Molecular Hydrophobicity Research Articles

Construction and digestive characterization of emulsions stabilized with octenyl succinic anhydride-modified curdlan.

To expand the scope of application of the insoluble polysaccharide curdlan (CUR), this study modified CUR with octenyl succinic anhydride (OSA) and evaluated the performance of the emulsion formed from the modified CUR derivative. Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction analysis showed that properties such as the molecular structure, crystallinity, and hydrophobicity of the OSA-modified CUR (COSA) changed significantly compared with those of the original CUR, indicating that the hydroxyl group of CUR was successfully replaced by OSA. Subsequently, a stable oil-in-water emulsion system of COSA loaded with curcumin was established. The stability of the emulsions was evaluated by analyzing their microstructure, rheological properties, and curcumin retention. The digestion characteristics of the emulsions were evaluated by in vitro simulated digestion experiments, and the COSA emulsion had higher stability and was better able to improve the chemical stability of curcumin compared to CUR. The OSA grafting resulted in emulsions with higher curcumin release rates and antioxidant capacities. These results indicate that COSA has the potential to be used as an encapsulating material for lipophilic nutrient emulsions and provides theoretical support for expanding the applications of chemically modified CUR derivatives.

Molecular Hydrophobicity Signature in Charged Bidimensional Clay Materials.

The unraveling of the hydrophobicity/hydrophilicity molecular signature of nanometric bidimensional confined systems represents a challenging task with repercussions in environmental transport processes. Swelling clay minerals represent an ideal model system, as hydrophobicity can be modified during material synthesis by substituting hydroxyls by fluorine in the structure, without additional surface treatment. This following work presents a combined approach, integrating experimental inelastic neutron scattering spectroscopy and ab initio molecular dynamics simulations, with the objective of advancing our understanding of the role of surface hydroxylation/fluorination and the extent of confinement on water properties. From computed structures, the analysis of molecular hydrophobicity/hydrophilicity signature was investigated in detail through water-cation-surface interactions. The results elucidate the influence of fluorination on interlayer species, thereby tracing the impact of the surface on the diminished number of water molecules in such a sample. It is notable that the strong cation-water interaction can overcome the disruptive influence of fluorine, thereby maintaining comparable water hydration shells around cations and resulting in an almost identical bidimensional confinement geometry for both hydroxylated and fluorinated specimens. The analysis of the hydrogen-bond network revealed a significant reorganization of the water molecules due to fluorination. Our results suggest that a quantitative molecular signature of hydrophobicity/hydrophilicity can be derived from the analysis of the formation of cavities in the confined fluid. This new finding represents a robust approach for generalizing the hydrophobicity/hydrophilicity character for a wide variety of bidimensional systems while proposing a framework for the design of new materials with controlled water properties.

Unveiling spatiotemporal distribution, partitioning, and transport mechanisms of tire additives and their transformation products in a highly urbanized estuarine region

Numerous tire additives are high-production volume chemicals that are used extensively worldwide. However, their presence and partitioning behavior remain largely unknown, particularly in marine environments. This study is the first to reveal the spatiotemporal distribution, multimedia partitioning, and transport processing of 22 tire additives and their transformation products (TATPs) in a highly urbanized estuary (n = 166). Nineteen, 18, and 20 TATPs were detectable in water, suspended particulate matter (SPM), and sediments, respectively, with total levels of 59.7–2021 ng/L, 164–6935 ng/g, and 4.66–58.4 ng/g, respectively. The multimedia partitioning mechanisms of TATPs are governed by their molecular weight, hydrophobicity, and biodegradation rate. Mass inventories coupled with model simulations have revealed that substantial quantities of TATPs accumulate within estuarine environments, and these compounds can be continuously transported into the ocean, particularly during the wet season. According to the multi-criteria evaluation approach, four and three TATPs were identified as high-priority pollutants during the dry and wet seasons, respectively. Unexpectedly, N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine quinone was only listed as a medium-priority pollutant. This study underscores the importance of marine surveillance and advocates for particular attention to these ubiquitous but underexplored TATPs in future studies.

