Effects of basic modifiers on sfe efficiencies of ephedrine derivatives from plant matrix

The effect of basified modifiers in supercritical CO₂ (SCF-CO₂) such as diethylamine has been investigated on the SFE efficiencies of ephedrine derivatives (e.g. methylephedrine, norephedrine, ephedrine, and pseudoephedrine) from aerial parts ofEphedra sinica. The addition of basified modifiers in SCF-CO₂ showed a greater enhancement of SFE efficiency of ephedrine derivatives than pure modifiers. These results might be due to the fact that the salts ofEphedra alkaloids (insoluble in CO₂) in plant tissues would be changed to their free bases (freely soluble in CO₂) by basified modifiers such as diethylamine in methanol. In addition to enhancing the solubilities, it could increase the degree of desorption of the compounds from plant matrix. Also, the SCF-CO₂ modified with methanol basified with diethylamine showed a difference of extractability of ephedrine and its diastereomer, pseudoephedrine. This paper was presented at The 5th International Symposium on Separation Technology-Korea and Japan held at Seoul between August 19 and 21, 1999.     

Preliminary separation and purification of rutin and quercetin from Euonymus alatus (Thunb.) Siebold extracts by macroporous resins

In this study, the performances of rutin and quercetin from Euonymus alatus (Thunb.) Siebold extracts on five macroporous resins with different physical and chemical properties were investigated. The results of static tests indicated that AB-8 resin was the most appropriate and its adsorption data were well fitted to the Langmuir and Freundlich isotherms. In order to optimize the separation process, different pH values of sample solution, different concentrations and pH values of ethanol solution also have been investigated. Column packed with AB-8 resin was used to perform dynamic adsorption and desorption experiments. After the treatment with AB-8 resin and optimal conditions, the contents of rutin and quercetin in the product were 8.45-fold and 13.14-fold increased with recovery yields of 63.1% and 72.3%, respectively. The results showed that the present method was suitable for large-scale preparation of rutin and quercetin from Euonymus alatus (Thunb.) Siebold or other herbal materials.     

Effect of operating conditions in removal of arsenic from water by nanofiltration membrane

The removal of arsenic from synthetic waters and surface water by nanofiltration (NF) membrane was investigated. In synthetic solutions, arsenic rejection experiments included variation of arsenic retentate concentration, transmembrane pressure, crossflow velocity and temperature. Arsenic rejection increased with arsenic retentate concentration. Arsenic was removed 93-99% from synthetic feed waters containing between 100 and 382 μg/L as V, resulting in permeate arsenic concentrations of about 5 μg/L. Under studied conditions, arsenic rejection was independent of transmembrane pressure, crossflow velocity and temperature. In surface water, the mean rejection of As V was 95% while the rejection of sulfate was 97%. The co-occurrence of dissolved inorganics does not significantly influence arsenic rejection. The mean concentration of As in collected permeated was 8 μg/L. The mean rejection of TDS, total hardness and conductivity were 75, 88 and 75% respectively.     

Bioethanol production from corn meal by simultaneous enzymatic saccharification and fermentation with immobilized cells of Saccharomyces cerevisiae var. ellipsoideus

The simultaneous enzymatic saccharification and fermentation (SSF) of corn meal using immobilized cells of Saccharomycescerevisiae var. ellipsoideus yeast in a batch system was studied. The yeast cells were immobilized in Ca-alginate by electrostatic droplet generation method. The process kinetics was assessed and determined and the effect of addition of various yeast activators (mineral salts: ZnSO₄ · 7H₂O and MgSO₄ · 7H₂O, and vitamins: Ca-pantothenate, biotin and myo-inositol) separately or mixed, was investigated. Taking into account high values of process parameters (such as ethanol concentration, ethanol yield, percentage of the theoretical ethanol yield, volumetric productivity and utilized glucose) and significant energy savings the SSF process was found to be superior compared to the SHF process. Further improvement in ethanol production was accomplished with the addition of mineral salts as yeast activators which contributed to the highest increase in ethanol production. In this case, the ethanol concentration of 10.23% (w/w), percentage of the theoretical ethanol yield of 98.08%, the ethanol yield of 0.55 g/g and the volumetric productivity of 2.13 g/l·h were obtained.     

