Abstract  Mechanistic investigation of the oxidative degradation of d-fructose (D-Fruc) has been studied by spectrophotometric technique. Molecular mechanics (MM +) calculations suggest that the potential energy (PE/kcal mol-1) of the d-fruc (opening structure) is at least three (3.71) times more stable than the PE of the cycling structure of the same matrix. The oxidation constant (Kox) of the anionic form of the d-Fruc (Fruc-NaOH) is about seven times greater than that of the protonated form (Fruc-H2SO4). Therefore, the anionic form is more highly oxidizable than is the cationic form of this matrix. The limit of detection can be as low as 18 ppm (mg L-1) of d-Fruc. This is about 60 times lower than the blood sugar level (BSL) or 100 times lower than that reported previously. The proposed procedure was applied successfully for the oxidation of D-Fruc in uni-fructose powder. The anionic form of D-Fruc (Fruc-NaOH) has the ability to store energy about 744.72 kJ g-1 h at 608 nm in a condensed lightweight form. Kinetic parameters of the oxidative degradation of the anionic form of D-Fruc at different concentration were deduced. A number of models were used to evaluate the kinetic parameters. The mechanism of the degradation of D-Fruc is explained on the basis of kinetic parameters. [ABSTRACT FROM AUTHOR] Copyright of Spectroscopy Letters is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts)

Abstract  Ion channels from the midgut apical membrane of gypsy moth (Lymantria dispar) larvae were studied following mechanical fusion of brush-border membrane vesicles with planar phospholipid bilayer membranes. In symmetrical 300 mmol l(-)(1) KCl (pH 9.0), nine different channels with conductances ranging from 27 to 795 pS and linear current/voltage relationships were resolved. In the presence of a KCl gradient across the bilayer (450 mmol l(-)(1 )cis/150 mmol l(-)(1 )trans), 11 different conductance levels ranging from 16 to 850 pS were detected. The channels were slightly cationic: the zero-current reversal potential was shifted by -5 mV to -21 mV compared with symmetrical KCl conditions, corresponding to p(K)/p(Cl) permeability ratios of 1.5-8.0. Most channels were neither voltage-dependent nor Ca(2+)-sensitive and displayed complex gating kinetics. Addition of Ba(2+) or Cs(+) to both sides of the bilayer had little effect on channel activity, but fewer distinct channels were observed when KCl was replaced by potassium gluconate, suggesting an effect of Cl(-) on channel activity. A reduced number of channels was also detected when KCl was replaced by N-methyl- d-glucamine-HCl. Under asymmetrical N-methyl-d-glucamine-HCl conditions, only anionic channels were observed. They exhibited current rectification (35 pS at negative voltages and 81 pS at positive voltages) and were strongly voltage-dependent.

Abstract  The mineral phosphate-solubilizing (MPS) activity of a Pantoea agglomerans strain, namely MMB051, isolated from an iron-rich, acidic soil near Ciudad Piar (Bolívar State, Venezuela), was characterized on a chemically defined medium (NBRIP). Various insoluble inorganic phosphates, including tri-calcium phosphate [Ca(3)(PO(4))(2)], iron phosphate (FePO(4)), aluminum phosphate (AlPO(4)), and Rock Phosphate (RP) were tested as sole sources of P for bacterial growth. Solubilization of Ca(3)(PO(4))(2) was very efficient and depended on acidification of the external milieu when MMB051 cells were grown in the presence of glucose. This was also the case when RP was used as the sole P source. On the other hand, the solubilization efficiency toward more insoluble mineral phosphates (FePO(4) and AlPO(4)) was shown to be very low. Even though gluconic acid (GA) was detected on culture supernatants of strain MMB051, a consequence of the direct oxidation pathway of glucose, inorganic-P solubilization seemed also to be related to other processes dependent on active cell growth. Among these, proton release by ammonium (NH(4)(+) ) fixation appeared to be of paramount importance to explain inorganic-P solubilization mediated by strain MMB051. On the contrary, the presence of nitrate (NO(3)(-) ) salts as the sole N source affected negatively the ability of MMB051 cells to solubilize inorganic P.

