OPTIMIZATION OF LARGE VOLUME INJECTION FOR IMPROVED DETECTION OF POLYCYCLIC AROMATIC HYDROCARBONS (PAH) IN MUSSELS

Detection of PAH of six benzene rings is somewhat troublesome and lowering the limits of detection (LODs) for these compounds in food is necessary. For this purpose, we optimized a Programmable-Temperature-Vaporisation (PTV) injection with Large Volume Injection (LVI) with regard to the GC-MS detection of anthracene, benz[a]anthracene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene and dibenzo[a,e]pyrene. The optimization of PTV-LVI for GC-MS analysis included the choice of liner, solvent venting, splitless time, split flow and initial inlet temperature for injection of 25 μ L standard solution and spiked mussel samples. Samples were extracted with Accelerated Solvent Extraction (ASE) followed by two semi-automatic clean-up steps; gel permeation chromatography (GPC) on S-X3 and solid phase extraction (SPE) on pre-packed silica columns, prior to gas chromatography-mass spectrometry (GC-MS) detection. In comparison to traditional splitless injection, LODs were lowered for eighteen PAHs by the use of PTV-LVI ranging from 0.05 μ g kg ^?1 to 1.0 μ g kg^?1 fresh weight. In particular, the LOD of dibenzo[a,e]pyrene was improved by a factor of ten when using the validated PTV-LVI method.     

POLYCYCLIC AROMATIC HYDROCARBONS ANALYZED IN RAINWATER COLLECTED ON TWO SITES IN EAST OF FRANCE (STRASBOURG AND ERSTEIN)

Polycyclic Aromatic Hydrocarbons (naphtalene, acenaphtene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, benzo[j]fluoranthene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, benzo[g,h,i]perylène, indeno[1,2,3-c,d]pyrene and coronene) have been consecutively analyzed in rainwater sampled in Strasbourg (urban site) and Erstein (rural site) between January 2002 and June 2003 and between April 2002 and June 2003 on a weekly basis respectively. For the sampling of rainwater, a wet-only rainwater sampler was used together with an open collector to take the measurements of precipitation.

PAHs in rainwater were extracted by using SPE cartridges and analyzed by HPLC-fluorescence following a method developed in the laboratory.

Mean concentrations of all PAHs (Σ 16 HAPs) varied between 0.15 and 79.60 ng·L^?1 in Erstein, and between 3.70 and 1596.45 ng·L^?1 in Strasbourg. Naphtalene, phenanthrene, fluoranthene, pyrene, chrysene, benzo[j]fluoranthne and benzo[a]pyrene were the most concentrated PAHs analyzed. Benzo[a]pyrene was frequently detected. Seasonal effects were observed with a maximum of concentrations of PAHs during cold periods. Some spatial influences were also reported. The calculation of some PAH ratios show that diesel exhaust could be the main source of PAHs in rainwater on the two sites.     

Batch treatment of saline wastewater by Halanaerobium lacusrosei in an anaerobic packed bed reactor

BACKGROUND: This study considers batch treatment of saline wastewater in an upflow anaerobic packed bed reactor by salt tolerant anaerobic organisms Halanaerobium lacusrosei . RESULTS: The effects of initial chemical oxygen demand (COD) concentration (COD₀ = 1880–9570 mg L^?1), salt concentration ([NaCl] = 30–100 g L^?1) and liquid upflow velocity (V_up = 1.0–8.5 m h^?1) on COD removal from salt (NaCl)‐containing synthetic wastewater were investigated. The results indicated that initial COD concentration significantly affects the effluent COD concentration and removal efficiency. COD removal was around 87% at about COD₀ = 1880 mg L^?1, and efficiency decreased to 43% on increasing COD₀ to 9570 mg L^?1 at 20 g L^?1 salt concentration. COD removal was in the range 50–60% for [NaCl] = 30–60 g L^?1 at COD₀ = 5200 ± .100 mg L^?1. However, removal efficiency dropped to 10% when salt concentration was increased to 100 g L^?1. Increasing liquid upflow velocity from V_up = 1.0 m h^?1 to 8.5 m h^?1 provided a substantial improvement in COD removal. COD concentration decreased from 4343 mg L^?1 to 321 mg L^?1 at V_up = 8.5 m h^?1, resulting in over 92% COD removal at 30 g L^?1 salt‐containing synthetic wastewater. CONCLUSION: The experimental results showed that anaerobic treatment of saline wastewater is possible and could result in efficient COD removal by the utilization of halophilic anaerobic bacteria. Copyright © 2008 Society of Chemical Industry     

