Screening of key odorants and anthocyanin compounds of cv. Okuzgozu (Vitis vinifera L.) red wines with a free run and pressed pomace using GC-MS-Olfactometry and LC-MS-MS

The principal purpose of the present work is to characterize the aroma, aroma-active, and anthocyanin profiles of Okuzgozu wines and to observe the effect of the pomace pressing technique on these parameters. A total of 58 and 59 volatile compounds were identified and quantified in free-run juice wine (FRW) and pressed pomace wine (PW). Alcohols were found as the most dominant group among aroma compounds followed by esters and acids. However, among all these compounds, only 11 and 13 of them could be considered as key odorants in aromatic extracts of FRW and PW, respectively. According to GC-MS-O analysis, ethyl octanoate (fruity), phenyl ethyl acetate (fruity), and 2-phenyl ethanol (flowery) were found as the main contributors to the overall scent of both wines. Beyond the aroma profiles, anthocyanin contents of both types of wines were also investigated, and total 14 and 15 anthocyanins were identified and quantified in FRW and PW. Malvidin-3-glycoside and its acetyl and coumaroyl forms were identified as the dominant anthocyanins in both wines. It is worth noting the pressing application (2.0 atm) led to an increase of some unpleasant notes in the aroma providing chemical, pharmacy, and fermented aromas in wine. On the other hand, the wines produced with pressed pomace presented higher amounts of anthocyanins.

Review of the fate and transformation of per- and polyfluoroalkyl substances (PFASs) in landfills

A critical review of existing publications is presented i) to summarize the occurrence of various classes of per- and polyfluoroalkyl substances (PFASs) and their sources in landfills, ii) to identify temporal and geographical trends of PFASs in landfills; iii) to delineate the factors affecting PFASs in landfills; and iv) to identify research gaps and future research directions. Studies have shown that perfluoroalkyl acids (PFAAs) are routinely detected in landfill leachate, with short chain (C4-C7) PFAAs being most abundant, possibly indicating their greater mobility, and reflecting the industrial shift towards shorter-chain compounds. Despite its restricted use, perfluorooctanoic acid (PFOA) remains one of the most abundant PFAAs in landfill leachates. Recent studies have also documented the presence of PFAA-precursors (e.g., saturated and unsaturated fluorotelomer carboxylic acids) in landfill leachates at concentrations comparable to, or higher than, the most frequently detected PFAAs. Landfill ambient air also contains elevated concentrations of PFASs, primarily semi-volatile precursors (e.g., fluorotelomer alcohols) compared to upwind control sites, suggesting that landfills are potential sources of atmospheric PFASs. The fate of PFASs inside landfills is controlled by a combination of biological and abiotic processes, with biodegradation releasing most of the PFASs from landfilled waste to leachate. Biodegradation in simulated anaerobic reactors has been found to be closely related to the methanogenic phase. The methane-yielding stage also results in higher pH (>7) of leachates, correlated with higher mobility of PFAAs. Little information exists regarding PFAA-precursors in landfills. To avoid significant underestimation of the total PFAS released from landfills, PFAA-precursors and their degradation products should be determined in future studies. Owing to the semi-volatile nature of some precursor compounds and their degradation products, future studies also need to include landfill gas to clarify degradation pathways and the overall fate of PFASs.

Risk exposure assessment of per- and polyfluoroalkyl substances (PFASs) in drinking water and atmosphere in central eastern China

We examined per- and polyfluoroalkyl substances (PFASs) in air from eight cities, and in water from six drinking-water treatment plants (DWTPs), in central eastern China. We analyzed raw and treated water samples from the DWTPs for 17 ionic PFASs with high-performance liquid chromatography/negative-electrospray-ionization tandem mass spectrometry (HPLC/(-)ESI-MS/MS), and analyzed the gas and particle phases of atmospheric samples for 12 neutral PFASs by gas chromatography-mass spectrometry (GC-MS). Perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA) were the dominant compounds in drinking water, and fluorotelomer alcohols (FTOHs) dominated in atmospheric samples. Of all the compounds in the treated water samples, the concentration of PFOA, at 51.0 ng L^-1, was the highest. Conventional treatments such as coagulation (COA), flocculation (FOC), sedimentation (SED), and sand filtration (SAF) did not remove PFASs. Advanced treatments, however, including ultrafiltration (UF) and activated carbon (AC), removed the majority of PFASs except for shorter-chain PFASs such as perfluorobutanoic acid (PFBA) and perfluoropentanoic acid (PFPA). We also investigated human exposure to PFASs via drinking water and the atmosphere and found that the mean daily intake of PFASs was 0.43 ng kg^-1 day^-1.