In situ UV-vis spectroelectrochemistry of poly(o-phenylenediamine-co-m-toluidine)

Results of in situ UV-vis spectroelectrochemical studies of the electropolymerization of o-phenylenediamine (OPD), m-toluidine (MT) and the copolymerization of OPD with MT are reported. Electropolymerization was performed in aqueous acidic medium at a constant potential of E_SCE = 1.0 V at an indium doped tin oxide (ITO) coated glass electrode. The course of homopolymerization was followed for MT and OPD solutions with various monomer concentrations. The spectral characteristics of the mixed solutions were studied at a constant concentration of MT and various concentrations of OPD in the comonomer feed. An absorption band at λ = 497 nm was assigned to the head-to-tail mixed dimer/oligomer resulting from the cross reaction between OPD and MT cation radicals. UV-vis spectra recorded during copolymerization show dependence of the growth of the band at λ = 497 nm on OPD concentration in the feed. At lower OPD feed concentration it appears as the major band in the corresponding spectra. The UV-vis spectra recorded for the copolymer films suggest the incorporation of both monomer units in the copolymer. The FT-IR spectra of the copolymers show the presence of phenazine type structures in the copolymer backbone.     

Structural and property changes during uniaxial drawing of ethylene-tetrafluoroethylene copolymer films as analyzed by in-situ X-ray measurements

The structure-property relationship during uniaxial drawing of high-molecular-weight ethylene-tetrafluoroethylene copolymer (ETFE) film was analyzed based on a combination of in-situ wide-angle X-ray diffraction (WAXD) and stress measurements. In-situ WAXD patterns indicated that the hexagonal (100) reflection transformed from the initial un-oriented ring into equatorial spots via split arcs at temperatures both below and above T_g, but that the critical strain when such transition occurred was delayed above T_g. Drawing above T_g produced an equatorial concentration of the spot reflections; thus, the extended chain crystal was enhanced as a result of elongation of the strain-hardening region. In contrast, the draw below T_g remained less oriented even just before breaking. However, the high orientation component also appeared beyond the critical strain; it could be assigned to the so-called “tie molecules” that bind the deformed lamellae. Changes in resultant tensile strength could be interpreted by these extended chain crystals and characteristic tie molecule components.     

Synthesis of electrically conducting copolymers of aniline with o/m-amino benzoic acid by an inverse emulsion pathway

Copolymers of aniline and ortho/meta-amino benzoic acid were synthesized by chemical polymerization using an inverse emulsion pathway. The copolymers are soluble in organic solvents, and the solubility increases with the amino benzoic acid content in the feed. The reaction conditions were optimized with emphasis on high yield and relatively good conductivity (2.5×10⁻¹ S cm⁻¹). The copolymers were characterized by a number of techniques including UV-vis, FT-IR, FT-Raman, EPR and NMR spectroscopy, thermal analysis, SEM and conductivity. The influence of the carboxylic acid group ring substituent on the copolymers is investigated. The spectral studies reveal that the amino benzoic acid groups restrict the conjugation along the polymer chain. The SEM micrographs of the copolymers reveal regions of amorphous and crystalline domain. Thermal studies indicate a marginally higher thermal stability for poly(aniline-co-m-amino benzoic acid) compared to poly(aniline-co-o-amino benzoic acid).     

Ultrasonic and fermented pretreatment technology for diosgenin production from Diosorea zingiberensis C.H. Wright

The present study evaluated the efficiency of ultrasonic and fermented pretreatment technology for diosgenin production from Diosorea zingiberensis C.H. Wright (DZW). The optimum extraction conditions were as follows: ultrasonic pretreatment condition, 20 min, 50 kHz, 100 W; fermented pretreatment condition, 30 °C, 3 d and 0.8 g yeast dosages per 100 g raw materials; acidic hydrolysis condition, 1.5 mol/L sulfuric acid, 4 h; petrol extraction condition, 5 h. Under these conditions, diosgenin yield could reach 2.30%. Scanning electron micrographs indicated morphology changes of materials during diosgenin extraction process. UV-vis and GC-MS analysis revealed wastewater from the new approach contained 20 kinds of organic compounds which were mainly acids, esters, ketones and hydrocarbons. The research indicated the new approach could not only increase 42.5% diosgenin yield, recover 81.6% starch and 50.8% cellulose, but also efficiently reduce 69.7% COD, comparing with the conventional approach.     