An Analysis of Combined Molecular Weight and Hydrophobicity Similarity between the Amino Acid Sequences of Spike Protein Receptor Binding Domains of Betacoronaviruses and Functionally Similar Sequences from Other Virus Families

Recently, we proposed a new method, based on protein profiles derived from physicochemical dynamic time warping (PCDTW), to functionally/structurally classify coronavirus spike protein receptor binding domains (RBD). Our method, as used herein, uses waveforms derived from two physicochemical properties of amino acids (molecular weight and hydrophobicity (MWHP)) and is designed to reach into the twilight zone of homology, and therefore, has the potential to reveal structural/functional relationships and potentially homologous relationships over greater evolutionary time spans than standard primary sequence alignment-based techniques. One potential application of our method is inferring deep evolutionary relationships such as those between the RBD of the spike protein of betacoronaviruses and functionally similar proteins found in other families of viruses, a task that is extremely difficult, if not impossible, using standard multiple alignment-based techniques. Here, we applied PCDTW to compare members of four divergent families of viruses to betacoronaviruses in terms of MWHP physicochemical similarity of their RBDs. We hypothesized that some members of the families Arteriviridae, Astroviridae, Reoviridae (both from the genera rotavirus and orthoreovirus considered separately), and Toroviridae would show greater physicochemical similarity to betacoronaviruses in protein regions similar to the RBD of the betacoronavirus spike protein than they do to other members of their respective taxonomic groups. This was confirmed to varying degrees in each of our analyses. Three arteriviruses (the glycoprotein-2 sequences) clustered more closely with ACE2-binding betacoronaviruses than to other arteriviruses, and a clade of 33 toroviruses was found embedded within a clade of non-ACE2-binding betacoronaviruses, indicating potentially shared structure/function of RBDs between betacoronaviruses and members of other virus clades.

Machine Learning-Based Toxicological Modeling for Screening Environmental Obesogens.

The emerging presence of environmental obesogens, chemicals that disrupt energy balance and contribute to adipogenesis and obesity, has become a major public health challenge. Molecular initiating events (MIEs) describe biological outcomes resulting from chemical interactions with biomolecules. Machine learning models based on MIEs can predict complex toxic end points due to chemical exposure and improve the interpretability of models. In this study, a system was constructed that integrated six MIEs associated with adipogenesis and obesity. This system showed high accuracy in external validation, with an area under the receiver operating characteristic curve of 0.78. Molecular hydrophobicity (SlogP_VSA) and direct electrostatic interactions (PEOE_VSA) were identified as the two most critical molecular descriptors representing the obesogenic potential of chemicals. This system was further used to predict the obesogenic effects of chemicals on the candidate list of substances of very high concern (SVHCs). Results from 3T3-L1 adipogenesis assays verified that the system correctly predicted obesogenic or nonobesogenic effects of 10 of the 12 SVHCs tested, and identified four novel potential obesogens, including 2-benzotriazol-2-yl-4,6-ditert-butylphenol (UV-320), 4-(1,1,5-trimethylhexyl)phenol (p262-NP), 2-[4-(1,1,3,3-tetramethylbutyl)phenoxy]ethanol (OP1EO) and endosulfan. These validation data suggest that the screening system has good performance in adipogenic prediction.

Vinyl Ether Maleic Acid Polymers: Tunable Polymers for Self-Assembled Lipid Nanodiscs and Environments for Membrane Proteins.

Native lipid bilayer mimetics, including those that use amphiphilic polymers, are important for the effective study of membrane-bound peptides and proteins. Copolymers of vinyl ether monomers and maleic anhydride were developed with controlled molecular weights and hydrophobicity through reversible addition-fragmentation chain-transfer polymerization. After polymerization, the maleic anhydride units can be hydrolyzed, giving dicarboxylates. The vinyl ether and maleic anhydride copolymerized in a close to alternating manner, giving essentially alternating hydrophilic maleic acid units and hydrophobic vinyl ether units along the backbone after hydrolysis. The vinyl ether monomers and maleic acid polymers self-assembled with lipids, giving vinyl ether maleic acid lipid particles (VEMALPs) with tunable sizes controlled by either the vinyl ether hydrophobicity or the polymer molecular weight. These VEMALPs were able to support membrane-bound proteins and peptides, creating a new class of lipid bilayer mimetics.

Seaweeds and Their Secondary Metabolites: A Promising Drug Candidate With Novel Mechanisms Against Cancers and Tumor Angiogenesis.

