectin/amino acid agar.

Microencapsulation of Anthocyanins from Grape Skins by Whey Protein Isolates and Different Polymers

Binding of anthocyanin extract from grapes (Fetească neagră variety) by whey protein isolate was first estimated through fluorescence spectroscopy quenching experiments. The data were analyzed using the modified Stern-Volmer equation, allowing the estimation of binding and thermodynamic parameters. The increase of binding constants, accessible fractions, and number of binding sites was highlighted when increasing the temperature, suggesting the presence of the dynamic quenching process. The HPLC analysis allowed the identification of anthocyanin composition of extract and powders, highlighting the presence of the malvidin-3-glucoside as the main anthocyanin. Molecular docking tests provided strong evidence on the involvement of α-lactalbumin and β-lactoglobulin in the tight binding of malvidin-3-glucoside. Further, grape anthocyanins were encapsulated within whey protein isolate and two different polysaccharides (acacia gum and pectin) by coacervation, followed by freeze-drying. The encapsulating efficiency varied between 94 and 99%. Two size smaller particles were obtained in case of microencapsulation in the presence of pectin when compared with acacia gum, as revealed by laser confocal scanning microscopy investigations. Significantly, the experimental variant with pectin allowed the entrapment of a higher amount of flavonoids. The antioxidant activities of the two experimental variants were comparable. The thermal stability experiments evidenced a relatively higher protective effect on anthocyanin degradation in the variant with pectin.

Aquatic adaptation of a laterally acquired pectin degradation pathway in marine gammaproteobacteria.

Mobile genomic islands distribute functional traits between microbes and habitats, yet it remains unclear how their proteins adapt to new environments. Here we used a comparative phylogenomic and proteomic approach to show that the marine bacterium Pseudoalteromonas haloplanktis ANT/505 acquired a genomic island with a functional pathway for pectin catabolism. Bioinformatics and biochemical experiments revealed that this pathway encodes a series of carbohydrate-active enzymes including two multi-modular pectate lyases, PelA and PelB. PelA is a large enzyme with a polysaccharide lyase family 1 (PL1)domain and a carbohydrate esterase family 8 domain, and PelB contains a PL1 domain and two carbohydrate-binding domains of family 13. Comparative phylogenomic analyses indicate that the pathway was most likely acquired from terrestrial microbes, yet we observed multi-modular orthologues only in marine bacteria. Proteomic experiments showed that P. haloplanktis ANT/505 secretes both pectate lyases into the environment in the presence of pectin. These multi-modular enzymes may therefore represent a marine innovation that enhances physical interaction with pectins to reduce loss of substrate and enzymes by diffusion. Our results revealed that marine bacteria can catabolize pectin, and highlight enzyme fusion as a potential adaptation that may facilitate microbial consumption of polymeric substrates in aquatic environments.

Characterization of Potential Polysaccharide Utilization Systems in the Marine Bacteroidetes Gramella Flava JLT2011 Using a Multi-Omics Approach.

Members of phylum Bacteroidetes are distributed across diverse marine niches and Flavobacteria is often the predominant bacterial class decomposing algae-derived polysaccharides. Here, we report the complete genome of Gramella flava JLT2011 (Flavobacteria) isolated from surface water of the southeastern Pacific. A remarkable genomic feature is that the number of glycoside hydrolase (GH) genes in the genome of G. flava JLT2011 is more than 2-fold higher than that of other Gramella species. The functional profiles of the GHs suggest extensive variation in Gramella species. Growth experiments revealed that G. flava JLT2011 has the ability to utilize a wide range of polysaccharides for growth such as xylan and homogalacturonan in pectin. Nearly half of all GH genes were located on the multi-gene polysaccharide utilization loci (PUL) or PUL-like systems in G. flava JLT2011. This species was also found to harbor the two xylan PULs and a pectin PUL, respectively. Gene expression data indicated that more GHs and sugar-specific outer-membrane susC-susD systems were found in the presence of xylan than in the presence of pectin, suggesting a different strategy for heteropolymeric xylan and homoglacturonan utilization. Multi-omics data (transcriptomics, proteomics, and metabolomics) indicated that xylan PULs and pectin PUL are respectively involved in the catabolism of their corresponding polysaccharides. This work presents a comparison of polysaccharide decomposition within a genus and expands current knowledge on the diversity and function of PULs in marine Bacteroidetes, thereby deepening our understanding of their ecological role in polysaccharide remineralization in the marine system.

Binding Studies of Pectin in Presence of Divalent Cations

Binding Studies of Pectin in Presence of Divalent Cations