High Molecular Weight Compounds Research Articles

Microbial communities associated with kelp detritus in temperate and subantarctic intertidal sediments.

Kelp forests, among the most productive ecosystems on Earth, cover large areas of the South Atlantic coast. Sediment heterotrophic bacteria have a pivotal role in the degradation of kelp biomass, however, the response of sediment microbial communities to periodic kelp biomass inputs is mostly unknown. Here, we show that kelp biomass induced rapid changes in overlying water chemistry and shifts in sediment microbial communities, which differed in the experimental systems containing Macrocystis pyrifera (M) and Undaria pinnatifida (U) with sediments of the respective regions. We observed results compatible with the degradation of labile, high molecular weight compounds into smaller and more refractory compounds towards the end of the incubations. The capability of microbial communities to degrade alginate, the major component of kelp cell walls, significantly increased with respect to controls after kelp biomass addition (Absorbance at 235 nm 1.2 ± 0.3 and 1.0 ± 0.2 for M and U, respectively, controls <0.2, t = 4 days). Shifts in microbial community structure (based on 16S rRNA gene amplicon sequencing) were tightly related to the kelp treatment and, to a lesser extent, to the sediment provenance (Principal Coordinates Analysis, 80 % of variation explained in the first two axes). Dissolved oxygen, pH, salinity, alginolytic potential, Absorbance at 235 and 600 nm, total N, total C, and SUVA index correlated significantly with community structure. Differentially abundant populations between kelp-amended treatments and controls included members of the Flavobacteriia class (Algibacter and Polaribacter), and Gammaproteobacteria (Psychromonas and Marinomonas), among others. Metagenomes of M and U-amended sediments contained sequences from 18 of the 19 enzyme families related to alginate or fucoidan degradation. Specific taxonomic groups were associated with enzyme classes targeting different substrates, suggesting niche differentiation. This work expands our knowledge on the patterns of microbial assemblages from intertidal sediments in response to kelp biomass inputs.

Exploration of changes in the chemical composition of sedimentary organic matter and the underlying processes during biodegradation through advanced analytical techniques

Environmental context Organic matter (OM) biodegradation plays a key role as it is one of the main processes causing changes in the amount, composition and properties of OM in sediment. However, a complete understanding of its processes and mechanisms is still not reached. In this study, we aim to explore the chemical composition changes during biodegradation and identify underlying processes. Rationale Although the scientific community has widely investigated organic matter biodegradation processes, only a limited number of studies have explored the molecular changes of this material, whereas its structure, composition and origin play a key role in these processes. Methodology We decided to examine the effects of biodegradation on the chemical composition of sedimentary organic matter and to explore the underlying mechanisms. We conceived a laboratory-based degradation experiment utilising organic-rich sediments artificially composed of two contrasting organic matter end-members (i.e. soil and algae) under two oxygen conditions. The sediment samples before and after incubation were then analysed by laser desorption ionisation–Fourier-transform–ion cyclotron resonance–mass spectrometry for molecular characterisation and by thermally assisted hydrolysis and methylation gas chromatography–mass spectrometry in order to offer insights into the mechanisms driving the biodegradation processes. Results Our results from molecular characterisation unveiled distinct pathways of biodegradation contingent upon the source material. Moreover, they hinted at a predilection for altering high molecular weight compounds like lignin &amp; carboxylic-rich alicyclic molecules (CRAM) and condensed aromatic structures (CAS), manifesting as a conversion into lower molecular weight counterparts. Furthermore, the complementary findings from biomarker analyses underscored the influence of environmental factors – specifically oxygen conditions and microbial communities – on organic matter decomposition. Discussion Although this study is a controlled laboratory experiment and more studies are needed, it demonstrates the intricate interplay among chemical, biological and environmental factors that profoundly shape the reactivity of organic matter. This study underscores the critical need for persistent inquiry, aimed at unravelling the factors and conditions governing the diverse pathways of biodegradation.