Cancer continually remains a severe threat to public health and requires constant demand for novel therapeutic drug candidates. Due to their multi-target orientation, lesser toxicity, and easy availability, natural compounds attract more attention from current scientific research interest than synthetic drug molecules. The plants and microorganisms produce a huge variety of secondary metabolites because of their physiological diversification, and the seaweeds occupy a prominent position as effective drug resources. Seaweeds comprise microscopic or macroscopic photosynthetic, multicellular, eukaryotic marine algae that commonly inhabit the coastal regions. Several molecules (such as polysaccharides, lipids, proteinaceous fractions, phenolic compounds, and alkaloids) are derived from seaweeds, and those small molecules are well attractive and more effective in cancer research programs. Their structural variation, derivative diversity, and quantity vary with seaweed species and geographical origin. Their smaller molecular weight, unique derivatives, hydrophobicity, and degree of sulfation are reported to be causes of their crucial role against different cancer cells in vitro. Several reports showed that those compounds selectively discriminate between normal and cancer cells based on receptor variations, enzyme deficiency, and structural properties. The present review aimed to give a concise explanation regarding their structural diversity, extractability, and mechanism of action related to their anti-cancer activities based on recently published data.

Comprehensive characterization and expression profiling of BBX gene family in soybean in response to UV-B stress

The BBX gene family encodes transcription factors that regulate several biological processes, such as plant growth, development, and stress response. They have been identified and thoroughly studied in numerous plant species. The functional role of the BBX gene family against UV-B stress in soybean has not been well documented. Herein, this study focused on a comprehensive investigation of the GmBBX genes in soybean and their expression patterns in response to UV-B exposure. A total of 184 BBX genes were identified and analyzed to determine the conserved domain. Single and double B-box and CCT domains were found across these proteins, indicating potential functional diversity. The protein physicochemical properties showcased diverse characteristics, highlighting molecular size, stability, and hydrophobicity. Phylogenetic analysis revealed five distinct clades, showcasing a non-uniform distribution of GmBBX genes. Chromosomal mapping showed a non-uniform distribution of GmBBX genes across the 20 chromosomes of soybean. The highest number of genes (26) were found on chromosome 13, whereas chromosomes 5 and 15 displayed the lowest number of genes (3 genes each). Gene structure analysis revealed variations in exon-intron patterns, while motif composition analysis unveiled conserved motifs among GmBBX proteins. Gene duplication indicated that the expansion of the GmBBX genes was linked with tandem and dispersed duplications. Gene ontology analysis revealed enrichment of terms associated with light stimulus, response to abiotic stress, and molecular functions such as zinc ion binding. The promoter region reveals cis-acting elements related to hormones, light, and stress responses. The GmBBX genes exhibited differential expression in response to UV-B stress, suggesting their possible role in plant defense against UV-B stress. This study will provide a solid foundation for further analysis of the molecular mechanisms of GmBBX genes in soybean against UV-B stress.

Bioaccumulation of legacy and emerging per- and polyfluoroalkyl substances in hydroponic lettuce and risk assessment for human exposure

Reclaimed water for irrigation or hydroponic cultivation provides exposure pathways for per- and polyfluoroalkyl substances (PFAS) to enter the human food chain. This study employed hydroponic methods to investigate the behavior of legacy PFAS and emerging chlorinated polyfluoroalkyl ether sulfonic acids (Cl-PFESAs) in lettuce grown under environment-related exposure levels and assessed the human exposure risks from consuming contaminated lettuce. Overall, PFAS in lettuce were concentration-dependent, with long-chain PFAS tending to accumulate in roots and short-chain PFAS accumulating more in shoots. The enrichment of PFAS in lettuce was jointly influenced by their chain length and polar functional groups. Specifically, the root concentration factors (RCFs) of PFAS generally increased with increasing chain length, and RCF values of most perfluoroalkanesulfonic acids (PFSAs) were significantly higher than those of perfluoroalkyl carboxylic acids (PFCAs) with the same chain length (p < 0.01), while the translocation factors (TFs) exhibited opposite trends. RCF values of perfluorooctane sulfonate (PFOS) and its alternatives, Cl-PFESAs, were ranked as follows: 8:2 Cl-PFESA (mean: 139) > 6:2 Cl-PFESA (28.6) > PFOS (25.7), which was attributed to the increased molecular size and hydrophobicity resulting from the insertion of ether bonds and additional CF2 in 8:2 Cl-PFESA. Notably, TF value of 8:2 Cl-PFESA (mean: 0.007) was the smallest among all PFAS, indicating 8:2 Cl-PFESA was difficult to transfer to nutritional compartments. Adults and children would exceed the most conservative health-based reference dose (RfD) by consuming approximately 15.9–148 g and 7.92–74.0 g of contaminated lettuce per day, implying high health risks.