Optimization of the culture conditions for production of glutamate decarboxylase by Streptococcus salivarius ssp. thermophilus

The culture conditions for glutamate decarboxylase (GAD) production under submerged fermentation by Streptococcus salivarius ssp. thermophilus were investigated. The results indicated the optimum culture medium was composed as follows: 15.0 g L^?1 of peptone, 12.5 g L^?1 of beef extract, 12.5 g L^?1 of sucrose, 1.03 g L^?1 of dipotassium hydrogen phosphate, 5 g L^?1 of sodium acetate, 2 g L^?1 of ammonium dibasic citrate, 2.12 g L^?1 of calcium chloride, 1 g L^?1 of Tween 80, and initial pH 6.79. The optimum culture temperature and time were 37 °C and 12 h, respectively. Under these conditions, GAD production was 257.46 ± 5.12 U, which was about 1.45‐fold that of Man–Rogosa–Sharpe broth. Copyright © 2008 Society of Chemical Industry     

Effect of feed composition on PHB production from methanol by HCDC of Methylobacterium extorquens (DSMZ 1340)

BACKGROUND: Poly‐β‐hydroxybutyrate (PHB), produced by several species of bacteria, has attracted great attention as a biodegradable and biocompatible compound with similar properties to polypropylene. Unfortunately, its use is currently limited due to high production costs. One of the most common methods for overcoming this constraint is the use of inexpensive substrates, like methanol, in high cell density cultivations (HCDC). RESULTS: Fermentation was carried out with optimized feed composition (639 g l^?1 methanol, 4 g l^?1 MgSO₄.7H₂O, 41 mL L^?1 trace elements, 5.6 g L^?1 NaH₂PO₄.H₂O and 24.3 g L^?1 K₂HPO₄) and a feeding strategy based on the detection of substrate limitation by dissolved oxygen (DO). After 35 h, at which dry cell weight (DCW) reached a value of 70 g L^?1, PHB production was stimulated, and biomass and PHB productivities of 2.8 and 0.98 g L^?1 h^?1 were obtained, respectively. These results surpassed those reported in the literature for PHB production from methanol by Methylobacterium species. CONCLUSION: The proposed feed composition and feeding strategy for PHB production from methanol by Methylobacterium extorquens 1340 in fed‐batch cultivation resulted in high biomass and PHB productivity. They can be implemented for recombinant bioproducts (proteins) produced by M. extorquens due to the lack of PHB accumulation in the growth phase. Copyright © 2009 Society of Chemical Industry     

GAS-PARTICLE PARTITIONING OF POLYCYCLIC AROMATIC HYDROCARBONS DURING THE SPRING AND SUMMER IN A SUBURBAN SITE NEAR MAJOR TRAFFIC ARTERIES

Concentrations of atmospheric polycyclic aromatic hydrocarbons were measured in a suburban site near major traffic arteries during the period April-August 2006. Total suspended particulate during the sampling period was 65.3 ± 33.9 μ g m^?3. Total PAH concentrations were 63.5 ± 20.1 ng m^?3 in the gaseous phase and 1.4 ± 0.3 ng m^?3 in the particulate phase. Observed concentrations were comparable with previously measured values reported in the literature for urban and suburban sites with a high anthropic influence. PAH concentration diagnostic ratios indicate that, during the spring and summer seasons, vehicular emission was the main source of atmospheric PAHs.