Besinlerde melanoidinlerin oluşumu ve sağlık üzerine etkileri

Melanoidins are brown, high molecular weight compounds generated in the late stages of the Maillard reaction from reducing sugars and proteins or amino acids during thermal food processing. The primary source of melanoidin is bread and bakery products in the diet. Although the chemical structures of melanoidins are not precisely known, the daily dietary intake is estimated at approximately 10 g. Melanoidins exist as monosaccharides (coffee, beer, and cocoa) and melanoproteins (bread and bakery products), depending on the food composition they form. The formation of melanoidins in foods depends on conditions such as composition of products, heat treatment time and temperature, pH, water and activity of reactants. Melanoidins have many beneficial effects on health, such as prebiotic, antioxidant, antimicrobial, anticarcinogenic, antihypertensive, xenobiotic enzyme activity, appetite regulation, and energy intake. In the gastrointestinal tract, melanoidins behave as dietary fibre by promoting the growth of bifidobacteria. In addition, melanoidins can preserve the quality of food by contributing to the texture and flavour of food. This review examines the formation, amount of food, mechanism of action and effects on human health of melanoidins.

Buccal Permeation of Polysaccharide High Molecular Weight Compounds: Effect of Chemical Permeation Enhancers.

The greatest achievement in the advanced drug delivery field should be the optimization of non-invasive formulations for the delivery of high molecular weight compounds. Peptides, proteins, and other macromolecules can have poor membrane permeation, principally due to their large molecular weight. The aim of this work was to explore the possibility of administering fluorescently labeled dextrans (molecular weight 4-150 kDa) across the buccal mucosa. Permeation experiments across pig esophageal mucosa were carried out using fatty acids and bile salts as penetration enhancers. The data obtained show that it is possible to increase or promote the mucosa permeation of high molecular weight dextrans by using caprylic acid or sodium taurocholate as the chemical enhancers. With these enhancers, dextrans with molecular weight of 70 and 150 kDa, that in passive conditions did not permeate, could cross the mucosa in detectable amounts. FD-70 and FD-150 showed comparable permeability values, despite the molecular weight difference. The results obtained in the present work suggest that the buccal administration of high molecular weight compounds is feasible.

Molecular-level evidence of early lipid transformations throughout oceanic depths

Our understanding of lipid biogeochemistry of the ocean’s interior is still in its infancy. Here we focus on early lipid transformation and the formation of lipid degradation products in the NE Atlantic Ocean (49.0°N, 16.5°W). We employed high resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), a method that allows observation and elemental composition assignment of thousands of lipids in a single sample. Using these data, we infer molecular-level changes that occur during lipid transformation in the oceanic water column to shed new light on early lipid transformation processes and the formation of lipid decomposition intermediates, here termed CHO compounds (i.e., lipid-derived species that contain carbon, hydrogen and oxygen in their molecular formula). We considered the distribution of molecular rings and/or double bonds (DBE), H/C and O/C ratios, molecular diversity based on the number of mass spectral signals for monoisotopic species, and carbon number in CHO molecules. Data are elaborated for the four ocean zones, the epipelagic, mesopelagic, bathypelagic and abyssal. The highest molecular diversity characterizes CHO compounds associated with the epipelagic zone, which is explained by numerous and diverse planktonic communities inhabiting the epipelagic and by the effects of both biotic and abiotic processes on lipid transformation. Lipid transformations include crosslinking (condensation), partial degradation or fragmentation, double bond reduction, oxidation, hydrogenation, dehydrogenation and cyclization. Crosslinking likely results in a unimodal distribution of carbon number of CHO compounds, in contrast to cell lipids (referred to as Reported lipids based on the Lipid Maps Database), which have a bimodal distribution of carbon number. CHO compounds that appear to be formed by fragmentation (decrease of the number of C atoms) and ring/double bond reduction were more stable to further transformation and remained longer in the water column, i.e., these compounds were transferred deeper into the water column. Low unsaturation and fast transport to depth promotes CHO compound preservation in the water column. Dehydrogenation leads to increased unsaturation (average DBE up to 21.3), condensation, and cyclization, resulting in high molecular weight compounds with a high degree of unsaturation. Our data demonstrate that lipids with cyclic structures are more refractory than those with acyclic structures. The formation of aromatic structures is not a significant process during early lipid transformation in the oceanic water column.