Effects of molecule hydrophobicity and structural flexibility of appended bispecific antibody on Protein A chromatography

Appended bispecific antibody (aBsAb) with two single chain variable fragments (scFv) linked at the c-terminus of its heavy chains is one of the promising formats in bispecific therapeutics. The presence of hydrophobic and flexible scFv fragments render aBsAb molecules higher molecule hydrophobicity and structural flexibility compared to monoclonal antibody (mAb), thus making its purification more challenging. We set out to investigate how the unique molecular properties of aBsAb affect its performance on Protein A chromatography. We showed that aBsAb has a high propensity for chromatography-induced aggregation due to its high molecule hydrophobicity, and this couldn't be improved by the addition of common chaotropic salts. Moreover, the presence of chaotropic salts, such as arginine hydrochloride (Arg-HCl), retarded aBsAb elution during Protein A chromatography rather than facilitating which was widely observed in mAb Protein A elution. Nevertheless, we were able to overcome the aggregation issue by optimizing elution condition and improved aBsAb purity from 29 % to 93 % in Protein A eluate with a high molecular weight (HMW) species of less than 5 %. We also showed that the high molecular flexibility of aBsAb leads to different hydrodynamic sizes of the aBsAb molecule post Protein A elution, neutralization, and re-acidification, which are pH dependent. This is different from mAbs where their sizes do not change post neutralization even with re-exposure to acid. The above unique observations of aBsAb in Protein A chromatography were clearly explained from the perspectives of its high molecular hydrophobicity and structural flexibility.

Effect of glycation with three polysaccharides on the structural and emulsifying properties of ovalbumin

Herein, three types of ovalbumin (OA)-polysaccharide conjugates were prepared with three polysaccharides (XG: xanthan gum; GG: guar gum; KGM: konjac glucomannan) for the fish oil emulsion stabilization. The glycation did not change the spectra bands and secondary structure percentages of OA, whereas it decreased the molecular surface hydrophobicity of OA. The initial emulsion droplet sizes were dependent on the polysaccharide types, OA preparation concentrations, polysaccharide: OA mass ratios, and glycation pH. The emulsion stability was mainly dependent on the polysaccharide types, polysaccharide: OA mass ratios, and glycation pH. However, it was minorly dependent on the OA preparation concentrations. The emulsions stabilized by conjugates with high polysaccharide: OA mass ratios (e.g., ≥3:5 for OA-GG) or appropriate glycation pH (e.g., 5.0–6.1 for OA-XG) showed no obvious creaming during the room temperature storage. This work provided basic knowledge on the structural modification and functional application of a protein.

Two-phase system model to predict hydrophobic organic compound partition to heterogeneous soil dissolved organic matter across China

Soil dissolved organic matter (SDOM) is an important part of the DOM pool in terrestrial systems, influencing the transport and fate of many pollutants. In this study, SDOMs from different regions across China were compared by a series of spectroscopic methods, including UV–vis spectroscopy, fluorescence spectroscopy, and Fourier transform infrared (FTIR) spectroscopy, and the hydrophobicity was quantified by partition coefficients of SDOM in the aqueous two-phase system (KATPS). The molecular weight, aromaticity, and hydrophobicity of SDOM from different regions exhibited strong heterogeneity, KATPS combined with UV–vis and fluorescence indices can be readily used for differentiating heterogeneous SDOM, and SDOMs were compositionally and structurally different from DOMs in aquatic systems based on spectral characterization. Importantly, the two-phase system (TPS) model has only been validated by DOMs in freshwater systems, and good organic carbon‒water partition coefficient (KOC) predictive power (RMSE = 0.11) could be provided by the TPS model when applied to heterogeneous SDOM without calibration, showing its broad applicability. Our results demonstrate the applicability of the TPS model for predicting the sorption behavior of terrestrial DOM, broadening the application scope of the TPS model and indicating its potential as a routine model for the risk assessment of hydrophobic organic compounds (HOCs) in organic contaminated sites.