Fate of perfluorooctanoic acid (PFOA) in sewage sludge during microwave-assisted persulfate oxidation treatment

The fate of perfluorooctanoic acid (PFOA) has been investigated for an emerging sludge treatment technique using microwave heating-assisted persulfate (PS) oxidation. The effect of heating temperature (20, 50, and 70 °C) and PS dose (PS1: 0.01; PS2: 0.1; PS3: 0.2 g/g wet sludge) was studied in sludge spiked with PFOA at an environmentally relevant concentration (200 ng/g wet weight). Control degradation experiments using spiked sludge without PS addition and background sludge (no PFOA spike) with PS addition were also conducted at each temperature. Sludge samples were analyzed for eight perfluorocarboxylic acids (PFCAs) (C4 - C11) using LC-MS/MS. At 20 °C (PS2 dose), minimal (~ 5%) removal of the spiked PFOA was observed after 72 h, suggesting the need for elevated treatment temperature. For the same PS dose (0.1 g /g sludge), treatment at 50 and 70 °C showed a decrease in PFOA concentration with increasing temperature, with ~ 28 and ~ 42% removal following 4 h of treatment. No significant increase in degradation was observed for the highest dose (PS3) after 2 h, possibly indicating self-scavenging of PS at high dosage. Due to the low initial spiking concentration of PFOA and low extraction recovery, all shorter-chain PFCAs (< C8), the degradation products of PFOA, were below quantification limits in all sludge samples.

GABA Detection with Nano-ITIES Pipet Electrode: A New Mechanism, Water/DCE-Octanoic Acid Interface

Interface between two immiscible electrolyte solutions (ITIES) supported on the orifice of a pipet have become a powerful platform to detect a broad range of analytes. We present here the detection of γ-aminobutyric acid (GABA) with the nanoITIES pipet electrodes for the first time. GABA has a net charge of zero in an aqueous solution at pH ≈ 7, and it has not previously been detected at ITIES. In this work, we demonstrated GABA detection at ITIES in an aqueous solution at pH ≈ 7, where we introduced a novel detection strategy based on "pH modulation from the oil phase". To the best of our knowledge, this is the first report of such. Current increases linearly with increasing concentrations of GABA, ranging from 0.25 mM to 1.0 mM. The measured half-wave transfer potential of GABA is -0.401 ± 0.010 V ( n = 22) vs E1/2,TBA. The measured diffusion coefficient for GABA detection at nanoITIES pipet electrode is 6.09 (±0.58) × 10-10 m2/s ( n = 5). Experimental results indicate that protons generated from octanoic acid dissociation in the oil phase do not come out from the oil phase into the aqueous phase; neither were protons produced in the aqueous phase. NanoITIES pipet electrodes with radii of 320-340 nm were used in the current study. This new strategy and knowledge presented here lays the groundwork for the future development of ITIES pipet electrodes, especially for the detection of electrochemically nonredox active analytes.

Distribution of perfluorinated compounds in drinking water treatment plant and reductive degradation by UV/SO32- process

Perfluorinated compounds (PFCs), which are widely used in industrial and residential areas, have a large negative impact on the environment. This study investigated the removal efficiency of five PFCs in a drinking water treatment plant. The results indicate that the total PFC concentration in raw water is 261.51 ng L^-1 and that perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are the predominant pollutants. Among all of the treatment processes, coagulation sedimentation process had the highest removal ratio of PFCs (36.12%), and removal ratio was the least in the sand filtration process. The ozonation/activated carbon and disinfection processes increased the concentration of PFCs. Therefore, developing an effective treatment to degrade PFCs is feasible. In this study, we proposed a method using UV irradiation of SO₃^2- at 365 nm to degrade PFCs. The SO₃^2- concentration, pH, and initial concentration had profound impacts on the degradation of PFCs. When the PFC initial concentration was 20 mg L^-1, the SO₃^2- concentration was 2.4 g L^-1, and in the presence of buffer, the degradation of PFCs was the most efficient, with the degradation ratio close to 100% after 60 min of reaction. During the degradation of PFCs, short-chain PFCs and hydrofluorinated carboxylic acid were generated. From the above, we proposed a detailed mechanism of degradation and its possible pathways.