Abstract  The influence of polysaccharide annealing temperature on interactions in acid-induced sodium caseinate (CAS), -carrageenan (CAR), and sucrose gels were studied. Gels were formed by glucone--lactone (GDL) addition to mixed systems leading to a slow acidification towards the protein isoelectric point. The system properties were a result of phase separation between the biopolymers, simultaneously with gelation, resulting in a heterogeneous network with particulate structure. The results showed that gels with an increased whiteness index and water entrapped were obtained at higher caseinate concentration. Increasing caseinate and carrageenan concentration resulted in more brittle and elastic gels, whereas stress in rupture behaviour depended on the relative concentration of biopolymers. The depletion-flocculation phenomenon became evident at higher biopolymer concentration, resulting in network weakening and lower water release, although this effect was reduced with sucrose addition.

Abstract  An acid Cu-Sn deposition bath was developed, and copper and copper-tin coatings were electrodeposited on polycrystalline platinum. The effect of gelatin on copper and copper-tin electrodeposition from acid sulfate solutions has been investigated by a variety of electrochemical methods (voltammetric studies and electrochemical quartz crystal microbalance) as well as by morphologic technique (scanning electron microscopy). The electrochemical results have shown that the overpotential is required when gelatin is added, indicating the presence of interaction between the additive and the coating. From the results of X-ray photoelectron spectroscopy, PM-IRRAS and cyclic voltammetry, gelatin was found to react with metal ions and platinum substrate. Adsorption of gelatin on the coating and platinum substrate is shown. Gelatin adsorption seemed to inhibit the initial nucleation of the copper and copper-tin electrodeposition, allowing homogeneous and smaller crystallites. Addition of gelatin was found to have an effect on reducing copper-tin alloys. The presence of gelatin impacts the crystal size and morphology of Cu-Sn deposits. (C) 2014 Elsevier B.V. All rights reserved.

Abstract  Pseudomonas putida morphine dehydrogenase is shown to be closely homologous to 18 proteins, defining a superfamily within which morphine dehydrogenase particularly resembles two bacterial, 2,5-dioxo-D-gluconic acid reductases, and two eukaryotic proteins of unknown functions. Relationships within the superfamily are extensive and complex. Residue identities between protein pairs range from 29-90%. Three subgroups are proposed. Nevertheless, on the basis of residue conservations/exchanges it is suggested that the nicotinamide coenzyme binding and substrate reduction occur in all the enzymes by broadly analogous mechanisms, among which some probable differences are identified.

Abstract  The aim of this study was to investigate the role of process conditions and system composition on the acid-induced gelation of a mixture of milk protein and gum tragacanth. This was studied by determining the effects of co-solute (lactose) addition (3, 5 and 7%) and gelation temperature (25, 37 and 45°C) on the mixture's rheological properties and microstructure using a combination of techniques including small-deformation rheology and scanning electron microscopy. The presence of lactose played an important role in the microstructure formation of gels but did not change most rheological properties. The microstructure of gels formed in the presence of lactose was coarser and more particulate, but less interconnected; this can be explained by lactose's role in improving protein aggregation. Gels prepared at a lower temperature had a high structure strength, as indicated by their high storage modulus, τ(f) and G(f) values. Low gelation temperature also caused a more branched and homogenous microstructure.