Transport properties of hydrophilic compounds in PLGA microspheres

Biodegradable polyesters, such as the poly(lactic-co-glycolic acid) (PLGA), have been extensively used as a polymer matrix for entrapping a variety of active compounds. In this study, the physicochemical phenomena that control the mass transport mechanism of hydrophilic compounds released from PLGA microspheres were identified. This study aims to produce and characterize PLGA microspheres loaded with metformin hydrochloride (MH) and perform a case study using the literature data of PLGA microspheres loaded with fluorescein isothiocyanate-dextran (FITC-dextran). The MH is a low molecular weight compound that was easily and rapidly transported by diffusion mechanism through the microsphere pores. The FITC-dextran, as a high molecular weight compound, depended on the mechanism of polymer erosion and mesopore formation, with 18 days of duration, before its release by diffusion mass transfer. Values of the effective diffusion coefficient of MH and FITC-dextran, both in PLGA, were 2.4 x 10-13 and 5.3 x 10-18 m2 s-1, respectively, with a difference of five orders of magnitude attributed to the molecular weight of these hydrophilic compounds and the main mass transport that governed their release. This study provides important insights into the mechanisms of mass transfer and their correlation with the physicochemical properties of both hydrophilic compounds and the PLGA matrix, contributing to the development of biodegradable controlled delivery systems for a variety of applications in chemical, biotechnological, and pharmaceutical industries.

Identification Of Bioactive Phytochemicals By GC-MS Profiling, Phytochemical Screening, And TLC Using Methanolic Extract Of Carissa Carandas Linn Leaf

Background Carissa carandas (Apocynaceae) is a thorny evergreen shrub known as Karonda. It has small berry-shaped fruits, used as an additive in many pickles or spices in northern India. Objective The objective was to identify the phytochemical constituents, gas chromatography-mass spectrometry (GC-MS), and TLC screening by using a methanolic extract from the leaves of Carissa carandas. Methods and materials Leaves of C. carandas were collected, shade dried, pulverized, and extracted successively with methanol by the Soxhlet technique. The crude extracts were later exposed to phytochemical screening for secondary metabolites, thin-layer chromatography, and GC-MS analysis. Result The phytochemical screening revealed the presence of alkaloids, saponin, tannin, flavonoid, phenol, steroid, carbohydrate, glycosides, and terpenoids. TLC analysis was performed, and the Rf value was calculated. The GC-MS analysis determined the presence of 6 main phytochemical compounds in the methanolic extract of Carissa carandas leaf, showing that there were different types of high and low molecular weight compounds. Conclusion The results of the present study pave the invention of herbal medicines for several ailments by using the Carissa carandas plant, which may lead to the development of novel drugs.

Root Exudation of Specialized Molecules for Plant-Environment Interaction

It has been estimated that between 40 and 60 % of the assimilated carbon is diverted to the roots and released in the rhizosphere in form of root exudates. Root exudates thus define a complex mixture of low and high molecular weight compounds, including carbohydrates, amino acids, organic, and proteins, but also a broad spectrum of specialized molecules, such as flavonoids, glucosinolates, terpenoids, or alkaloids. Root exudates favour soil mineral nutrition, can bind to soil aggregate and in turn modify soil physico-chemical properties, but also mediate plant-plant, plant-microbe, and plant-animal interactions belowground. With this review, we aim to highlight how chemical ecologists have approached the study of root exudates-mediated interactions between plants and their biotic and abiotic surroundings. We do so by presenting a series of study cases for, on one hand, showcasing different methodologies that have been developed to test the activity of different root exudates, and, on the other hand, to show the broad array of interactions mediated by root exudates. Ultimately, we aim to spur further research and collaborations between chemists and ecologists studying belowground chemically-mediated interactions, so as to tackle essential challenges in terms of food security and climate change in the near future.