Gas/particle partitioning coefficients K _P were well correlated with both the sub-cooled liquid vapor pressures p _L ⁰ and the octanol-air partition coefficients K _OA . Measured K _P values were in a good agreement with K _P values predicted by applying a literature model, which takes into account both adsorption onto black carbon and absorption into the organic matter.     

ALIPHATIC,POLYCYCLIC AROMATIC HYDROCARBONS AND NITRATED-POLYCYCLIC AROMATIC HYDROCARBONS IN PM 10 IN SOUTHWESTERN MEXICO CITY

A sampling campaign of airborne particles ≤ 10 μ m (PM ₁₀ ) was carried out from February to April of 2004 at the Universidad Nacional Autónoma de México in southwestern Mexico City. The average PM ₁₀ mass concentration was 51 ± 14 μ g m^?3. Extracted organic matter was determined, with a mean of 6.5 ± 1.7 μ g m^?3, which represents 12.9% of PM ₁₀ mass concentration. The standard additions method was used on real samples at four concentration levels for 13 n-alkanes, 14 PAHs and 5 nitro-PAHs. The average concentration for the sum was 99.04 ng m^{? 3} for n-alkanes, 4.9 ng m^?3 for PAHs and 710 pg m^{? 3} for nitro-PAHs. Higher concentrations of n-alkanes > C ₂₄ were found, indicating biogenic emissions as the dominant source. Coronene, benzo[ghi]perylene, benzo[b+j+k]fluoranthenes and indeno[1,2,3-cd]pyrene were the most abundant PAHs, suggesting a strong contribution from incomplete combustion of gasoline. The PAHs considered for calculating BaPE represented 52% of the total PAHs analyzed. The presence of 9-nitroanthracene indicates direct emission from diesel combustion and heterogeneous nitrating reactions on sorbed particles, while 2-nitrofluoranthene, indicates gas-phase reactions with fluoranthene, hydroxyl (OH^?) and/or nitrate (NO ₃ ^?) radicals in the presence of nitrogen oxides (NOx).     

Comparison of N-Heterocyclic Aromatics Dibenzo[c,g]Carbazole and Dibenz[a,j]Acridine : Metabolism,DNA Binding and Mutation

N-Heterocyclic aromatics, such as carbazole and acridine derivatives, are environmental carcinogenic pollutants. Examples of these compounds are 7H-dibenzo[c,g]carbazole (DBC) and dibenz[a,j]acridine (DBA). The ionization potential (IP) for DBC is lower than for DBA. DBC is metabolized in lung and liver by way of phenols or directly through radical cations. DBC-induced liver and lung tumors have mutations in the 61^st codon of ras. DBA is metabolized in skin by way of a diol-epoxide of DBA. DBA-induced skin tumors have mutations in 12^th, 13^th and 61^st codons of ras. In summary, the metabolic activation of DBC proceeds through different adduction pattern pathways than does DBA and leads to different ras mutational spectra.     

The effect of salinity on nitrite accumulation in a down‐flow hanging sponge reactor

BACKGROUND: In this study, the inductive effect of salinity on nitrite accumulation in a down‐flow hanging sponge (DHS) reactor, developed as a novel and cost‐effective wastewater treatment process, was evaluated by conducting a long‐term continuous experiment lasting more than 1400 days. RESULTS: The influent salinity was controlled by adding NaCl at concentrations ranging from 0 to 25 g Cl^? L^?1. The effluent nitrite increased with increases in salinity, i.e. the fraction of nitrite to total nitrogen in the effluent increased from 1.6% at 0 g Cl^? L^?1 to 87.6% at 25 g Cl^? L^?1. Fluorescence in situ hybridization (FISH) analysis revealed that as salinity increased, the nitrifying bacterial community in the DHS changed markedly at the species level. In particular, the dominant nitrite‐oxidizing bacteria changed from Nitrospira‐sublineage I at 0 g Cl^? L^?1 to Nitrobacter spp. at 15 g Cl^? L^?1. At 25 g Cl^? L^?1, no nitrite‐oxidizing bacteria were detected. CONCLUSION: Our findings suggest that the DHS reactor is suitable for cost‐effective nitrite production processes and that salinity control using NaCl is an effective method for inducing nitrite accumulation. Copyright © 2012 Society of Chemical Industry     