Abstract  We discuss the stability of bubbles to coalescence when undergoing a pressure drop and their stability to disproportionation under quiescent conditions, studied using previously established 'single bubble layer experimental' techniques, focussing on the effects on stability of the inclusion of a low volume fraction (0.25%) of stable oil droplets. Detailed measurements of the surface dilatational elasticity (epsilon(s)) and surface shear viscosity (eta(s)) of systems in the presence and absence of oil droplets have been performed. The Surface rheology and stability have been measured as a function of adsorption time and pH, between pH 4.5 and 7, by including glucono-delta-lactone (GDL) as an acidification agent. Commercial sodium caseinate (SC) and purified beta-lactoglobulin (beta-L) were used at 1 wt% bulk concentration as bubble stabilizing agents. The emulsion oil droplet phase was n-tetradecane (TD) or 1-bromohexadecane (BHD), with a mean droplet size of (d(43)) = 0.59 and 0.67 mu m, respectively. The emulsion droplets were completely stable to coalescence and did not enter or spread at the air-water (A-W) interface. With SC at all pH values the values of eta(s) were markedly higher in the presence of TD droplets than in their absence, but particularly when the pH was lowered to pH <= 5.5 such that the SC started to aggregate. The increase in eta(s), correlated with the increase in coalescence stability under the same conditions. With neutrally buoyant BHD droplets the increase in eta(s) was not as great, but eta(s), was still significantly higher than in the absence of droplets, indicating that the rise to, and packing of, TD droplets at the A-W interface due to gravity was not solely responsible for their observed effects. The values of epsilon(s) did not increase much at all for either beta-L or SC as the pH was lowered and/or TD droplets were added, except at very low pH values, when the effects with SC were obscured by the tendency for the bulk SC to gel. In agreement with the relatively insignificant changes in epsilon(s) as the pH was lowered or droplets were added, the resistance to disproportionation of bubbles did not change very much either. (C) 2008 Elsevier Ltd. All rights reserved.

Abstract  An argon glow discharge plasma was used for the reduction of carbon-supported Au catalysts at ambient temperature. The plasma-reduced Au/C sample produced 7-8 nm Au particles that were highly dispersed on carbon. The surface oxygen species on carbon were increased by plasma treatment. Most interestingly, the metal particles were recessed into the carbon substrate. The stronger anchoring enhanced the stability of the active metal loaded on the support. The Au/C catalysts were tested for selective oxidation of glucose to gluconic acid compared with conventional hydrogen reduced catalysts. A significant improvement in glucose oxidation was achieved by the plasma-reduced sample. (C) 2012 Elsevier B.V. All rights reserved.

Abstract  Butyrate has an antitumorigenic effect on colorectal cancer cell lines. Dietary sodium gluconate (GNA) promotes butyrate production in the large intestine. Accordingly, we examined the effect of dietary GNA on tumorigenesis in the large intestine in rats. Male Fisher-344 rats (n = 32) were divided into 4 groups: 2 diets (with or without 50 g GNA/kg basal diet) X 2 treatments (with or without carcinogen administration). Colonic tumors were induced by 3 intraperitoneal injections of azoxymethane (115 mg/kg body wt, 1 time/wk) and dietary deoxycholic acid (2 g/kg basal diet). The experiment was conducted for 33 wk except for a few rats. Ingestion of GNA increased cecal butyrate concentration at the end of experiment (P < 0.01). No tumor development occurred in the untreated groups. Ingestion of GNA decreased the incidence of tumors in rats administered the carcinogen (37.5 vs. 100%, P < 0.05). Ingestion of GNA also decreased the mean number of tumors per rat (0.5 +/- 0.8 vs. 2.8 +/- 1.5, P < 0.01). beta-Catenin accumulation and TdT-mediated dUTP nick end labeling (TUNEL) positive cells in tumors were histochemically examined. The results of this study suggested that the antitumorigenic effect of GNA may involve the stimulation of apoptosis through enhanced butyrate production in the large intestine.

Abstract  Biomasses of methylotrophic bacteria, yielded by biotechnological processes as waste products, can represent a source of ubiquinones, especially of the ubiquinone-10. Possibilities for the separation of ubiquinones were studied on waste biomasses from the microbial production of gluconic acid, from the production of intracellular poly-beta-hydroxybutyric acid (PHB) and from the sewage treatment. The ubiquinones are extracted with supercritical CO2 in the presence of methanol or ethanol as entrainer. The separation of ubiquinones with supercritical extraction was more effective than with conventional extraction methods. The advantages are especially the low extract quantities and the high ubiquinone content in the extracts. The crude ubiquinones can be purified by using the preparative HPLC technique.