Digestion of whey peptide induces antioxidant and anti-inflammatory bioactivity on glial cells: Sequences identification and structural activity analysis

Whey derived peptides have shown potential activity improving brain function in pathological condition. However, there is little information about their mechanism of action on glial cells, which have important immune functions in brain. Astrocytes and microglia are essential in inflammatory and oxidative defense that take place in neurodegenerative disease. In this work we evaluate antioxidant and anti-inflammatory potential bioactivity of whey peptide in glial cells. Peptides were formed during simulated gastrointestinal digestion (Infogest protocol), and low molecular weight (<5kDA) peptides (WPHf) attenuated reactive oxygen species (ROS) production induced by hydrogen peroxide stimulus in both cells in dose-dependent manner. WPHf induced an increase in the antioxidant glutathione (GSH) content and prevented GSH reduction induced by lipopolysaccharides (LPS) stimulus in astrocytes cells in a cell specific form. An increase in cytokine mRNA expression (TNFα and IL6) and nitric oxide secretion induced by LPS was attenuated by WPHf pre-treatment in both cells. The inflammatory pathway was dependent on NFκB activation. Bioactive peptide ranking analysis showed positive correlation with hydrophobicity and negative correlation with high molecular weights. The sequence identification revealed 19 peptides cross-referred with bioactive database. Whey peptides were rich in leucine, valine and tyrosine in the C-terminal region and lysine in the N-terminal region. The anti-inflammatory and antioxidant potential of whey peptides were assessed in glia cells and its mechanisms of action were related, such as modulation of antioxidant enzymes and anti-inflammatory pathways. Features of the peptide structure, such as molecular size, hydrophobicity and types of amino acids present in the terminal region are associated to bioactivity.

Unraveling the impacts of fermentation methods on the protein structural, foaming and air-water interfacial properties of buckwheat steamed bread dough liquor

Liquid lamella has crucial impacts on stabilizing gas cells and buckwheat steamed bread (BSB) quality due to the high fiber content and lack of gluten protein in buckwheat. The liquid lamella was collected by ultracentrifugation as the dough liquor (DL). This study explored the composition, foaming and interfacial properties of DL from lactic acid bacteria (LAB), yeast, LAB and yeast cooperate (LAB-yeast), and chemical acidified and yeast (CA-yeast) fermented buckwheat dough, as well as the unfermented buckwheat dough. Compared with the unfermented dough, the DL yield of LAB-yeast, yeast, and CA-yeast fermented dough decreased by 4.09%, 3.93%, and 7.67%, respectively. The protein molecular weight and surface hydrophobicity of DL were dramatically reduced by LAB, LAB-yeast, and CA-yeast fermentation as compared to unfermented DL. Among all DL samples, the unfermented and yeast DL showed the highest protein surface hydrophobicity and surface activity, resulting in the greatest foam stability. The protein in CA-yeast DL displayed the fastest interface diffusion because its DL had the highest amount of low molecular weight protein, the lowest viscosity and protein content. Compared with the unfermented dough, the LAB and LAB-yeast fermentation decreased, while the CA-yeast fermentation increased the strain hardening index (SHI) of the dough. This enhanced strain hardening behavior contributed to a decrease in the average cell area and an increase in cell density, making the crumb structure of CA-yeast fermented BSB homogeneous and dense.

Design, synthesis, and antiviral activity of 1-aryl-4-arylmethylpiperazine derivatives as Zika virus inhibitors with broad antiviral spectrum

