Supercritical fluid extraction of bacterial and archaeal lipid biomarkers from anaerobically digested sludge

Supercritical fluid extraction (SFE) was used in the analysis of bacterial respiratory quinone (RQ), bacterial phospholipid fatty acid (PLFA), and archaeal phospholipid ether lipid (PLEL) from anaerobically digested sludge. Bacterial RQ were determined using ultra performance liquid chromatography (UPLC). Determination of bacterial PLFA and archaeal PLEL was simultaneously performed using gas chromatography-mass spectrometry (GC-MS). The effects of pressure, temperature, and modifier concentration on the total amounts of RQ, PLFA, and PLEL were investigated by 23 experiments with five settings chosen for each variable. The optimal extraction conditions that were obtained through a multiple-response optimization included a pressure of 23.6 MPa, temperature of 77.6 °C, and 10.6% (v/v) of methanol as the modifier. Thirty nine components of microbial lipid biomarkers were identified in the anaerobically digested sludge. Overall, the SFE method proved to be more effective, rapid, and quantitative for simultaneously extracting bacterial and archaeal lipid biomarkers, compared to conventional organic solvent extraction. This work shows the potential application of SFE as a routine method for the comprehensive analysis of microbial community structures in environmental assessments using the lipid biomarkers profile.     

Supercritical fluid extracts with antioxidant and antimicrobial activities from myrtle (Myrtus communis L.) leaves. Response surface optimization

Supercritical Fluid Extraction (SFE) was used to obtain myrtle leaf extracts, and to study the antioxidant capacity (AOC) and in vitro antimicrobial activity of those extracts. To optimize the SFE operational conditions, the response surface methodology (RSM) was adopted. The parameters studied were: pressure (P), within the range 10 to 30 MPa; temperature (T), between 35 °C and 60 °C and supercritical carbon dioxide (SCCO₂) flow rate (Q) within the range 0.15 to 0.45 kg h⁻¹. The results show a good fit to the proposed model and the optimal conditions obtained (23 MPa, 45 °C, and SCCO₂ flow rate of 0.3 kg h⁻¹) were within the experimental range. The predicted values agreed with experimental ones, thus indicating the suitability of the RSM model for the optimization of the extraction conditions being investigated. With those values remaining constant, ethanol as a co-solvent was then studied. There was an observed rise in AOC as the amount of ethanol increased, within the range studied (0–30 wt% ethanol). The extract with the highest AOC was tested for its antimicrobial activity against gram-positive and gram-negative bacteria. The minimum inhibitory concentration (MIC) values obtained showed significant inhibitory effect against gram-positive bacteria.     

Supercritical fluid extracts from brown coal lithotypes and their group components—molecular composition of non-polar compounds

The two Tertiary brown coals, i.e. xylitic brown coal (XBC) and humodetritous brown coal (HBC), from the ‘Turów’ and ‘Konin’ deposits in Poland and their group components were investigated on their behaviour to Soxhlet and supercritical fluid (SFE process) extractions. The raw coals were Soxhlet pre-extracted to remove unbound lipids (bitumens). Humic acids, lignin and cellulose were obtained from the pre-extracted XBC, while humic acids and residual coal were separated from the HBC. Raw coals and their group components were extracted under supercritical conditions with toluene (653 K, 8 MPa, 1 h). The yield of non-polar fractions from the Soxhlet and supercritical extracts were determined and analysed by gas chromatography-mass spectrometry (GC-MS).The diversity in biomarker compositions (n-alkanes, n-alkylbenzenes, iso-alkanes, fatty acids, diterpanes and pentacyclic triterpanes and their aromatised derivatives, methylphenanthrenes) of the supercritical fluid extracts (SFEs) were compared and contrasted with the Soxhlet extracts. The biomarker geochemical indices in Soxhlet extracts are typical of low maturity, while these released by SFE process have characteristic of a higher maturation level. The Soxhlet extracts of both coals show a dominance of 17α(H),21β(H)-homohopane with the precursor configuration of 22R. The pentacyclic triterpanes found in the SFEs are diverse structures, i.e. 17α(H),21β(H)-hopanes, moretanes and small amounts of benzohopanes, as well as geochemically unaltered homohopane with the biological configuration of 17β(H),21β(H)-(22R). Isopimarane is the characteristic of SFEs from humic acids of the coals. Partially aromatised pentacyclic triterpanes related to α- and β-amyrin are characteristic of free lipids and SFEs of humic acid fractions from both coals. The diversity in the phenanthro[4,5-bcd]furan, methylphenanthrenes and 2-methylanthracene compositions is dependent on chemical nature of the brown coal group component.     