Abstract  Membrane-integrated quinoprotein glucose dehydrogenase from Acinetobacter calcoaceticus was produced by heterologous expression of the gene for it in an Escherichia coli recombinant strain. The apoenzyme (lacking the cofactor pyrroloquinoline quinone, PQQ) was solubilized with Triton X-100 and purified to homogeneity. Reconstitution of the apoenzyme to full activity in the assay was achieved with a stoichiometric amount of PQQ in the presence of Mg2+. Just as for other PQQ-containing dehydrogenases where Ca2+ fulfills this role, Mg2+ anchors PQQ to the mGDH protein and activates the bound cofactor. This occurs in a precise way since high anomer specificity was found for the enzyme toward the sugars tested. Although the steady-state-type kinetics were as expected for a dye-linked dehydrogenase (ping-pong) and the PQQ in it was present in oxidized form, addition of glucose to the holoenzyme resulted in a very slow but continuous production of gluconolactone; i.e., the reaction did not stop after one turnover, with O2 apparently acting as an (albeit poor) electron acceptor by reoxidizing PQQH2 in the enzyme. The surprisingly low reactivity with glucose, in the absence of dye, as compared to the activity observed in the steady-state assay appeared to be due to formation of an anomalous enzyme form, mGDH. Formation of normal holoenzyme, mGDH, reducing added glucose immediately to gluconolactone (in one turnover), was achieved by treating mGDH with sulfite, by reconstituting apoenzyme with PQQ in the presence of sulfite, or by applying assay conditions to mGDH (addition of PMS/DCPIP). As compared to other quinoprotein dehydrogenases, mGDH appears to be unique with respect to the mode of PQQ-binding, as expressed by the special conditions for reconstitution and the absorption spectra of the bound cofactor, and the reactivity of the reduced enzyme toward O2. The primary cause for this seems not to be related to a different preference for the activating bivalent metal ion but to the special way of binding of PQQ to mGDH.

Abstract  The regulation of PTH secretion by calcium is altered in patients with primary hyperparathyroidism. A similar disturbance may occur in secondary hyperparathyroidism, but direct in vivo comparisons of PTH secretion in normal subjects and those with secondary hyperparathyroidism have not been made. Thus, 13 patients with end-stage renal failure and secondary hyperparathyroidism and 20 healthy volunteers underwent dynamic tests of PTH secretion. Changes in ionized calcium were induced by 2-h iv infusions of calcium gluconate or sodium citrate on consecutive days, and the sigmoidal relationship between serum ionized calcium and PTH levels was examined. During sodium citrate infusions, serum ionized calcium levels decreased by 0.21 +/- 0.04 and 0.20 +/- 0.05 mmol/L, respectively (mean +/- SD), in normal volunteers and dialyzed patients (P = NS). Serum PTH levels rose from 27 +/- 7 to 107 +/- 33 pg/mL in controls and from 480 +/- 238 to 859 +/- 412 pg/mL in dialyzed subjects; thus, maximum PTH levels were 396% of preinfusion values in normal subjects, but only 79% greater than baseline values in dialyzed patients (P < 0.001). During the first 30 min of calcium infusions, the increase in serum ionized calcium did not differ between groups, but PTH levels fell more rapidly in normal volunteers; values were 24% of preinfusion levels in controls, but only 56% of the baseline in dialyzed patients (P < 0.01) after 30 min. Minimum PTH levels were attained after 50 min of calcium infusion in normal volunteers and after 70 min in dialyzed patients. The derived values for set-point were 1.21 +/- 0.04 and 1.24 +/- 0.06 mmol/L, respectively, in control and dialyzed subjects (P = NS). These results do not support the contention that the set-point for calcium-regulated PTH secretion is greater than normal in patients with secondary hyperparathyroidism due to end-stage renal disease.

Abstract  BACKGROUND: Patients' exposure to and potential toxicity from aluminum in parenteral nutrition (PN) formulations is an important concern of healthcare providers.

OBJECTIVE: To determine the potential for aluminum toxicity caused by PN in hospitalized adults who have risk factors of both acute kidney injury and PN.

METHODS: Adults who required PN and had a serum creatinine (SCr) level at least 1.5 times greater than the admission SCr on the first day of PN were studied in a retrospective fashion. Protein was administered based on whether hemodialysis was being used (0.6-1 g/kg/day without hemodialysis; 1.2-1.5 g/kg/day with hemodialysis). Aluminum exposure was determined for each patient by multiplying the volume of each PN component by its concentration of aluminum. Unpaired t-tests, Fisher's exact test, and analysis of variance were used for statistical analysis. Data are presented as mean +/- SD.