Burkholderia vietnamiensis G4 as a biological agent in bioremediation processes of polycyclic aromatic hydrocarbons in sludge farms.

Polycyclic aromatic hydrocarbons (PAHs) are one of the main pollutants generated by the refining and use of oil. To search bioremediation alternatives for these compounds, mainly in situ, considering the biotic and abiotic variables that affect the contaminated sites is determinant for the success of bioremediation techniques. In this study, bioremediation strategies were evaluated in situ, including biostimulation and bioaugmentation for 16 priority PAHs present in activated sludge farms. B. vietnamiensis G4 was used as a biodegradation agent for bioaugmentation tests. The analyses occurred for 12months, and temperature and humidity were measured to verify the effects of these factors on the biodegradation. We used the technique GC-MS to evaluate and quantify the degradation of PAHs over the time of the experiment. Of the four treatments applied, bioaugmentation with quarterly application proved to be the best strategy, showing the degradation of compounds of high (34.4% annual average) and low (21.9% annual average) molecular weight. A high degradation rate for high molecular weight compounds demonstrates that this technique can be successfully applied in bioremediation of areas with compounds considered toxic and stable in nature, contributing to the mitigation of impacts generated by PAHs.

Characterization of size-resolved emissions of alkylated and nitrated polycyclic aromatic hydrocarbons (PAHs) from various combustion scenarios

In this study, we examined the size-resolved emissions of alkylated and nitrated polycyclic aromatic hydrocarbons (alkyl- and nitro-PAHs) from various combustion sources including residential solid fuels, cigarette smoking, domestic waste burning, and vehicular exhausts, which have been scarcely addressed. The estimated emission factors (eEFs) of these PAH derivatives were generally highest from the biomass burning sources. Very few nitro-PAHs were detected in cigarette smoking, cooking, and vehicle emission sources. Significant linear or non-linear relationships were observed between methylated PAHs and their parent compounds; whereas the relationships were weak for most nitro-PAHs, revealing the difference and similarity in their emission or accumulation formation mechanisms. The size distributions of individual methylated phenanthrenes (PHEs) and PHE were very similar in each source, but different between the sources. Generally, in sources with higher eEFs, these compounds were more tendentious to associate with the fine fractions. The intra-source size distributions of the methylated naphthalenes (NAPs) and NAP were different in some sources. The cooking and vehicle sources showed the lowest distributions of these PAHs derivatives in fine particles. The size fractionations of nitro-PAHs among the sources were very variable due to the low emissions, except for a few high molecular weight compounds showing more robust enrichment in the fine fractions. In addition to the size-resolved characterization, this work also highlights the need for understanding their formation and fractionation mechanisms.

Synthesis of Radioiodinated Compounds. Classical Approaches and Achievements of Recent Years.

This review demonstrates the progress in the synthesis of radioiodinated compounds over the past decade. The possibilities and limitations of radiopharmaceuticals with different iodine isotopes, as well as the synthesis of low and high molecular weight compounds containing radioiodine, are discussed. An analysis of synthesis strategies, substrate frameworks, isolation methods, and metabolic stability, and the possibility of industrial production of radioiodinated organic derivatives which can find applications in the synthesis of drugs and diagnostics are presented.

Optimization of growth of Levilactobacillus brevis SP 48 and in vitro evaluation of the effect of viable cells and high molecular weight potential postbiotics on Helicobacter pylori.