Thermodynamics of aqueous perfluorooctanoic acid (PFOA) and 4,8-dioxa-3H-perfluorononanoic acid (DONA) from DFT calculations: Insights into degradation initiation

Modern fluorosurfactants introduced during and after perfluoroalkyl carboxylates/sulfonates phase-out present chemical features designed to facilitate abatement, hence reducing persistence. However, the implications of such features on environmental partitioning and stability are yet to be fully appreciated, partly due to experimental difficulties inherent to the handling of their (diluted) aqueous solutions. In this work, rigorous quantum chemistry calculations were carried out in order to provide theoretical insights into the thermodynamics of hydroperfluorosurfactants in aqueous medium. Estimates of acid dissociation constant (pK_a), standard reduction potential (E⁰), and bond dissociation enthalpy (BDE) and free energy (BDFE) were computed for perfluorooctanoic acid (PFOA), 4,8-dioxa-3H-perfluorononanoic acid (DONA) and their anionic forms via ensemble averaging at density functional theory level with implicit solvent models. A ‹pK_a› in the neighborhood of zero and a E⁰ of about 2.2 V were obtained for PFOA. Predictions for the acidic function of DONA compare well with PFOA's, with a pK_a of 0.8-1.5 and a E⁰ of 2.07-2.15 V. Deprotonation thus represents the dominant phenomenon at environmental conditions. Calculations indicate that H-abstraction of the aliphatic proton of DONA by a hydroxyl radical is the thermodynamically favored reaction path in oxidative media, whereas hydrolysis is not a realistic scenario due to the high dissociation constant. Short intramolecular interactions available to the peculiar hydrophobic tail of DONA were also reviewed, and the relevance of the full conformational space of the fluorinated side chain discussed.

Temperature-dependent Henry's Law constants of 4-alkyl branched-chain fatty acids and 3-methylindole in an oil-air matrix and analysis of volatiles in lamb fat using selected ion flow tube mass spectrometry

RATIONALE

4-Alkyl branched-chain fatty acids and 3-methylindole are characteristic flavor compounds associated with sheep meat. Determining their partitioning behavior between the gas and condensed phase and ultimately developing a correlation between the compound's headspace concentration and sensory descriptive grouping are important for high-throughput characterization and grading classification.

METHODS

The headspace concentrations of 3-methylindole, 4-methyloctanoic acid, 4-ethyl-octanoic acid, and 4-methylnonanoic acid above corn-oil-based standard solutions and lamb fat samples were measured using selected ion flow tube-mass spectrometry (SIFT-MS). The standard solutions were equilibrated at 80, 100, 110 and 125°C while the fat samples were equilibrated at 125°C. Statistical evaluation, linear and polynomial regression analyses were performed to establish the compound-specific and temperature-dependent Henry's Law constants, enthalpy (ΔH) and entropy (ΔS) of phase changes.

RESULTS

The Henry's Law constants (k_H^cp ) were calculated from the regression analysis with a high degree of confidence (p < 0.05) and linearity (r²  > 0.99). The k_H^cp increased with increase in equilibrium temperature. The empirical calculation of ΔH and ΔS at different temperatures confirmed the temperature-dependence of the Henry's Law constants. The headspace concentrations of the lamb-flavor compounds were determined above actual lamb fat samples and the corresponding condensed-phase concentrations were successfully derived.

CONCLUSIONS

The temperature-dependent Henry's Law constants, ΔH, and ΔS of phase changes for 3-methylindole, 4-methyloctanoic acid, 4-ethyloctanoic acid, and 4-methylnonanoic acid in an air-oil matrix were empirically derived. The effectiveness of SIFT-MS for the direct, real-time, and rapid determination of key flavor compounds in lamb fat samples was established.

Nitrogen dioxide radicals mediated mineralization of perfluorooctanoic acid in aqueous nitrate solution with UV irradiation

Effective decomposition of perfluorooctanoic acid (PFOA) has received increasing attention in recent years because of its global occurrence and resistance to most conventional treatment processes. In this study, the complete mineralization of PFOA was achieved by the UV-photolysis of nitrate aqueous solution (UV/Nitrate), where the in-situ generated nitrogen dioxide radicals (NO₂) efficiently mediated the degradation of PFOA. In particular, when the twinborn hydroxyl radicals were scavenged, the production of more NO₂ radicals realized the complete mineralization of PFOA. DFT calculations further confirm the feasibility of PFOA removal with NO₂. Near-stoichiometric equivalents of fluoride released rather than the related intermediates were detected in solution after decomposition of PEOA, further demonstrating the complete degradation of PFOA. Possible PFOA degradation pathways were proposed on the basis of experimental results. This work offers an efficient strategy for the complete mineralization of perfluorinated chemicals, and also sheds light on the indispensable roles of nitrogen dioxide radicals for environmental pollutants removal.