RESULTS: Thirty-six patients (aged 50.4 +/- 20.4 y; weight 90.2 +/- 32.8 kg) were studied. Initial serum urea nitrogen and SCr were 47 +/- 23 and 3.3 +/- 1.4 mg/dL, respectively. Twelve patients received hemodialysis. The mean aluminum exposure was 3.8 +/- 2 microg/kg/day in the 36 patients. Of these, 29 had safe calculated aluminum exposure (<5 microg/kg/day) and 7 had high calculated aluminum exposure (>5 microg/kg/day). Patients with safe aluminum exposure had significantly higher SCr levels than did those with high aluminum exposure (3.5 +/- 1.5 vs 2.2 +/- 0.7 mg/dL; p < 0.04). Patients with high aluminum exposure received significantly more aluminum from calcium gluconate compared with those who had safe aluminum exposure (357 +/- 182 vs 250 +/- 56 microg/day; p < 0.02). Limitations of the study include its retrospective design, which resulted in calculated versus direct measurement of aluminum.

CONCLUSIONS: Using our calculations, we believe that most patients with acute kidney injury who require PN do not receive excessive exposure to aluminum from the PN formulation, despite having 2 risk factors (acute kidney injury, PN) for aluminum toxicity.

Abstract  AIMS: The purpose of this work was to study the involvement of micro-organisms, which develop together with Botrytis cinerea on grapes, in the SO2 binding power of musts.

METHODS AND RESULTS: Yeasts and bacteria were involved. Most bacteria were acetic acid bacteria, mainly of the Gluconobacter genus. Unlike oxidative yeasts, Gluconobacter produce gluconic acid (in balance with delta-gluconolactone) from glucose, 5-oxofructose from fructose and dihydroxyacetone from glycerol. Production of carbonyl compounds from other sugars and polyols was not detected or was very weak.

CONCLUSION: Acetic acid bacteria are responsible for the increases in SO2 binding power of musts from botrytized grapes by oxidizing the three main sugars of these grapes.

SIGNIFICANCE AND IMPACT OF THE STUDY: Up to 80% of the SO2 binds with products of Gluconobacter which easily grow on 'botrytized' grapes. Depending on climatic conditions, some vintages are particularly difficult to stabilize.

Abstract  Hazmat emergency preparedness is critical, especially as Hong Kong prepares for major international events, such as the 2008 Olympic Equestrian Games. No published medical study has described the identities and quantities of dangerous goods (DG) in the Kowloon area and listed what antidotes are needed for these DG. This study describes what hazardous materials are most common in Kowloon to prioritise emergency preparedness and training. Materials & methods: Design: A descriptive, cross-sectional study. Setting: The Hong Kong Special Administrative Region, specifically Kowloon. Sample: The Hong Kong Fire Services Department (HKFSD) Dangerous Goods Database (DGD). Interventions: Descriptive statistical analyses with Stata 9.2. Chiefoutcome: Identifying and quantifying dangerous goods in the HKFSD DGD. Results: Most DG do not have antidotes. The most common DG with recognised antidotes are carbon monoxide, methylene chloride, fluorine, fluorides, fluoroboric acid, cyanides, nitriles, methanol, nitrobenzene, nitrites, and nitrates. The most common categories of DG are substances giving off inflammable vapours, compressed gases, and corrosive and poisonous substances. Conclusions: Hazmat emergency preparedness and training should emphasize these most common categories of DG. Disaster planning should ensure adequate antidotes for DG with recognised antidotes, i.e., oxygen for carbon monoxide and methylene chloride; calcium gluconate or calcium chloride for fluorine, fluorides, and fluoroboric acid; hydroxocobalamin for cyanides and nitriles; ethanol for methanol; and methylene blue for methaemoglobinaemia produced by nitrobenzene, nitrites, and nitrates. Supportive care is essential for patients exposed to hazardous materials because most dangerous goods do not have antidotes.