Several Levilactobacillus brevis strains have the potential to be used as probiotics since they provide health benefits due to the interaction of live cells, and of their secreted products, with the host (tissues). Therefore, the development of simple fermentation processes that improve cell viability to reduce industrial production costs, and at the same time the characterization and biological evaluation of cell-free postbiotics that can further promote application, are of great interest. In the present study, small scale batch fermentations on semi defined media, deprived of animal derived raw materials, were used to optimize growth of L. brevis SP48, reaching 1.2 ± 0.4 × 1010CFU/ml of viable cells after 16h of growth. Displacement, competition, and inhibition assays compared the effect, on Helicobacter pylori, of L. brevis cells to that of its partially purified potentially postbiotic fraction rich in exopolysaccharides and proteins. The expression of pro and anti-inflammatory biochemical markers indicated that both samples activated antimicrobial defenses and innate immunity in a gastric model. Moreover, these compounds also acted as modulators of the inflammatory response in a gut in vitro model. These data demonstrate that the high molecular weight compounds secreted by L. brevis SP48 can contrast H. pylori and reduce inflammation related to intestinal bowel disease, potentially overcoming issues related to the preservation of probiotic viability.

Comprehensive assessment of dissolved organic matter processing in the Amazon River and its major tributaries revealed by positive and negative electrospray mass spectrometry and NMR spectroscopy

Rivers are natural biogeochemical systems shaping the fates of dissolved organic matter (DOM) from leaving soils to reaching the oceans. This study focuses on Amazon basin DOM processing employing negative and positive electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI[±] FT-ICR MS) and nuclear magnetic resonance spectroscopy (NMR) to reveal effects of major processes on the compositional space and structural characteristics of black, white and clear water systems. These include non-conservative mixing at the confluences of (1) Solimões and the Negro River, (2) the Amazon River and the Madeira River, and (3) in-stream processing of Amazon River DOM between the Madeira River and the Tapajós River. The Negro River (black water) supplies more highly oxygenated and high molecular weight compounds, whereas the Solimões and Madeira Rivers (white water) contribute more CHNO and CHOS molecules to the Amazon River main stem. Aliphatic CHO and abundant CHNO compounds prevail in Tapajos River DOM (clear water), likely originating from primary production. Sorption onto particles and heterotrophic microbial degradation are probably the principal mechanisms for the observed changes in DOM composition in the Amazon River and its tributaries.

The dicing activity of DCL3 and DCL4 is negatively affected by flavonoids.

The dicing activities of DCL3 and DCL4 are inhibited by accumulated metabolites in soybean leaves. Epicatechin and 7,4'-dihydroxyflavone inhibited Arabidopsis DCL3 and DCL4 in vitro. Flavonoids are major secondary metabolites in plants, and soybean (Glycine max L.) is a representative plant that accumulates flavonoids, including isoflavonoids, to high levels. Naturally-occurring RNA interference (RNAi) against the chalcone synthase (CHS) gene represses flavonoid (anthocyanin) biosynthesis in an organ-specific manner, resulting in a colorless (yellow) seed coat in many soybean cultivars. To better understand seed coat-specific naturally-occurring RNAi in soybean, we characterized soybean Dicer-like (DCL) 3 and 4, which play critical roles in RNAi. Using a previously established dicing assay, two dicing activities producing 24- and 21-nt siRNAs, corresponding to DCL3 and DCL4, respectively, were detected in soybean. Dicing activity was detected in colorless seed coats where RNAi against CHS genes was found, but no dicing activity was detected in leaves where CHS expression was prevalent. Biochemical analysis revealed that soybean leaves contained two types of inhibitors effective for Arabidopsis Dicers (AtDCL3 and AtDCL4), one of which was a heat-labile high molecular weight compound of 50 to 100 kD while another was a low molecular weight substance. We found that some flavonoids, such as epicatechin and 7,4'-dihydroxyflavone, inhibited both AtDCL3 and AtDCL4, but AtDCL4 was more sensitive to these flavonoids than AtDCL3. These results suggest that flavonoids inhibit the dicing activity of DCL4 and thereby attenuate RNAi in soybean leaves.