Zika virus (ZIKV) disease has been given attention due to the risk of congenital microcephaly and neurodevelopmental disorders after ZIKV infection in pregnancy, but no vaccine or antiviral drug is available. Based on a previously reported ZIKV inhibitor ZK22, a series of novel 1-aryl-4-arylmethylpiperazine derivatives was designed, synthesized, and investigated for antiviral activity by quantify cellular ZIKV RNA amount using RT-qPCR method in ZIKV-infected human venous endothelial cells (HUVECs) assay. Structure-activity relationship (SAR) analysis demonstrated that anti-ZIKV activity of 1-aryl-4-arylmethylpiperazine derivatives is not correlated with molecular hydrophobicity, multiple new derivatives with pyridine group to replace the benzonitrile moiety of ZK22 showed stronger antiviral activity, higher ligand lipophilicity efficiency as well as lower cytotoxicity. Two active compounds 13 and 33 were further identified as novel ZIKV entry inhibitors with the potential of oral available. Moreover, both ZK22 and newly active derivatives also possess of obvious inhibition on the viral replication of coronavirus and influenza A virus at low micromolar level. In summary, this work provided better candidates of ZIKV inhibitor for preclinical study and revealed the promise of 1-aryl-4-arylmethylpiperazine chemotype in the development of broad-spectrum antiviral agents.

Unraveling the characteristics of dissolved organic matter removed by aluminum species based on FT-ICR MS analysis

Given the complexity of dissolved organic matter (DOM) and its interactions with coagulant chemicals, the mechanisms of DOM removal by aluminum (Al) coagulants remains a significant unknown. In this study, six test waters containing DOM with molecular weight (MW, <1 kDa, 1–10 kDa and >10 kDa) and hydrophobicity (hydrophilic, transphilic and hydrophobic) were prepared and coagulated with Al0, Al13 and Al30. The molecular-level characteristics of DOM molecules that were removed or resistant to removal by Al species were analyzed using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). The results showed that at the molecular level, saturated and reduced tannins and lignin-like compounds containing abundant carboxyl groups exhibited higher coagulation efficiency. Unsaturated and oxidized lipids, protein-like, and carbohydrates compounds were relatively resistant to Al coagulation due to their higher polarity and lower content of carboxyl groups. Al13 removed molecules across a wider range of molecular weights than Al0 and Al30, thus the DOC removal efficiency of Al13 was the highest. This study furthers the understanding of interactions between Al species and DOM, and provides scientific insights on the operation of water treatment plants to improve control of DOM.

LFQRatio: A Normalization Method to Decipher Quantitative Proteome Changes in Microbial Coculture Systems.

The value of synthetic microbial communities in biotechnology is gaining traction due to their ability to undertake more complex metabolic tasks than monocultures. However, a thorough understanding of strain interactions, productivity, and stability is often required to optimize growth and scale up cultivation. Quantitative proteomics can provide valuable insights into how microbial strains adapt to changing conditions in biomanufacturing. However, current workflows and methodologies are not suitable for simple artificial coculture systems where strain ratios are dynamic. Here, we established a workflow for coculture proteomics using an exemplar system containing two members, Azotobacter vinelandii and Synechococcus elongatus. Factors affecting the quantitative accuracy of coculture proteomics were investigated, including peptide physicochemical characteristics such as molecular weight, isoelectric point, hydrophobicity, and dynamic range as well as factors relating to protein identification such as varying proteome size and shared peptides between species. Different quantification methods based on spectral counts and intensity were evaluated at the protein and cell level. We propose a new normalization method, named "LFQRatio", to reflect the relative contributions of two distinct cell types emerging from cell ratio changes during cocultivation. LFQRatio can be applied to real coculture proteomics experiments, providing accurate insights into quantitative proteome changes in each strain.

Process optimization and identification of antioxidant peptides from enzymatic hydrolysate of bovine bone extract, a potential source in cultured meat