Abstract  This study used batch reactors to characterize the mechanisms and rates of elemental release (Al, Ca, K, Mg, Na, F, Fe, P, Sr, and Si) during interaction of a single bacterial species (Burkholderia fungorum) with granite at T = 28 degrees C for 35 days. The objective was to evaluate how actively metabolizing heterotrophic bacteria might influence granite weathering on the continents. We supplied glucose as a C source, either NH4 or NO3 as N sources, and either dissolved PO4 or trace apatite in granite as P sources. Cell growth occurred under all experimental conditions. However, solution pH decreased from similar to 7 to 4 in NH4-bearing reactors, whereas pH remained near-neutral in NO3-bearing reactors. Measurements of dissolved CO2 and gluconate together with mass-balances for cell growth suggest that pH lowering in NH4-bearing reactors resulted from gluconic acid release and H+ extrusion during NH4 uptake. In NO3-bearing reactors, B. fungormum likely produced gluconic acid and consumed H+ simultaneously during NO3 utilization. Over the entire 35-day period, NH4-bearing biotic reactors yielded the highest release rates for all elements considered. However, chemical analyses of biomass show that bacteria scavenged Na, P, and Sr during growth. Abiotic control reactors followed different reaction paths and experienced much lower elemental release rates compared to biotic reactors. Because release rates inversely correlate with pH, we conclude that proton-promoted dissolution was the dominant reaction mechanism. Solute speciation modeling indicates that formation of Al-F and Fe-F complexes in biotic reactors may have enhanced mineral solubilities and release rates by lowering Al and Fe activities. Mass-balances further reveal that Ca-bearing trace phases (calcite, fluorite, and fluorapatite) provided most of the dissolved Ca, whereas more abundant phases (plagioclase) contributed negligible amounts. Our findings imply that during the incipient stages of granite weathering, heterotrophic bacteria utilizing glucose and NH4 only moderately elevate silicate weathering reactions that consume atmospheric CO2. However, by enhancing the dissolution of non-silicate, Ca-bearing trace minerals, they could contribute to high Ca/Na ratios commonly observed in granitic watersheds. (c) 2007 Elsevier Ltd. All rights reserved.

Abstract  In this study, an attempt was made to identify an effective phosphate solubilizing bacteria from pesticide polluted field soil. Based on the formation of solubilization halo on Pikovskaya's agar, six isolates were selected and screened for pesticide tolerance and phosphate (P) solubilization ability through liquid assay. The results showed that only one strain (SGRAJ09) obtained from Achillea clavennae was found to tolerate maximum level of the pesticides tested and it was phylogenetically identified as Pseudomonas sp. It possessed a wide range of pesticide tolerance, ranging from 117 μg mL(-1) for alphamethrin to 2,600 μg mL(-1) for endosulfan. The available P concentrations increased with the maximum and double the maximum dose of monocrotophos and imidacloprid, respectively. On subjected to FT-IR and HPLC analysis, the presence of organic acids functional group in the culture broth and the production of gluconic acid as dominant acid aiding the P solubilization were identified. On comparison with control broth, monocrotophos and imidacloprid added culture broth showed quantitatively high organic acids production. In addition to gluconic acid production, citric and acetic acids were also observed in the pesticide amended broth. Furthermore, the Pseudomonas sp. strain SGRAJ09 possessed all the plant growth promoting traits tested. In presence of monocrotophos and imidacloprid, its plant growth promoting activities were lower than that of the pesticides unamended treatment.

Abstract  Titania-supported gold nanoparticles were prepared by using the deposition-precipitation method, followed by reduction under a hydrogen flow. The catalytic activity of these as-prepared catalysts was explored in the oxidation of cellobiose to gluconic acid with molecular oxygen, and the properties of these catalysts were examined by using XRD, TEM, temperature-programmed desorption of NH3, energy-dispersive X-ray spectroscopy, UV/Vis, and X-ray photoemission spectroscopy (XPS). The catalyst sample reduced at high temperature demonstrated an excellent catalytic activity in the oxidation of cellobiose. The characterization results revealed the strong metal-support interaction between the gold nanoparticles and titania support. Hydrogen reduction at higher temperatures (usually >600 degrees C) plays a vital role in affording a unique interface between gold nanoparticles and titania support surfaces, which thus improves the catalytic activity of gold/titania by fine-tuning both the electronic and structural properties of the gold nanoparticles and titania support.