Thermal- and photo-induced degradation of perfluorinated carboxylic acids: Kinetics and mechanism

Perfluorinated carboxylic acids (PFCAs) of different carbon chain lengths are chemicals of concern to human health and their removal, using conventional remediation technologies, is challenging. The present paper pursuits thermal and photo-induced degradation of PFCAs (F(CF₂)_nCOOH, n = 1-9) under various concentrations of four different acids (HNO₃, H₂SO₄, HCl, and H₃PO₄) covering a range of strong acidic to basic pH. For thermal-induced experiments, the temperature was set at 40 °C, 60 °C, and 80 °C at acid strengths of 0.04-18.4 M. Photo-induced experiments were conducted at pH 0.5, 7.0, and 13.0 under a light intensity of (150 ± 10) × 100 μW/cm². The degradation first-order rate constant (k_1, h^-1) as a function of [H⁺] was modeled by considering equilibrium of nondissociated (F(CF₂)_nCOOH, HX) and dissociated (F(CF₂)_nCOO^-, X^-) species of PFCAs (HX ⇌ X^- + H⁺, pK_a = -0.1). Species-specific rate constants, k₁^HX, reasonably described the trend of thermal and photo decay of PFCAs, where k₁^HX increased with acidity of solution and the carbon chain length of PFCAs. Mechanism of degradation of PFCAs (e.g. perfluorooctanoic acid (PFOA)) involved homolytic breakage of CC bond between alkyl and carboxyl groups, which produced radicals and subsequently decarboxylation to perfluoroheptene-1. Density functional theory (DFT) calculations supported the mechanism. The calculations indicated that a breaking of CC bond is more feasible with nondissociated HX than dissociated X^- species of PFCAs and also with increase in chain length. The potential of a combination of thermal- and photo-induced processes under acidic conditions to enhance degradation of PFOA in water is presented.

The use of carbon adsorbents for the removal of perfluoroalkyl acids from potable reuse systems

Bench- and pilot-scale sorption tests were used to probe the performance of several biochars at removing perfluoroalkyl acids (PFAA) from field waters, compared to granular activated carbon (GAC). Screening tests using organic matter-free water resulted in hardwood (HWC) (K_d = 41 L g^-1) and pinewood (PWC) (K_d = 49 L g^-1) biochars having the highest perfluorooctanoic acid (PFOA) removal performance that was comparable to bituminous coal GAC (K_d = 41 L g^-1). PWC and HWC had a stronger affinity for PFOA sorbed in Lake Mead surface water (K_F = 11 mg^(1-n) Lⁿ g^-1) containing a lower (2 mg L^-1) dissolved organic carbon (DOC) concentration than in a tertiary-filtered wastewater (K_F = 8 mg^(1-n) Lⁿ g^-1) with DOC of 4.9 mg L^-1. A pilot-scale study was performed using three parallel adsorbers (GAC, anthracite, and HWC biochar) treating the same tertiary-filtered wastewater. Compared to HWC, and anthracite, GAC was the most effective in mitigating perfluoropentanoic acid (PFPnA), perfluorohexanoic acid (PHxA), PFOA, perfluorooctane sulfonic acid (PFOS), and DOC (45-67% removed at 4354 bed volumes) followed by HWC, and then anthracite. Based on bench- and pilot-scale results, shorter-chain PFAA [perfluorobutanoic acid (PFBA), PFPnA, or PFHxA] were more difficult to remove with both biochar and GAC than the longer-chain, PFOS and PFOA.

The Role of Solvent-Accessible Leu-208 of Cold-Active Pseudomonas fluorescens Strain AMS8 Lipase in Interfacial Activation, Substrate Accessibility and Low-Molecular Weight Esterification in the Presence of Toluene