Magnetic molecularly imprinted polymer nanoparticles coupled with high performance liquid chromatography for solid‐phase extraction of carvedilol in serum samples

Herein, we report a magnetic molecularly imprinted polymers (m‐MIPs) using Fe₃O₄ as a magnetic component, carvedilol as a template molecule for the solid‐phase extraction (MISPE) as the sample clean‐up technique combined with high‐performance liquid chromatography (HPLC) and for the controlled release of carvedilol at different pH values of 1.0 (simulated gastric fluid), 6.8 (simulated intestinal fluid), and 7.4 (simulated biological fluid). The adsorption kinetics was modeled with the pseudo‐first‐order and pseudo‐second‐order kinetics, and the adsorption isotherms were fitted with Langmuir and Freundlich models. The performance of the m‐MIPs for the controlled release of carvedilol was assessed and results indicated that the magnetic MIPs also have potential applications in controlled drug release. Furthermore, the m‐MIPs were applied to the extraction of carvedilol from human blood plasma samples. Carvedilol can be quantified by this method in the 2–350 μg L^?1 concentration range. The limit of detection and limit of quantification in plasma samples are 0.13 and 0.45 μg L^?1. The results from HPLC showed good precision (3.5% for 50.0 μg L^?1) and recoveries (between 85 and 93) using m‐MIP from human plasma samples. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41209.     

HYDROCARBON LOADS FROM STREET CLEANING PRACTICES: COMPARISON WITH DRY AND WET WEATHER FLOWS IN A PARISIAN COMBINED SEWER SYSTEM

Abstract

So far, little attention has been given to the effect of the street cleaning waters (SCW) load on the sewer systems during dry-weather periods. However, the knowledge of this pollution is needed to better understand the contribution of SCW to dry weather flow (DWF) pollution within combined sewers. Therefore, hydrocarbon loads conveyed by SCW were analyzed for two different sites of the Paris agglomeration. Median n-alkane, Unresolved Complex Mixture (UCM) and Polycyclic Aromatic Hydrocarbon (PAH) concentrations have been estimated at 19, 628 and 1.4 μ g · l^{? 1}for the Marais catchment (or 4th district), and at 8, 249, and 2.1 μ g · l^{? 1}for the 13th district, respectively. The observed contamination was mainly attributed to road traffic. Moreover, a comparison between SCW and street runoff showed that street cleaning removes a higher PAH stock than street runoff. In addition, SCW hydrocarbon fluxes evaluated at 5.4, 178 and 0.4 g · d^{? 1}for n-alkanes, UCM and PAH, respectively, were compared to the hydrocarbon fluxes of the DWF pollutant load at the combined sewer outlet of the Marais catchment. Hydrocarbon loads conveyed by SCW into Paris combined sewers appeared to be a minor source of DWF pollution for n-alkane and UCM, but represented a significant source for PAHs.     

Fermentative production of L(+)‐lactic acid from starch hydrolyzate and corn steep liquor as inexpensive nutrients by batch culture of Enterococcus faecalis RKY1

BACKGROUND: Attempts were made to determine the lactic acid production efficiency of novel isolate, Enterococcus faecalis RKY1 using four different starches (corn, tapioca, potato, and wheat starch) with different concentrations (50, 75, 100, and 125 g L^?1) and corn steep liquor as an inexpensive nitrogen source. RESULTS: The yield of lactic acid from each starch was higher than 95% based on initial starch concentrations. High lactic acid concentration (129.9 g L^?1) and yield (1.04 g‐lactic acid g^?1‐starch) were achieved faster (84 h) from 125 g L^?1 of corn starch. Among the starches used, tapioca starch fermentation usually completed in a shorter incubation period. The final dry cell weight was highest (7.0 g L^?1) for the medium containing 75 g L^?1 of corn starch, which resulted in maximum volumetric productivity of lactic acid (3.6 g L^?1 h^?1). The addition of 30 g L^?1 corn steep liquor supplemented with a minimal amount of yeast extract supported both cell growth and lactic acid fermentation. CONCLUSION: Enterococcus faecalis RKY1 was found to be capable of growing well on inexpensive nutrients and producing maximum lactic acid from starches and corn steep liquor as lower‐cost raw materials than conventionally‐used refined sugars such as glucose, and yeast extract as an organic nitrogen source in laboratory‐scale studies. These fermentation characteristics are prerequisites for the industrial scale production of lactic acid. Copyright © 2008 Society of Chemical Industry     