Abstract  The formation of volatile compounds in fresh cheese by 10 Enterobacteriaceae strains of dairy origin (4 Hafnia alvei, 2 Serratia liquefaciens, 1 Enterobacter cloacae, 1 Enterobacter sakazakii, and 2 Escherichia coli strains) was investigated. Small cheeses were made from pasteurized cow's milk separately inoculated with 1-3 x 10(3) CFU/ml of each of the Enterobacteriaceae strains, with glucono-8-lactone added to achieve a pH value of 5.2 in the curds. All strains reached counts close to 10(8) CFU/g in 1-day-old cheeses and survived well from day 1 to day 8. Cheeses were analyzed for volatile compounds by gas chromatography-mass spectroscopy, after extraction by dynamic headspace using a purge and trap apparatus. Sixty-one volatile compounds were determined in cheeses, 31 of which were further investigated. Significant increases of aldehydes, sulfur compounds, and aromatic compounds were recorded from 2-h curd to 1-day-old cheese, and of ketones, alcohols, and acids from 2-h curd to 8-day-old cheese. Acetaldehyde, 2-methyl propanal, and 3-methyl butanal predominated among aldehydes; 2,3-butanedione, 2,3-pentanedione, and 3-hydroxy 2-butanone among ketones; ethanol, 2-methyl propanol, and 3-methyl butanol among alcohols; and ethyl acetate among esters. Hierarchical cluster analysis of strains using the data of 31 volatile compounds separated clearly the strain of E. sakazakii, which produced high amounts of volatile compounds, from the other Enterobacteriaceae strains.

Abstract  The present work consisted in the study of the oxidation Yield induced by catalysts during ozonation of sodium gluconate, toluene sulfonic acid and Triton X100 in dilute aqueous solution (TOC = 8 mg C/L). Two operating conditions have been used to demonstrate the enhancement brought about by catalytic ozonation: continuous filtration experiments and batch tests.

Dynamic filtration experiments have been performed on catalysts previously saturated to simulate the behavior of the catalyst over a long period of use.

Batch experiments which allowed us to distinguish the part due to adsorption, ozonation and catalytic effect were carried out on three catalysts with intent to test their efficiency. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.

Abstract  AIMS: To study phosphate solubilization in Penicillium purpurogenum as function of medium pH, and carbon and nitrogen concentrations.

METHODS AND RESULTS: Tricalcium phosphate (CP) solubilization efficiency of P. purpurogenum was evaluated at acid or alkaline pH using different C and N sources. Glucose- and (NH(4) )(2) SO(4) -based media showed the highest P solubilization values followed by fructose. P. purpurogenum solubilizing ability was higher in cultures grown at pH 6·5 than cultures at pH 8·5. Organic acids were detected in both alkaline and neutral media, but the relative percentages of each organic acid differed. Highest P release coincided with the highest organic acids production peak, especially gluconic acid. When P. purpurogenum grew in alkaline media, the nature and concentration of organic acids changed at different N and C concentrations. A factorial categorical experimental design showed that the highest P-solubilizing activity, coinciding with the highest organic acid production, corresponded to the highest C concentration and lowest N concentration.

CONCLUSIONS: The results described in the present study show that medium pH and carbon and nitrogen concentrations modulate the P solubilization efficiency of P. purpurogenum through the production of organic acids and particularly that of gluconic acid. In the P solubilization optimization studies, glucose and (NH(4) )(2) SO(4) as C and N sources allowed a higher solubilization efficiency at high pH.

SIGNIFICANCE AND IMPACT OF THE STUDY: This organism is a potentially proficient soil inoculant, especially in P-poor alkaline soils where other P solubilizers fail to release soluble P. Further work is necessary to elucidate whether these results can be extrapolated to natural soil ecosystems, where different pH values are present. Penicillium purpurogenum could be used to develop a bioprocess for the manufacture of phosphatic fertilizer with phosphate calcium minerals.