The alkaline cold-active lipase from Pseudomonas fluorescens AMS8 undergoes major structural changes when reacted with hydrophobic organic solvents. In toluene, the AMS8 lipase catalytic region is exposed by the moving hydrophobic lid 2 (Glu-148 to Gly-167). Solvent-accessible surface area analysis revealed that Leu-208, which is located next to the nucleophilic Ser-207 has a focal function in influencing substrate accessibility and flexibility of the catalytic pocket. Based on molecular dynamic simulations, it was found that Leu-208 strongly facilitates the lid 2 opening via its side-chain. The KM and Kcat/KM of L208A mutant were substrate dependent as it preferred a smaller-chain ester (pNP-caprylate) as compared to medium (pNP-laurate) or long-chain (pNP-palmitate) esters. In esterification of ethyl hexanoate, L208A promotes a higher ester conversion rate at 20 °C but not at 30 °C, as a 27% decline was observed. Interestingly, the wild-type (WT) lipase's conversion rate was found to increase with a higher temperature. WT lipase AMS8 esterification was higher in toluene as compared to L208A. Hence, the results showed that Leu-208 of AMS8 lipase plays an important role in steering a broad range of substrates into its active site region by regulating the flexibility of this region. Leu-208 is therefore predicted to be crucial for its role in interfacial activation and catalysis in toluene.

Removal of emerging perfluorooctanoic acid and perfluorooctane sulfonate contaminants from lake water

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are the major polyfluoroalkyl substances (PFASs) contaminating global water environment. This study investigated the efficiency of granular activated carbon (GAC), ultrafiltration (UF) and nanofiltration (NF) treatment for removing PFOS and PFOA contaminants from lake water. NF gave greater removal of all contaminant types (in terms of organic matter, PFOS and PFOA) than GAC treatment which in turn was greater than UF treatment. The lower removal by UF was due to larger pore size of the membrane compared to the size of the target contaminants. For all treatment processes, lower pH (4) in the feedwater showed greater rejection of the organics and selected PFASs. This was likely due to increase in the electrostatic repulsion between solute and sorbent. It could be observed that on increasing the concentration of organics in the feed solution, the rejection of PFOA/PFOS decreased which was due to competition between organics and PFOS/PFOA for binding sites on the membrane/activated carbon surface. It was also noted that protein content led to greater influence for lower rejection of the PFOA/PFOS than carbohydrate or DOC content. This study demonstrated the potential use of membrane processes for removing emerging persistent organic pollutant removal from lake water.

Mechanism insight of PFOA degradation by ZnO assisted-photocatalytic ozonation: Efficiency and intermediates

Zinc oxide (ZnO) nanorods were prepared by a directly pyrolysis method and employed as catalyst for perfluorooctanoic acid (PFOA) degradation. Comparative experiments were conducted to discuss the catalytic activity and flexibility of ZnO. After ZnO addition, the best PFOA degradation efficiency (70.5%) was achieved by ZnO/UV/O₃ system, only 9.5% by sole ozonation and 18.2% by UV₂₅₄ light irradiation. PFOA degradation was sensitive with pH value and temperature. The better PFOA removal efficiency was achieved at acidic condition. A novel relationship was found among PFOA degradation efficiency with hydroxyl radicals and photo-generated holes. Hydroxyl radicals generated on the surfaces of ZnO nanorods played dominant roles in PFOA degradation. PFOA degradation was found to follow the photo-Kolbe reaction mechanism. C₂-C₇ shorter-chain perfluorocarboxylic acids and fluoride ion were detected as main intermediates during PFOA degradation process. Based on the results, a proposal degradation pathway was raised.

Enhanced degradation of perfluorooctanoic acid using dielectric barrier discharge with La/Ce-doped TiO2

A synergistic system of dielectric barrier discharge (DBD) combined with La/Ce-TiO₂ was developed to investigate the decomposition performance of the environmentally persistent perfluorooctanoic acid (PFOA). The La/Ce-TiO₂ was modified by sol-gel method and characterized by XRD, SEM, and energy dispersive X-ray. The effects of PFOA concentration, applied voltage, initial pH, liquid conductivity, and additives on the removal rate of PFOA were explored. The results showed that the La/Ce-TiO₂ exhibited excellent catalytic effects on PFOA degradation in DBD system. When the applied voltage, PFOA concentration, pH value, and solution volume were 75 V, 100 mg/L, 3.63, and 1000 mL, respectively, the removal efficiency of PFOA was up to 97.5% by adding La₄Ce₁-TiO₂ in DBD. The corresponding defluorination ratio, TOC removal, and decomposition yield were 62.2%, 57.3%, and 37 g/kWh, respectively. Furthermore, five main intermediates including CF₃(CF₂)₆H, CF₃(CF₂)₅COOH, CF₃(CF₂)₅COH, CF₃(CF₂)₄COOH, and CF₃CF₂CF₃ were identified with LC-MS, and the degradation pathways of PFOA were proposed. The degradation mechanisms revealed that hydroxyl radicals play a significant role in the degradation of PFOA in the synergistic system.