Supercritical fluid extraction of lycopene from tomato juice and characterization of its antioxidation activity

A new method to extract lycopene from tomato juice using supercritical CO₂ as solvent and without the need to dry the raw material is presented. To conduct the extraction, the tomato juice was subjected to cycles of centrifugation followed by rinsing with absolute ethanol to partially remove the water present in the solid part of the juice. The influence of the temperature and pressure on the extraction efficiency and on the extract antioxidant activity was studied using a factorial experimental design. The extraction efficiency varied from 7.7% to 76.7% and only extraction temperature had a statically significant effect on the process. The reversed phase HPLC analysis showed that lycopene is the major compound of the extract. The extract that presented higher antioxidant activity was obtained at 40 °C and 350 bar with 12.7 mmol L⁻¹ Trolox/g of extract using the DPPH radical scavenging method and 61.3 mmol L⁻¹ Trolox/g of extract using the rubrene singlet oxygen quenching method.     

Supercritical fluid extraction of flavonoids from Maydis stigma and its nitrite-scavenging ability

Supercritical fluid carbon dioxide (SF-CO₂) extraction (SFE) of flavonoids from Maydis stigma and its nitrite-scavenging ability were investigated. The effects of extraction time, particle size and co-solvent composition in terms of water content in ethanol were first optimized. Then, a Box-Behnken design combined with response surface methodology (RSM) was employed to study the effects of three independent variables (temperature, pressure and co-solvent amount) on the extraction yield of flavonoids. A maximal extraction yield of flavonoids of approximately 4.24 mg/g of M. stigma by SFE was obtained under optimal conditions (a temperature of 50.88 °C, a pressure of 41.80 MPa, a co-solvent amount of 2.488 mL/g and an extraction time of 120 min with 0.4-mm particle sizes and 20% aqueous ethanol as the co-solvent). Furthermore, the nitrite-scavenging ability of the flavonoid-enriched SFE extracts was assessed using the Griess reagent. The flavonoid-enriched SFE extracts exhibited the highest scavenging ability on nitrite (88.1 ± 3.04%) at the concentration of 500 μg/mL and at pH 3.0. The nitrite-scavenging ability of the extracts appeared to be concentration dependent but negatively correlated with the pH.     

Supercritical fluid extraction of volatile oil from Lippia alba (Mill.) cultivated in Aragón (Spain)

The objective of this study is the supercritical extraction of the volatile oil from Lippia alba (Mill.) cultivated in Aragón. The influence of extraction pressure and temperature and cosolvent percentage on overall yield and volatile oil composition was studied. The supercritical extraction conditions were optimized using the 2007 crop; operating at 35.0 MPa, 40 °C and 5% of ethanol as cosolvent, 2009 and 2011 crops were also tested. Supercritical fluid extract compositions and overall yields were compared with the extracts obtained by conventional extraction techniques such as hydrodistillation (HD) and organic solvent extraction (OSE). Four terpenoids (linalool, 1,8-cineole, β-caryophyllene and β-caryophyllene oxide) were selected as target compounds and their content in the different extracts was monitored by gas chromatography. Linalool was selected as indicator of the plant adaptation to the commercial purposes. HD is the technique that provides the highest percentage of linalool in all the extracts, but showed always the lowest overall yields; whereas, SFE extracts provides a good balance between the overall yield and presence of the four target compounds.     