The Use of Copper Immobilized on Silica for Compound Class Fractionation of Polycyclic Aromatic Compounds in Environmental Samples

Abstract

Copper immobilized on silica has been investigated as an adsorbent for the fractionation of polycyclic aromatic compounds (PACs) into different compound classes. an open column chromatographic packing based on copper (II) bound to a silica substrate was used as a means of subdividing the PACs into less complex groups of similar compound types. the process has been applied to the fractionation of PACs extracted from a marine harbour sediment, for which the complex mixture of PACs could be separated into three subgroups, the contents of which were: (1) polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, and thiophenes; (2) compounds containing pyrrole-type (sp ³-hybridized) nitrogen (carbazoles), and also quinones and other oxygen containing species; and (3) compounds containing pyridine-type(sp ²-hybridized) nitrogen (acridine and its homologues). the fractions thus obtained have been characterized by gas chromatography-mass spectrometry (GC-MS). Extracted mass spectra, obtained from the crests of GC-MS peaks observed in reconstructed single ion chromatograms of selected m/z values, enabled unambiguous identification of many of the minor components of the mixture.     

Microfunnel magnetic stirring-assisted dispersive liquid–liquid microextraction-derivatization technique,for the determination of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (Mutagen X) in aqueous samples by GC-ECD

A simple, highly sensitive and reliable microfunnel magnetic stirring-assisted dispersive liquid–liquid microextraction method (MF-MSA-DLLME) was developed based on the derivatization of mutagen X in aqueous samples and determined using gas chromatography with electron capture (GC-ECD). The effects of different variables on the extraction efficiency were investigated and optimized. The calibration curve showed good linearity in the concentration range of 0.05–400 μgL^?1 (r² = 0.998) and precision (RSD = 5.0%). Under optimum conditions, the limit of detection (LOD) and the limit of quantification in drinking water were 0.015 and 0.05 µg L^?1, respectively. The developed method was successfully applied for the determination of six Mutagen X (MX) in real samples.     

Production and Quantitative Analysis of Trehalose Lipid Biosurfactants Using High‐Performance Liquid Chromatography

Trehalose lipids (THL) are glycolipid biosurfactants having a wide range of biomedical and environmental applications. Low yield, high purification cost, and the absence of a valid analytical method hinders their application. Hence, in the present study a simple, rapid, and reliable isocratic high‐performance liquid chromatography (LC) method was developed for the identification and quantification of trehalose lipid biosurfactants from Rhodococcus erythropolis. THL having a minimum surface tension of 24 mN m^?1 and a critical micellar concentration of 25 mg L^?1 were produced using hexadecane as a substrate. A standard was developed from the crude THL mixture using thin‐layer chromatography and column chromatography and its structure was confirmed using infrared spectroscopy, mass spectroscopy, and ¹H NMR. A high performance liquid chromatography (HPLC) method for quantitation was developed using a C18 column with water/acetonitrile (80:20) as the mobile phase at a 1 mL min^?1 flow rate and UV detection at 208 nm. This method was validated according to International Conference on Harmonization guidelines for linearity, precision, accuracy, robustness, LOD, and LOQ. This method was found to be linear over the range 10‐50 μg m L^?1 (r² =0.99801), precise, accurate, and robust. This method can detect minimum 3.2 μg mL^?1 and quantify minimum 9.2 μg mL^?1 of THL. Standards were developed from R. erythropolis, broth and purified standard trehalose 6,6′‐dimycolate from Mycobacterium bovis, having the same retention time of 2.0 min. The yield was calculated from the calibration curve and was found to be 25 g L^?1.     