Enhanced oral bioavailability of valsartan using a polymer-based supersaturable self-microemulsifying drug delivery system

A novel, supersaturable self-microemulsifying drug delivery system (S-SMEDDS) was successfully formulated to enhance the dissolution and oral absorption of valsartan (VST), a poorly water-soluble drug, while reducing the total quantity for administration. Poloxamer 407 is a selectable, supersaturating agent for VST-containing SMEDDS composed of 10% Capmul® MCM, 45% Tween® 20, and 45% Transcutol® P. The amounts of SMEDDS and Poloxamer 407 were chosen as formulation variables for a 3-level factorial design. Further optimization was established by weighting different levels of importance on response variables for dissolution and total quantity, resulting in an optimal S-SMEDDS in large quantity (S-SMEDDS_LQ; 352 mg in total) and S-SMEDDS in reduced quantity (S-SMEDDS_RQ; 144.6 mg in total). Good agreement was observed between predicted and experimental values for response variables. Consequently, compared with VST powder or suspension and SMEDDS, both S-SMEDDS_LQ and S-SMEDDS_RQ showed excellent in vitro dissolution and in vivo oral bioavailability in rats. The magnitude of dissolution and absorption-enhancing capacities using quantity-based comparisons was in the order S-SMEDDS_RQ > S-SMEDDS_LQ > SMEDDS > VST powder or suspension. Thus, we concluded that, in terms of developing an effective SMEDDS preparation with minimal total quantity, S-SMEDDS_RQ is a promising candidate.

Factors controlling the rate of perfluorooctanoic acid degradation in laccase-mediator systems: The impact of metal ions

This study investigated the factors that regulated the degradation of perfluorooctanoic acid (PFOA) in laccase-catalyzed oxidative humification reactions with 1-hydroxybenzotriazole (HBT) as a mediator. The reaction rates were examined under conditions with key factors varied, including initial PFOA concentrations, laccase and HBT dosages, and the ionic contents of the reaction solutions. The PFOA degradation followed pseudo-first order kinetics, and the rate constants (k) were similar for the high (100 μmol L^-1) and low (1.00 μmol L^-1) initial PFOA concentrations, respectively at 0.0040 day^-1 (r² = 0.98) and 0.0042 day^-1 (r² = 0.86) under an optimum reaction condition tested in this study. The metal ions contained in the reaction solution appeared to have a strong impact on PFOA degradation. Differential UV-Vis spectrometry revealed that Cu²⁺ can complex with PFOA, which plays an essential role to enable PFOA degradation, probably by bridging the negatively charged PFOA and laccase, so that the free radicals of HBT that are released from laccase can reach and react with PFOA. It was also found that Fe³⁺ plays a similar role as Cu²⁺ to enable PFOA degradation in the laccase-HBT reaction system. In contrast, Mg²⁺ and Mn²⁺ cannot complex with PFOA under the investigated conditions, and do not enable PFOA degradation in the laccase-HBT system. Fluoride and partially fluorinated compounds were detected as PFOA degradation products using ion chromatography and high resolution mass spectrometry. The structures of the products suggest the reaction pathways involving free-radical initiated decarboxylation, rearrangement, and cross-coupling.

Ultrasound pretreatment as a novel approach for intensification of lipase catalyzed esterification of tricaprylin

The current work deals with ultrasound assisted intensification of synthesis of tricaprylin based on the enzyme catalyzed reaction of caprylic acid and glycerol with novel approach of using ultrasound in only the initial stages of the reaction. Two types of immobilized lipases as Lipozyme RM (Rhizomucor miehei) and Novozym 435 (Candida antarctica) have been used in the work. The effect of ultrasonic conditions such as treatment time and power as well as the reaction conditions such as substrate molar ratio, reaction time and enzyme loading on the yield of tricaprylin has been investigated. It was established that the optimum pretreatment conditions were irradiation time as 30min with ultrasonic frequency of 20kHz, supplied power of 240W, 70% duty cycle (7s on 3s off cycle) whereas the optimum reaction conditions were 4:1 molar ratio of caprylic acid to glycerol, enzyme loading as 3% and operating temperature of 50°C. It was also established that reuse of enzymes for 10 cycles was possible without any significant effect on the activity of lipase. It was also conclusively established that compared to the conventional approach of synthesis, ultrasound pretreatment based approach greatly influenced the rate of reaction and maximum tricaprylin yield of 94.8% was achieved in 7h of reaction time under the optimum conditions.