Bioethanol production from wheat straw by the thermotolerant yeast Kluyveromyces marxianus CECT 10875 in a simultaneous saccharification and fermentation fed-batch process

Solid content in the simultaneous saccharification and fermentation (SSF) broth should be as high as possible in order to reach higher ethanol concentration. In this work, several feeding strategies for ethanol production from steam-exploded wheat straw by Kluyveromyces marxianus CECT 10875 have been studied with the aim of obtaining higher ethanol concentrations. Previous fermentability tests as well as SSF processes showed the difficulty of using the slurry for ethanol production under the studied conditions. Notwithstanding, fed-batch SSF processes with water-insoluble solids (WIS) fraction resulted in better configuration, reaching the highest ethanol concentration (36.2 g/L) with an initial WIS content of 10% (w/v) and 4% (w/v) of substrate addition at 12 h, which meant 20% more ethanol when compared with batch SSF.     

Evaluation of production and characterization of polygalacturonase by Aspergillus niger ATCC 9642

The aim of our study was to evaluate polygalacturonase (PG) production and characterization by Aspergillus niger ATCC 9642. The maximum PG activity (51.82 U/mL) was obtained using pectin, l-asparagine, and, iron sulphate concentrations of 32 g/L, 2 g/L, 0.06 g/L and 1.0 g/L, respectively; 180 rpm of stirring rate, 25 °C and an initial pH of 4.0. The kinetic study showed that the highest enzyme activity was achieved at 27 h of fermentation. The evaluation of the optimum pH and temperature permitted us to observe that highest PG activities were achieved at 37 °C and pH of 5.5. The enzymatic extract presented higher stability at 55 °C and pH of 5.0. The results showed that at low temperatures the enzyme extract kept the initial activity until 40 days of storage. The experimental design methodology permitted us to optimize the PG activity and an important aspect of this study is the characterization of the PG in terms of optimum temperature and pH using experimental design technique and also, the characterization of enzyme stability at low temperature. Such studies are very scarce in the literature and should be helpful to understand the true potentialities of pectinases in its industrial applications.     

Obtaining and characterization of biodiesel from jupati (Raphia taedigera Mart.) oil

The search for alternative triglyceride sources for biodiesel production is a widely discussed issue in Brazil because of the initiation of the Brazilian biofuel program. The viability of biodiesel production from the oil of Raphia taedigeraMart., commonly known as jupati, is studied in this work. This paper presents the obtention and characterization of biodiesel from jupati using an ethylic route with a methane sulfonic acid reaction catalyst. The alcohol:oil molar ratio was 9:1, and the catalyst concentration was 2% of the oil mass. The yield of the process was 92% by mass, and the oil conversion into jupati ethylic biodiesel was 99.6%. The physical and chemical parameters of jupati ethylic biodiesel were within the limits set by the National Agency of Petroleum, Natural Gas and Biofuels (ANP).     

Rich bioactive phenolic extract production by microbial biotransformation of Brazilian Citrus residues

Flavanones in Citrus are molecules that play an important role in antioxidant activities in nutraceutical products. Recent studies indicate that molecules of the simplest classes of phenolics have higher biological activity and absorption capacity. However, the molecules that have been shown to be very important bioactive compounds of Citrus, such as hesperetin, naringenin and ellagic acid, are found in trace concentrations in the fruit. An interesting environmentally friendly alternative that deserves attention regarding phenolic compound obtaining is the biotransformation of these molecules. The aim of this study was to develop a process of biotransformation of phenolics from Brazilian Citrus residues by solid-state fermentation with the microorganism Paecilomyces variotii. The optimized fermentation conditions were 10 g of Citrus residues (2.0 mm of substrate particle size), 20 mL distilled water, at 32 °C after 48 h of incubation. The development of this process has generated, simultaneously, an increase of 900, 1400 and 1330% of hesperetin, naringenin and ellagic acid concentration, respectively, and an increase of 73% of the antioxidant capacity. These results give strong evidence that microbial biotransformation does not only produce phenolic compounds but also compounds with high biological activity, such as hesperetin and naringenin.     

Enantioselective separation of R,S-phenylsuccinic acid by biphasic recognition chiral extraction