Recovery of Antioxidants from Tomato Seed Industrial Wastes by Microwave-Assisted and Ultrasound-Assisted Extraction.

Tomato seed (TS) wastes are obtained in large amounts from the tomato processing industry. In this work, microwave-assisted extraction (MAE) and ultrasound-assisted extraction (UAE) of antioxidant compounds from TS were optimized by using response surface methodology. The effect of MAE and UAE main extraction parameters was studied on total phenolic content (TPC) and antioxidant activity (DPPH) responses. Antioxidant, structural, morphological, and thermal properties of MAE and UAE extracts were evaluated. A great influence of ethanol concentration was observed in both extraction methods. Optimal MAE conditions were determined as 15 min, 80 °C, 63% ethanol and 80 mL, with a desirability value of 0.914, whereas 15 min, 61% ethanol and 85% amplitude (desirability = 0.952) were found as optimal conditions for UAE. MAE extracts exhibited higher TPC and antioxidant activity values compared to UAE (1.72 ± 0.04 and 1.61 ± 0.03 mg GAE g TS−1 for MAE and UAE, respectively). Thermogravimetric analysis (TGA) results suggested the presence of some high molecular weight compounds in UAE extracts. Chlorogenic acid, rutin and naringenin were identified and quantified by HPLC-DAD-MS as the main polyphenols found by MAE and UAE, showing MAE extracts higher individual phenolics content (1.11–2.99 mg 100 g TS−1). MAE and UAE have shown as effective green techniques for extracting bioactive molecules with high antioxidant activity from TS with high potential to be scaled-up for valorizing of TS industrial wastes.

Modification of isoprene rubber with high molecular weight compounds in mixtures

Modification of isoprene rubber with high molecular weight compounds in mixtures

Influence of the conservation mode of seawater for dissolved organic carbon analysis

Marine dissolved organic matter (DOM) is one of the largest exchangeable organic carbon reservoir on the planet. The main proxy to track the distribution of DOM in the aquatic environments remains dissolved organic carbon (DOC). Thereby the optimal protocol for long-term DOC preservation in seawater samples must be defined. In this context, we monitored bulk DOC concentrations and its size class distribution in filtered seawater samples during yearlong experiments. With different conservation mode, we tested two types of commonly used materials (borosilicate brown glass and high-density polyethylene, HDPE) and three conditioning protocols (untreated, acidified at pH 2 and frozen at −20 °C). Offshore samples collected along the entire water column of the Pacific Ocean and stored in HDPE bottles were also analysed after 2 years of storage at pH of 2 and compared to frozen samples. Results demonstrated that bulk DOC concentrations can be accurately determined in untreated samples for one month and for years in frozen samples as well as in acidified samples, when samples are stored in acid cleaned HDPE bottles or flame sealed glass ampoules. Storage in brown glass vials with Bakelite caps seems more uncertain. The study of the size class distribution of DOC reveals the possibility to study DOM for 1 month in filtered samples with no additional treatment and for years in frozen samples when stored in acid cleaned HDPE bottles. Significant changes in DOC size fractionation were observed when samples were acidified. The high molecular weight (HMW) compounds and the humic substances from the upper 1000 m were significantly degraded at pH 2, incorporating DOC in the low molecular weight (LMW) fractions. These experiments provide preservation guidelines for future studies that aim either to study bulk DOC or the chemical properties marine DOM. It is recommended to store seawater in HDPE vials at −20 °C for DOM study, or at pH 2 for bulk DOC measurements.