Life cycle analysis of perfluorooctanoic acid (PFOA) and its salts in China

China has been the largest producer and emitter of perfluorooctanoic acid and its salts (PFOA/PFO). However, the flows of PFOA/PFO from manufacture and application to the environment are indistinct, especially flows from waste treatment sites to the environment. Here, a life cycle analysis of PFOA/PFO is conducted in which all major flows of PFOA/PFO have been characterized for 2012. Processes related to uses and possible releases of PFOA/PFO include manufacture and use, waste management, and environmental storage. During manufacture and use, emission from application was the most important (117.0 t), regardless of whether it flowed first to waste treatment facilities or was directly released to the environment, followed by manufacture of PFOA/PFO (3.9 t), while flows from the service life and end of life of consumer products were the lowest (1.2 t). Among five waste treatment routes, flows through wastewater treatment plants (WWTPs) were the highest (10.6 t), which resulted in 12.8 t of PFOA/PFO being emitted into the environment. Masses of PFOA/PFO emission were estimated to be 96.3 t to the hydrosphere, 25.6 t to the atmosphere, and 3.2 t to soils. Therefore, control over reduction of PFOA/PFO should focus on application of reliable alternatives and emission reduction from WWTPs using effective treatment techniques.

Molecular basis of P450 OleTJE: an investigation of substrate binding mechanism and major pathways

Cytochrome P450 OleT_JE has attracted much attention for its ability to catalyze the decarboxylation of long chain fatty acids to generate alkenes, which are not only biofuel molecule, but also can be used broadly for making lubricants, polymers and detergents. In this study, the molecular basis of the binding mechanism of P450 OleT_JE for arachidic acid, myristic acid, and caprylic acid was investigated by utilizing conventional molecular dynamics simulation and binding free energy calculations. Moreover, random acceleration molecular dynamics (RAMD) simulations were performed to uncover the most probable access/egress channels for different fatty acids. The predicted binding free energy shows an order of arachidic acid < myristic acid < caprylic acid. Key residues interacting with three substrates and residues specifically binding to one of them were identified. The RAMD results suggest the most likely channel for arachidic acid, myristic acid, and caprylic acid are 2e/2b, 2a and 2f/2a, respectively. It is suggested that the reaction is easier to carry out in myristic acid bound system than those in arachidic acid and caprylic acid bound system based on the distance of Hβ atom of substrate relative to P450 OleT_JE Compound I states. This study provided novel insight to understand the substrate preference mechanism of P450 OleT_JE and valuable information for rational enzyme design for short chain fatty acid decarboxylation.

Self-emulsifying drug delivery systems: Design of a novel vaginal delivery system for curcumin

AIM

The aim of this study was to develop a vaginal self-emulsifying delivery system for curcumin being capable of spreading, of permeating the mucus gel layer and of protecting the drug being incorporated in oily nanodroplets towards mucus interactions and immobilization.

METHODS

The emulsifying properties of curcumin loaded SEDDS containing 30% Cremophor RH40, 20% Capmul PG-8, 30% Captex 300, 10% DMSO and 10% tetraglycol (SEDD formulation A) as well as 25% PEG 200, 35% Cremophor RH40, 20% Captex 355, 10% Caprylic acid and 10% Tween 80 (SEDD formulation B) after diluting 1+2 with artificial vaginal fluid were characterized regarding droplet size and zeta potential. Collagen swelling test was used to examine the irritation potential of SEDDS. Additionally to mucus binding studies, permeation studies in the mucus were performed. Furthermore, spreading potential of the novel developed formulations was compared with a commercial available o/w cream (non-ionic hydrophilic cream) on vaginal mucosa.

RESULTS

SEDDS displayed a mean droplet size between 38 and 141nm and a zeta potential of -0.3 to -1.6mV. The collagen swelling test indicated no significant irritation potential of both formulations over 24h. An immediate interaction of unformulated curcumin with the mucus was determined, whereas both SEDDS facilitated drug permeation through the mucus layer. Formulation B showed a 2.2-fold improved transport ratio of curcumin compared to SEDD formulation A. In comparison to the vaginal cream, SEDD formulation A and B were able to spread over the vaginal mucosa and cover the tissue to a 17.8- and 14.8-fold higher extent, respectively.

CONCLUSION

According to these results, SEDDS seems to be a promising tool for vaginal application.