A new process has been developed to separate phenylsuccinic acid (H₂A) enantiomers, based on the oppositely preferential recognition of hydrophobic and hydrophilic chiral selectors in organic and aqueous phases, respectively, which is named as biphasic recognition chiral extraction (BRCE). BRCE system is established by adding hydrophobic l-iso-butyl tartrate in organic phase and hydrophilic β-cyclodextrin (β-CD) derivative in aqueous phase, which preferentially recognize S-H₂A and R-H₂A, respectively. The studies performed involve two enantioselective extractions in a biphasic system, where H₂A enantiomers form four complexes with β-CD derivative in aqueous phase and l-iso-butyl tartrate in organic phase, respectively. Here it is shown that the efficiency of the extraction depends, often strongly, on a number of process variables, including the types of organic solvents and β-CD derivatives, iso-butyl tartrate configurations, the concentrations of the extractants and H₂A enantiomers, pH and temperature. Phase-equilibria in BRCE systems is governed by the complex chemical equilibria in both the organic and aqueous phases. By changing the monophasic recognition chiral extraction (MRCE) system into BRCE system, the enantioselectivity increases from 1.501 to 2.862. The maximum enantioselectivity for H₂A enantiomers is obtained at pH≤2.5 and the ratio of 2:1 of [l-(+)-iso-butyl tartrate] to [HP-β-CD]. The experimental results show that BRCE is of much stronger chiral separation ability than MRCE, which is due to utilization of the separation abilities of both tartrate and β-CD derivative. It may be very helpful to optimize the extraction systems and realize the large-scale production of pure enantiomers.     

Evaluation of a novel low-cost culture medium containing exclusively milk,potato and glycerol for microbial transglutaminase production by Streptomyces mobaraensis

The aim of this work was to evaluate the production of microbial transglutaminase (MTG) by Streptomyces mobaraensis in a reduced nutritional medium based on non-commercial potatoes. Initially, the production was studied comparing 3 culture media based on potato: (i) media based on acid hydrolysed potato, (ii) media based on gelified non-hydrolysed potato and (iii) media based on gelified non-hydrolysed potato supplemented with glucose (20 g/L). All media were supplemented with nutrients and inductors of MTG production (yeast extract, peptone, sodium caseinate, glycerol and mineral salts such as sodium phosphate, potassium phosphate, magnesium sulphate). The best medium was gelified non-hydrolysed potato allowed to obtain up to 2.72 U/mL at 96 h. In a second study, it was proposed the substitution of all the nutrients and inductors by exclusively skim milk and glycerol. An experimental design was performed to optimize the composition of milk, potato and glycerol. The economical yield of the process was also evaluated. Fermentations were carried out and samples were taken at 72 h and 96 h. Results showed that the maximum MTG activity was obtained at 72 h. A significant effect of potato and milk on MTG activity was observed, including an effect of interaction between both compounds. Optimal conditions selected were: 600 g/L of skim milk, 40 g/L of potato and 5 g/L of glycerol, yielding a maximum activity of 3.2 U/mL and an economic yield of 8.11 € of MTG/€ of nutrients. The results showed that the medium milk–potato–glycerol was feasible for the production of transglutaminase, obtaining a high MTG activity in a simple natural medium.     

Optimization of biodiesel production from edible and non-edible vegetable oils

The non-edible vegetable oils such as Jatropha curcas and Pongamia glabra (karanja) and edible oils such as corn and canola were found to be good viable sources for producing biodiesel. Biodiesel production from different edible and non-edible vegetable oils was compared in order to optimize the biodiesel production process. The analysis of different oil properties, fuel properties and process parameter optimization of non-edible and edible vegetable oils were investigated in detail. A two-step and single-step transesterification process was used to produce biodiesel from high free fatty acid (FFA) non-edible oils and edible vegetable oils, respectively. This process gives yields of about 90-95% for J. curcas, 80-85% for P. glabra, 80-95% for canola, and 85-96% for corn using potassium hydroxide (KOH) as a catalyst. The fuel properties of biodiesel produced were compared with ASTM standards for biodiesel.     

Optimization of cultivation conditions for fungichromin production from Streptomyces padanus PMS-702

A novel strain, Streptomyces padanus PMS-702, was employed to produce fungichromin (FC, a polyene macrolide antibiotic) in a shake flask cultivation. In comparing the effects of various carbon and nitrogen sources on PMS-702 cultivation, it was found that glucose and soybean meal medium yielded the highest FC within 2 days. Factors such as medium composition, cultivation temperatures, and initial pH were optimized for FC production with response surface methodology (RSM). The optimal cultural condition obtained is as follows: glucose 11.2 g/L, soybean meal 11.2 g/L, CaCO₃ 0.46 g/L, temperature 31.7 °C, and an initial pH 5.5. Under these conditions, FC production reached 112 mg/L, about an increase of 2.86 times, as compared to results under basic conditions.     