Populus alba cationic cell-wall-bound peroxidase (CWPO-C) regulates the plant growth and affects auxin concentration in Arabidopsis thaliana

The poplar cationic cell-wall-bound peroxidase (CWPO-C) mediates the oxidative polymerization of lignin precursors, especially sinapyl alcohols, and high molecular weight compounds that cannot be oxidized by other plant peroxidases, including horseradish peroxidase C. Therefore, CWPO-C is believed to be a lignification-specific peroxidase, but direct evidence of its function is lacking. Thus, the CWPO-C expression pattern in Arabidopsis thaliana (Arabidopsis) was determined using the β-glucuronidase gene as a reporter. Our data indicated that CWPO-C was expressed in young organs, including the meristem, leaf, root, flower, and young xylem in the upper part of the stem. Compared with the wild-type control, transgenic Arabidopsis plants overexpressing CWPO-C had shorter stems. Approximately 60% of the plants in the transgenic line with the highest CWPO-C content had curled stems. These results indicate that CWPO-C plays a role in cell elongation. When plants were placed horizontally, induced CWPO-C expression was detected in the curved part of the stem during the gravitropic response. The stem curvature associated with gravitropism is controlled by auxin localization. The time needed for Arabidopsis plants overexpressing CWPO-C placed horizontally to bend by 90° was almost double the time required for the similarly treated wild-type controls. Moreover, the auxin content was significantly lower in the CWPO-C-overexpressing plants than in the wild-type plants. These results strongly suggest that CWPO-C has pleiotropic effects on plant growth and indole-3-acetic acid (IAA) accumulation. These effects may be mediated by altered IAA concentration due to oxidation.

Effect of peroxydisulfate oxidation catalyzed with ordered mesoporous carbons on controlling ultrafiltration membrane fouling by algal organic matter.

As typical ordered mesoporous carbons (OMCs) materials, CMK-3 and CMK-8 were proposed for catalyzing peroxydisulfate (PDS), and the OMCs/PDS process was combined with membrane filtration to remove algal extracellular organic matter and mitigate membrane fouling. The CMK-3/PDS process achieved substantial reduction of dissolved organic carbon and UV254, followed by CMK-8/PDS. The degradation behavior of fluorescent organics demonstrated the superior performance of OMCs/PDS, while the decomposition of high molecular weight (MW) compounds and generation of lower MW organics were observed. Generally, CMK-3 possessed higher catalytic activity on PDS compared with CMK-8 and powdered activated carbon. The CMK-3/PDS process distinctly decreased the fouling resistances for polyether sulfone and polyvinylidene fluoride membranes, with the reversible resistance reduced by 59.5-83.2% and irreversible resistance declined by 71.7-73.0%. In the meanwhile, CMK-3/PDS prolonged the volumes to the transition period, and postponed the cake layer's generation. The characterization of the membrane morphologies and chemical compositions also showed effective alleviation of fouling. The generated SO4-, OH, O2- and 1O2 as major active oxidation species provided radical as well as non-radical reaction ways for pollutants removal. Overall, our study provides some new ideas for membrane-based combined water purification processes.

Membrane Technology for Valorization of Mango Peel Extracts

Mango peel is rich in nutritional and functional compounds, such as carbohydrates, dietary fibers, proteins, and phenolic compounds, with high potential to be applied in the food industry. Most of the investigation about recovery of bioactive compounds from fruit bioproducts involves extraction techniques and further separation of target compounds. There is still a lack of information about the potential of membrane processes to recover the nutritive/functional compounds present in aqueous extracts of those bioproducts. This research is addressed to study the performance of ultrafiltration (UF), followed by nanofiltration (NF) of UF permeates, to fractionate the compounds present in aqueous extracts of mango peel. Both UF and NF concentration processes were carried up to a volume concentration factor of 2.0. Membranes with molecular weight cut-offs of 25 kDa and 130 Da were used in the UF and NF steps, respectively. UF and NF concentrates showed antioxidant activity, attributed to the presence of phenolic compounds, with rejections of about 75% and 98.8%, respectively. UF membranes totally rejected the higher molecular weight compounds, and NF membranes almost totally concentrated the fermentable monosaccharides and disaccharides. Therefore, it is envisaged that NF concentrates can be utilized by the food industry or for bioenergy production.