Identify biosorption effects of Thiobacillus towards perfluorooctanoic acid (PFOA): Pilot study from field to laboratory

The concentration of Perfluoroalkyl acids (PFAAs) and the bacterial community composition along the Xiaoqing River were explored with HPLC-MS/MS and Illumina high-throughput sequencing in present study. The results showed that perfluorooctanoic acid (PFOA) was the predominant PFAAs in all sediment samples, and high level of PFOA could lead to an evident increase in the abundance of Thiobacillus. Thiobacillus was identified with the survival ability in high concentrations of PFOA accordingly. Therefore, Thiobacillus thioparus and Thiobacillus denitrificans were selected as receptors to design indoor biosorption experiment. The growth curves under different PFOA concentrations and residual rates of PFOA in the processes of cultivation were analyzed. The results showed that upwards concentrations of PFOA below 5000 ng/L led to an obvious increase in the growth rate of T. thioparus. Whereas PFOA promoted the growth of T. denitrificans in a relatively limited range of concentration, and the effect was not obvious. The addition of different concentrations of PFOA had no apparent effects on pH values in the media of both T. thioparus and T. denitrificans. The concentrations of PFOA in liquid media reduced after the process of bacteria culturing. The removal rates of T. thioparus and T. denitrificans to PFOA were 21.1-26.8% and 13.5-18.4%, respectively. The current findings indicated that T. thioparus could play a significant role as potential biosorbent with the ability to eliminate PFOA effectively in aquatic environment, which would provide novel information for PFOA ecological decontamination and remediation.

Deriving environmental quality standards for perfluorooctanoic acid (PFOA) and related short chain perfluorinated alkyl acids

The evidence that in Northern Italy significant sources of perfluoroalkylacids (PFAA) are present induced the Italian government to establish a Working Group on Environmental Quality Standard (EQS) for PFAA in order to include some of them in the list of national specific pollutants for surface water monitoring according to the Water Framework Directive (2000/60/EC). The list of substances included perfluorooctanoate (PFOA) and related short chain PFAA such as perfluorobutanoate (PFBA), perfluoropentanoate (PFPeA), perfluorohexanoate (PFHxA) and perfluorobutanesulfonate (PFBS), which is a substitute of perfluorooctanesulfonate. For each of them a dossier collects available data on regulation, physico-chemical properties, emission and sources, occurrence, acute and chronic toxicity on aquatic species and mammals, including humans. Quality standards (QS) were derived for the different protection objectives (pelagic and benthic communities, predators by secondary poisoning, human health via consumption of fishery products and water) according to the European guideline. The lowest QS is finally chosen as the relevant EQS. For PFOA a QS for biota was derived for protection from secondary poisoning and the corresponding QS for water was back-calculated, obtaining a freshwater EQS of 0.1μgL^-1. For PFBA, PFPeA, PFHxA and PFBS threshold limits proposed for drinking waters were adopted as EQS.

Effects of carbohydrate/protein ratio on the microstructure and the barrier and sorption properties of wheat starch-whey protein blend edible films

BACKGROUND

Starch and whey protein isolate and their mixtures were used for making edible films. Moisture sorption isotherms, water vapour permeability, sorption of aroma compounds, microstructure, water contact angle and surface properties were investigated.

RESULTS

With increasing protein content, the microstructure changes became more homogeneous. The water vapour permeability increases with both the humidity gradient and the starch content. For all films, the hygroscopicity increases with starch content. Surface properties change according to the starch/whey protein ratio and are mainly related to the polar component of the surface tension. Films composed of 80% starch and 20% whey proteins have more hydrophobic surfaces than the other films due to specific interactions.

CONCLUSIONS

The effect of carbohydrate/protein ratio significantly influences the microstructure, the surface wettability and the barrier properties of wheat starch-whey protein blend films. © 2016 Society of Chemical Industry.

Removal of perfluorooctanoic acid (PFOA) in groundwater by nanofiltration membrane

Perfluorooctanoic acid (PFOA) is very persistent in the environment and resistant to typical degradation processes. PFOA has been widely used in surface-active agents and as an emulsifier in several products and can contaminate groundwater. Groundwater is considered as an important source of water; hence removal of PFOA contamination in groundwater is needed. This study aimed to examine the removal of PFOA in spiked deionized water and spiked groundwater samples by nanofiltration (NF) membrane. PFOA removal efficiency was performed by using NF membrane and all samples were analysed by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). For groundwater concentration, solid phase extraction is needed before being analysed by HPLC-MS/MS. The results showed that at higher pressures and higher PFOA concentrations, the PFOA removal efficiencies were slightly higher. The PFOA removal efficiency of spiked deionized water and spiked groundwater sample were 99.78-99.87% and 99.49-99.54%, respectively, which were not significantly different.