Zinc ion-imprinted polymer based on silica particles modified carbon paste electrodes for highly selective electrochemical determination of zinc ions

ABSTRACT

In this study, Zn(II) ion-imprinted polymer was prepared on the surface of vinyl silica particles and applied for detection of Zn(II) ions using differential pulse voltametry. The ion- imprinted polymer particles were prepared by free radical polymerization. The prepared particles were characterized by different morphological and elemental techniques. The ion-imprinted particles were used to fabricate the carbon paste electrode as a zinc ions sensor. The modified zinc sensor showed linear response in the concentration range 6.12 × 10^?9 to 4.59 × 10^?8 mol L^?1. The limit of detection and limit of quantification of the electrode were 1.351 × 10^?8 and 4.094 × 10^?8 mol L^?1, respectively.     

Bio‐oxidation of ferrous ions by Acidithioobacillus ferrooxidans in a monolithic bioreactor

BACKGROUND: The bio‐oxidation of ferrous iron is a potential industrial process in the regeneration of ferric iron and the removal of H₂S in combustible gases. Bio‐oxidation of ferrous iron may be an alternative method of producing ferric sulfate, which is a reagent used for removal of H₂S from biogas, tail gas and in the pulp and paper industry. For practical use of this process, this study evaluated the optimal pH and initial ferric concentration. pH control looks like a key factor as it acts both on growth rate and on solubility of materials in the system. RESULTS: Process variables such as pH and amount of initial ferrous ions on oxidation by A. ferrooxidans and the effects of process variables dilution rate, initial concentrations of ferrous on oxidation of ferrous sulfate in the packed bed bioreactor were investigated. The optimum range of pH for the maximum growth of cells and effective bio‐oxidation of ferrous sulfate varied from 1.4 to 1.8. The maximum bio‐oxidation rate achieved was 0.3 g L^?1 h^?1 in a culture initially containing 19.5 g L^?1 Fe²⁺ in the batch system. A maximum Fe²⁺ oxidation rate of 6.7 g L^?1 h^?1 was achieved at the dilution rate of 2 h^?1, while no obvious precipitate was detected in the bioreactor. All experiments were carried out in shake flasks at 30 °C. CONCLUSION: The monolithic particles investigated in this study were found to be very suitable material for A. ferrooxidans immobilization for ferrous oxidation mainly because of its advantages over other commonly used substrates. In the monolithic bioreactor, the bio‐oxidation rate was 6.7 g L^?1 h^?1 and 7 g L^?1 h^?1 for 3.5 g L^?1 and 6 g L^?1 of initial ferrous concentration, respectively. For higher initial concentrations 16 g L^?1 and 21.3 g L^?1, bio‐oxidation rate were 0.9 g L^?1 h^?1 and 0.55 g L^?1 h^?1, respectively. Copyright © 2008 Society of Chemical Industry     

Conversion efficiency of glucose/xylose mixtures for ethanol production using Saccharomyces cerevisiae ITV01 and Pichia stipitis NRRL Y‐7124