Synthesis of bis(2,4-diphenylbutyl) phthalate and its application as a plasticizer for poly(vinyl chloride) from waste polystyrene

Bis(2,4-diphenylbutyl) phathalate, a plasticizer for poly(vinyl chloride) (PVC), was synthesized from 2,4-diphenyl-1-butene obtained by a thermal decomposition under reduced pressure of waster polystyrene. The heat stability of bis(2,4-diphenylbutyl) phthalate was determined by thermogravimetric analysis and compared with typical plasticizers. It was recognized that bis(2,4-diphenylbutyl) phthalate showed high heat resistant. A test sheet of plasticized PVC with bis(2,4-diphenylbutyl) phthalate and bis(2-ethylhexyl) phthalate was prepared. The test sheet was used for determination of the plasticizing performance of bis(2,4-diphenylbutyl) phthalate. Although the effect of bis(2,4-diphenylbutyl) phthalate imparting flexibility to PVC is poorer than that of bis(2-ethylehexyl) phthalate, the former phthalate is well compatible with PVC and exceedingly heat-resistant.     

Proximal composition, lipid and cholesterol content of meat from pigs fed peach-palm meal (Bactris gasipaes Kunth) and synthetic lysine

Two experiments were conducted to evaluate the proximal composition, lipids and cholesterol content of meat from pigs fed diets with peach-palm meal (PPM), with or without addition of synthetic lysine (LYS). In experiment 1, 24 pigs were randomly allotted into six treatments with three levels of PPM (0.16 and 32%) and two levels of LYS (0 and 0.27%). In experiment II, 16 finishing pigs were fed with two levels of PPM (0 and 17.50%) and two levels of LYS (0 and 0.27%). At the end of each experiment (42 and 35 d, respectively), pigs were slaughtered and loin samples were obtained to determine crude protein, dry matter, moisture, ash, total lipids, and cholesterol content. In experiment I, pork loin from 16% PPM had more dry matter (26.45 g/100 g) and less moisture (73.49 g/100g) than pork loin from 32% PPM (25.11 y 75.03 g/100g, respectively). Meat samples from pigs without LYS had higher (p < 0.05) content of lipids (2.11 g/100 g) than meat from pigs that consumed LYS (1.72 g/100 g). In experiment II, the proximal, lipids and cholesterol content were similar among treatments. The PPM addition to pig diets did not affect the proximal composition of pork, while LYS addition indicated a reduction of total lipids, which could result as an alternative to obtain leaner meat.     

Synthesis of low molecular weight poly(vinyl acetate) and its application as plasticizer

Poly(vinyl acetate), PVAc, with a degree of polymerization X_n = 10 was prepared by chain‐transfer radical polymerization using carbon tetrachloride and used as oligomeric plasticizer for commercial PVAc. However, the chlorinated chain ends cause a low thermal stability requiring mild Cl/H substitution. The product exhibits high thermal stability and excellent melt‐compounding properties. Blends of oligomeric and commercial PVAc show single glass transition temperatures which decrease with higher oligomer content and exhibit small negative deviations from Fox' linear additivity rule. This indicates plasticization and miscibility being mainly due to entropic effects. Injection‐moulded thick specimens show ductile behaviour at oligomer contents >10 wt %, while sheets with a thickness of 0.2–0.5 mm appear flexible already at 7.5 wt %. The oxygen permeability coefficients are an order of magnitude lower than those of low‐density polyethylene. Due to the sum of their properties, the plasticized sheets present a promising alternative in the preparation of barrier materials. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40226.     