Bone protein is a significant secondary product of the meat industry, comprising a substantial quantity of protein. These proteins could be broken down through enzymatic hydrolysis to generate antioxidant peptides. This study aimed to produce antioxidant peptides from bovine bone extract by enzymatic hydrolysis utilizing Flavourzyme and Protamex by optimizing enzyme amounts and time using the Box–Behnken design. The final optimized conditions obtained through the model were as follows: The amount of Flavourzyme was 1,100 U, the amount of Protamex was 2,814 U, and the time was 3.77 (h). Bovine bone extract hydrolysate (BBEH) was purified stepwise using ultrafiltration membranes with molecular cutoffs of 5, 3, and 1 kDa. To assess the antioxidant capacity of the fractions, several methods were used, including radical scavenging activity “1,1-diphenyl-2-picrylhydrazyl (DPPH),” “2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS),” metal chelating activity (MCA), reducing power (RP), and thiobarbituric acid assay (TBA). The results indicated that the ultrafiltration fraction with a molecular weight of less than 1 kDa showed significant antioxidant activity, with 48, 42, and 50% inhibition rates for DPPH, ABTS, and metal chelating, respectively. Using size exclusion chromatography, the fraction with a molecular weight less than 1 kDa was further separated into five sub-fractions: Frac-I, Frac-II, Frac-III, Frac-IV, and Frac-V. Sub-Frac-III, which exhibits significant DPPH radical scavenging activity (55%) and a reducing power of 0.8 at 700 nm, was separated into six sub-sub-fractions using reversed-phase HPLC (RP-HPLC) based on molecular weight and hydrophobicity. The sub-sub-fraction with the highest value for DPPH radical scavenging activity was sub-Fra-III-6, which exhibited approximately 69.45% activity. The sub-Fra-III-6 was analyzed using LC–MS/MS, which identified two specific peptides: Ala-Pro-Phe with a mass of 333.12 Da and Asp-His-Val with a mass of 369.14 Da. These two peptides are likely the primary peptides that might have a crucial role in antioxidant capacity. It can be concluded that BBEH is a valuable source of natural antioxidants and has the potential to serve as a viable resource in the cultured meat industry.

A comparison of typical ultrafiltration processes in drinking water treatment: Implications for fouling control and disinfection performance

Despite the rapid proliferation of ultrafiltration (UF) membranes in drinking water treatment, the long-term operational performance of various hybrid UF processes remains inadequately understood. Herein, three typically applied hybrid UF processes were directly compared on a pilot scale, focusing on effluent quality, fouling control and subsequent disinfection performance. Water quality analysis revealed that the direct UF process exhibited significant removal of high molecular weight and hydrophobicity fractions, while the integration of UF with conventional water treatment processes further enhanced the removal of medium molecular weight and transition fractions, as well as fluorescent organic matter. The augmentation of pretreatment processes resulted in the hybrid UF process featuring enhanced anti-fouling properties, characterized by decreased reversible and irreversible resistances under the constant flux condition. This improvement was attributed to reduced interaction between the membrane and foulants. Furthermore, the subsequent disinfection performance of hybrid UF processes was evaluated using chlorine and chlorine dioxide as disinfectants. The chlorine decay rate and disinfection by-product formation indicated that chlorine dioxide was more suitable for the UF process, whereas chlorine was better for the hybrid UF process with low organic matter content in the effluent. These comprehensive comparisons offer valuable insights for making informed decisions in adopting suitable hybrid UF processes for practical water treatment applications.

Insights into coagulation, softening and ozonation pre-treatments for reverse osmosis membrane fouling control in reclamation of textile secondary effluent

Pre-treatment was an effective strategy to mitigate membrane fouling, while controversial fouling control performance and mechanism still restricted its application. Herein, coagulation, softening and ozonation pre-treatments were applied to mitigate reverse osmosis (RO) fouling in reclamation of textile secondary effluent. The results showed coagulation pre-treatment negligibly alleviated membrane fouling by dosing FeCl3 coagulant due to the low coagulation efficiency and dissolved organic carbon (DOC) removal (only 11 %) toward effluent organic matter (EfOM) with low molecular weight (2300–6145 Da). Unexpectedly, pre-ozonation caused more severe RO fouling with the increasing ozone doses owing to the enhanced bridging action of divalent cations between membrane and ozonated EfOM; however, the opposite phenomenon was observed when divalent cations were removed by softening due to the preferential removal of biopolymers, the decrease in molecular weight and hydrophobicity of EfOM. Especially, at ozone dose of 1.0 mg O3/mg DOC, flux loss and irreversible fouling resistance enhanced by 8.60 % and 25.4 %, but markedly reduced by 24.0 % and 41.2 % in the absence of divalent cations, respectively. Extended DLVO (XDLVO) theory further unveiled the different roles of pre-treatments in RO fouling control was mainly due to the variation of adhesion interfaces between RO membrane and foulants, especially for the Lewis acid-base (AB) interaction energy. We proposed that softening + ozonation pre-treatment was effective to control RO fouling. More importantly, the reclaimed water satisfy the national standard of China (GB/T 19923–2005) for industrial water reuse after softening + ozonation + RO membrane treatment, which is promising to reclaim textile wastewater.