BACKGROUND: Efficient conversion of glucose/xylose mixtures from lignocellulose is necessary for commercially viable ethanol production. Oxygen and carbon sources are of paramount importance for ethanol yield. The aim of this work was to evaluate different glucose/xylose mixtures for ethanol production using S. cerevisiae ITV‐01 (wild type yeast) and P. stipitis NRRL Y‐7124 and the effect of supplying oxygen in separate and co‐culture processes. RESULTS: The complete conversion of a glucose/xylose mixture (75/30 g L^?1) was obtained using P. stipitis NRRL Y‐7124 under aerobic conditions (0.6 vvm), the highest yield production being Y_p/s = 0.46 g g^?1, volumetric ethanol productivity Q_pmax = 0.24 g L^?1 h^?1 and maximum ethanol concentration P_max = 34.5 g L^?1. In the co‐culture process and under aerobic conditions, incomplete conversion of glucose/xylose mixture was observed (20.4% residual xylose), with a maximum ethanol production of 30.3 g L^?1, ethanol yield of 0.4 g g^?1 and Q_pmax = 1.26 g L^?1 h^?1. CONCLUSIONS: The oxygen present in the glucose/xylose mixture promotes complete sugar consumption by P. stipitis NRRL Y‐7124 resulting in ethanol production. However, in co‐culture with S. cerevisiae ITV‐01 under aerobic conditions, incomplete fermentation occurs that could be caused by oxygen limitation and ethanol inhibition by P. stipitis NRRL Y‐7124; nevertheless the volumetric ethanol productivity increases fivefold compared with separate culture. Copyright © 2011 Society of Chemical Industry     

Pre‐treatment and utilization of raw glycerol from sunflower oil biodiesel for growth and 1,3‐propanediol production by Clostridium butyricum

BACKGROUND: The objective of the present work is to report an efficient pre‐treatment process for sunflower oil biodiesel raw glycerol (SOB‐RG) and its fermentation to 1,3‐propanediol. RESULTS: The growth inhibition percentages of Clostridium butyricum DSM 5431 on grade A (pH 4.0) and grade B (pH 5.0) phosphoric acid‐treated SOB‐RG were similar to those of pure glycerol at 20 g glycerol L^?1; i.e., 18.5 ± 0.707% to 20.5 ± 0.7% inhibition. In grade A, growth inhibition was reduced from 85.25 ± 0.35% to 32 ± 1.4% (a 53.25% reduction) at 40 g glycerol L^?1 by washing grade A raw glycerol twice with n‐hexanol (grade A‐2). The kinetic parameters for product formation and substrate consumption in anaerobic batch cultures gave almost similar values at 20 g glycerol L^?1, while at 50 g glycerol L^?1 volumetric productivity (Q_p) and specific rate of 1,3‐propanediol formation (q_p) were improved from 1.13 to 1.85 g L^?1 h^?1 and 1.60 to 2.65 g g^?1 h^?1, respectively, by employing grade A‐2 raw glycerol, while the yields were similar (0.5–0.52 g g^?1). CONCLUSION: The results are important as the pre‐treatment of SOB‐RG is necessary to develop bioprocess technologies for conversion of SOB‐RG to 1,3‐propanediol. Copyright © 2008 Society of Chemical Industry     

INTERACTION OF HYDROXYLATED POLYCYCLIC AROMATIC HYDROCARBONS TO ESTROGEN RECEPTOR

Binding activities and estrogenic/antiestrogenic activities of polycyclic aromatic hydrocarbons (PAHs) and hydroxylated PAHs (OHPAHs) having 2 to 6 rings were evaluated by competition assay and yeast two-hybrid assay expressing human estrogen receptor (hER), respectively. PAHs did not bind to hER and did not show any activity. On the other hand, OHPAHs bound to hER and several OHPAHs showed estrogenic or antiestrogenic activity. Relative estrogenic activity (REP _E ) and antiestrogenic activity (REP _AE ) were calculated from the values of E ₂ and 4-hydroxytamoxyfen as positive controls, respectively. Several OHPAHs having 4 rings showed strongly estrogenic activity. 4-Hydroxybenzo[a]anthracene exhibited the strongest estrogenic activity (REP _E = 7.5 × 10^?3 ) followed by 3-hydroxybenzo[a]anthracene and 2-hydroxychrysene (REP _E = 4.2 × 10^?3 ). Several other 4-ring OHPAHs showed strongly antiestrogenic activity. 3-Hydroxybenzo[c]phenanthrene exhibited the strongest antiestrogenic activity (REP _AE = 190) followed by 2-hydroxybenzo[c]phenanthrene (REP _AE = 69) and 2- hydroxybenz [a]anthracene (REP _AE = 0.42). The results suggested that there is a strong structure – activity relationship.