Facile synthesis of crystalline nanoporous Mg3(PO4)2 and its application to aerobic oxidation of alcohols

Nanoporous crystalline Mg₃(PO₄)₂ material was synthesized by a simple hydrothermal method using Poly ethylene glycol (PEG) as a template. The material was thoroughly characterized by XRD, FTIR, DT/TGA, CO₂-TPD, SEM, TEM, N₂ sorption and was readily explored for the industrially important oxidation of alcohols at solvent-less liquid phase aerobic conditions. At 100 °C and 4 bar pressure, the material successfully produced benzaldehyde (88% selectivity). The material also exhibited reusability and reaction time stability properties desired for industrial applications. The subject gains novelty in terms of the synthesis of nanoporous crystalline Mg₃(PO₄)₂ material as well as its first of its kind application to aerobic oxidation.     

Synthesis of 1,2-bis(2-oxazolinyl-2)ethane and its application as chain extender for poly(ethylene terephthalate)

Summary The reaction of ethanolamine (EA) with nitriles is a general route to prepare oxazolines. However, in case of vicinal nitrile groups, cyclic imidines are formed. It is shown, that succinonitrile gives with EA mainly 1-(hydroxyethyl)-2,5-bis-(hydroxyethylimine) azacyclopentane (= triol). The corresponding 1,2 bis-(2-oxazolinyl-2) ethane (BOXE) is formed by heating the triol. BOXE can be used as chain extender of poly(ethylene terephthalate) (PET). If PET is heated with BOXE at 270 °C the viscosity increases first. However, on prolonged heating the viscosity decreases again, which can not be ascribed to the normal degradation processes. Therefore, a mechanism is proposed in which the chain scission takes place in the newly formed bridge.     

Characterization of sulfonated poly(styrene–divinylbenzene) and poly(divinylbenzene) and its application as catalysts in esterification reaction

Polymeric supports based on divinylbenzene (DVB) were prepared by aqueous suspension polymerization in presence or absence of styrene (S), using toluene and n‐heptane as diluents of the monomers. Poly(S–DVB) and poly(DVB) were sulfonated with sulfuric acid in presence of 1,2‐dichloroethane. The influence of the morphological structure of the supports and as a consequence of the catalyst on the esterification reaction of acetic acid with n‐butanol was evaluated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3616–3627, 2006     

Synthesis of zeolite Na-P1 from coal fly ash produced by gasification and its application as adsorbent for removal of Cr(VI) from water

The coal fly ash produced by gasification is estimated to be over 80 million ton per year in China by 2021. It has mainly been disposed as solid waste by landfill. There is lack of study focused on its utilization. In this paper, the coal fly ash produced by gasification was at first analyzed and then applied to synthesize zeolite as an adsorbent. The effects of synthesis conditions on the cation exchange capacity (CEC) of zeolite were investigated. The results from X-ray diffraction and scanning electron microscope indicated that the crystallinity of the synthesized zeolite is the most important factor to affect the CEC. When the synthesized zeolite with the highest CEC (275.5 meq/100 g) was used for the adsorption of Cr(VI) from aqueous solution, the maximum adsorption capacity for Cr(VI) was found to be 17.924 mg/g. The effects of pH, contact time and initial concentration on the adsorption of Cr(VI) were also investigated. The adsorption kinetics and isotherms can be well described by the pseudo-second-order model and Langmuir isotherm model, respectively.     

Preparation and characterization of hyperbranched poly(ether sulfone) and its application as a coating additive for linear poly(ether sulfone)

Hyperbranched poly(ether sulfone) (HPES), a suitable coating additive for improving the rheological properties of linear poly(ether sulfone) (LPES), was easily produced via polymerization of commercially available bisphenol S (A₂ monomer, BPS) and synthesized 2,4′,6‐trifluoro‐phenylsulfone (BB′₂ monomer, TF). During this reaction, fluoro‐ or phenolic‐terminated HPES (F‐HPES or OH‐HPES) could be facilely obtained by controlling the feed mole ratios of the two monomers. The polymerization mode A₂ + BB′₂ was confirmed by analyzing the model compounds and the degree of branching (DB) was calculated systematically. In addition, the synthesized polymers' chemical structures were exhibited by FTIR, ¹H NMR as well as ¹⁹F NMR spectroscopy. Notably, the addition of 1 wt % HPES reduced the melt viscosity and improved the high temperature liquidity of LPES because of its unique spherical shape. Furthermore, the addition of HPES did not have a negative impact on the performance of LPES, which was attributed to the good miscibility between HPES and LPES. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43892.     