Production of l-asparaginase from Escherichia coli ATCC 11303: Optimization by response surface methodology

This paper discusses the studies carried out for the optimal production of enzyme l-asparaginase (l-asparagine amidohydrolase, EC 3.5.1.1) from Escherichia coli (ATCC 11303). It was found that inoculum age of 18 h and inoculum size of 10% were the most favorable operating conditions for enzyme production. Lactose, yeast extract and KH₂PO₄ were found to be the best carbon, nitrogen and ion sources, respectively. Statistical method was used to survey how various medium conditions affect the enzyme production. By response surface methodology, the values of lactose, tryptone, yeast extract, KH₂PO₄ and l-asparagine concentration were investigated to obtain the maximum enzyme activity. The highest enzyme activity, 1.03 U mL⁻¹ enzyme, was determined under the following conditions: 1.08% lactose, 1.79% tryptone, 1.6% yeast extract, 2% KH₂PO₄ and 0.19% l-asparagine. Response surface methodology proved to be a powerful tool in optimizing the medium and by this method, more than 10-fold (from 0.1 to 1.03 U mL⁻¹) enhancement in l-asparaginase activity was achieved as compared to that obtained in the basal medium (Luria-Bertani media, inoculum age of 24 h and inoculum size of 10%).     

Thermosensitive poly(allylamine)-g-poly(N-isopropylacrylamide): synthesis, phase separation and particle formation

Grafting of poly(N-isopropylacrylamide) (PNIPAAm) having carboxylic groups at one end onto poly(allylamine) (PAH) in the presence of water soluble carbodiimide has yielded PAH-g-PNIPAAm copolymers with grafting ratios of 50, 29 and 18, respectively. These thermosensitive copolymers exhibit a lower critical solution temperature (LCST) at 34 °C at a temperature increase cycle regardless of their grafting ratios, a temperature identical to that of PNIPAAm-COOH oligomers. Temperature cycling reveals completely reversible polymer aggregation and dissolution above and below the LCST, respectively. Much smaller particle sizes are observed by scanning force microscopy and transmission electron microscopy compared to dynamic light scattering. A porous sphere model is suggested to depict the structure of the particles formed above the LCST, by which the dependence of the particle sizes on their grafting ratios is interpreted taking into account the surface tension and the spatial aggregation distance. Finally, to demonstrate the capability of the copolymers being used as thermosensitive polyelectrolytes, assembly onto multilayers is conducted and the increase of layer thickness is confirmed by small angle X-ray scattering and ellipsometry characterizations.     

Upper critical solution temperature—type cononsolvency of poly(N,N-dimethylacrylamide) in water—organic solvent mixtures

The behaviour of linear poly(N,N-dimethylacrylamide) (PDMAM) chains was studied by turbidimetry and viscometry in mixtures of water with the polar organic solvents methanol, dioxane and acetone. The swelling-deswelling behaviour of PDMAM gels in the same solvent mixtures was also investigated. Contrary to the behaviour in water-methanol mixtures, in water-dioxane and water-acetone mixtures a significant shrinkage of polymer chains and deswelling of polymer gels, followed by phase separation, was observed for high organic solvent fractions. Cononsolvency phenomena were found to be temperature-dependent, as demixing occurred upon decreasing temperature. This upper critical solution temperature (UCST) phase separation behaviour in mixed solvents was studied by turbidimetry and compared to the well-known lower critical solution temperature (LCST) behaviour of poly(N-isopropylacrylamide) (PNIPAM) in similar solvents mixtures.     

Synthesis and characterization of bionanocomposites of poly(lactic acid) and TiO2 nanowires by in situ polymerization

Bionanocomposites from biopolymers and inorganic nanoparticles are of great interest for packaging materials due to their enhanced physical, thermal, mechanical, and processing characteristics. In this study, poly(lactic acid) (PLA) nanocomposites with covalent bonding between TiO₂ nanowire surface and PLA chains were synthesized through in situ melt polycondensation. Molecular weight, structure, morphology, and thermal properties were characterized. Fourier transform infrared spectroscopy confirmed that PLA chains were covalently grafted onto TiO₂ nanowire surface. Transmission electron microscopy images also revealed clearly a third phase presence on the nanowires after the grafting process. Those grafted PLA chains exhibited significantly increased glass transition temperature and thermal stability, compared with pure PLA. The weight-average molecular weight of PLA/2% TiO₂ nanowire bulk nanocomposites increased by 66% compared with that of pure PLA. The electron microscopy results showed that strong interfacial interaction and homogeneous distribution were achieved between inorganic nanowires and organic PLA matrix in the bulk nanocomposites. The PLA matrix in bulk nanocomposites exhibited elevated glass transition temperature and decreased crystallization ability as the TiO₂ nanowire concentrations were increased from 0 to 2%.