Electrochemical preparation of poly(o‐toluidine) film and its application as a permselective membrane

Poly(o‐toluidine) films were electrochemically synthesized on Pt electrodes at a constant potential (0.75 V versus Ag/AgCl) from a deoxygenated aqueous solution of 0.1M toluidine dissolved in 0.1M KCl. To form permselective polymeric film electrodes, poly(o‐toluidine) films at different thicknesses were prepared by varying the amount of charge consumed during electrochemical polymerization. Then, experimental parameters (e.g., concentrations of monomer and electrolyte and pH of the phosphate buffer salt solution) affecting the polymeric film thickness were optimized. Permeation of the various electroactive and nonelectroactive species such as ascorbic acid, oxalic acid, hydrogen peroxide, lactose, sucrose, and urea through the optimized poly(o‐toluidine)‐coated electrodes was investigated using a chronoamperometric technique. From experimental results, it was found that a poly(o‐toluidine)‐coated electrode permitted the oxidation of hydrogen peroxide and prevented the permeation of the mentioned electroactive and nonelectroactive species. In other words, it was seen that this polymeric electrode responded to only hydrogen peroxide selectively. Thus, it has been claimed that a poly(o‐toluidine)‐coated Pt electrode can be used as a permselective polymeric membrane to overcome interference problems occurring in the hydrogen peroxide‐based biosensor applications. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 2141–2146, 1999     

Supercritical fluid extraction of peach (Prunus persica) almond oil: Kinetics, mathematical modeling and scale-up

Peach almonds contain oil with important therapeutic and nutritional properties due to the presence of unsaturated fatty acids, high content of oleic acid and other substances. In this study, peach almond oil was obtained by means of supercritical fluid extraction (SFE), with yield up to 24% w/w. The objective of this work was to evaluate the effect of the operation variables in the process kinetics in order to define scale-up parameters, like extractor volume and solvent flow rate. In spite of the importance for industrial application, the definition of a scale-up methodology is difficult. Therefore, the main goal of this work was to study the kinetic aspects of the SFE by modeling the extraction curves and, with these results, suggests a scale-up methodology. The parameters evaluated were extraction pressure, CO₂ flow rate and particle size. The mass transfer models used to describe the extraction curves were logistic model, diffusion model and Sovová model. Four scale-up methodologies, based on mass transfer mechanisms, were applied. The results indicate the best curve fitting by means of Sovová’s model, while the best scale-up criterion was maintaining the ratio Q_CO2/M (solvent flow rate/raw material mass) constant. This study also indicated the convection as the dominant mass transfer mechanism, while the diffusion was the limiting factor. Moreover, the SFE of peach almond oil could be predicted by the scale-up method used.     

9,9-双（甲氧基甲基）芴的合成及其应用研究

9,9-双（甲氧基甲基）芴（BMMF）的合成分两步进行：首先,在乙醇钠催化剂的作用下,芴与多聚甲醛反应合成了中间体9,9-双（羟甲基）芴（BHMF）,然后以四丁基溴化铵（TBAB）为相转移催化剂,再与氯甲烷发生烷基化反应合成了9,9-双甲氧基甲基芴。用9,9-双（羟甲基）芴作外给电子体进行了丙烯聚合应用,实验结果表明：9,9-双（甲氧甲基）芴（BMMF）是聚丙烯Ziegler-Natta催化体系较好的外给电子体。