articles+ search results

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Transferts de chaleur et de matière. Garnissages, plateaux de contact, Heat and mass transfer. Packings, plates, Réacteurs, Reactors, Anaérobie, Anaerobe, Anaerobio, Bactérie méthanogène, Methanogenic bacteria, Bacteria metanogénica, Biomasse, Biomass, Biomasa, Granulé, Granule, Granulado, Méthanogenèse, Methanogenesis, Metanogénesis, Production hydrogène, Hydrogen production, Prétraitement, Pretreatment, Pretratamiento, Réacteur, Reactor, Transfert masse, Mass transfer, Transferencia masa, pH, anaerobic granules, biohydrogen, continuous operation, fluorescent molecular tags, methanogenic activity, and selection pressure

BACKGROUND: Several pretreatment methods at lab-scale have been developed to inactivate methane-producing and hydrogen-consuming microorganisms. The need to obtain a hydrogen-producing inoculum by a more practical method is still necessary. The objective of this study was to evaluate the adaptation of anaerobic granules to suppress the methanogenic activity for hydrogen production. RESULTS: Preliminary tests in discontinuous operation indicated that methanogenic bacteria were hardly suppressed. The continuous adaptation of the granules, at pH of 4.5 and HRT of 5.5 h, produced hydrogen and successfully suppressed the methanogenic activity. An even distribution of β-polysaccharides and cells was observed when the adapted granules were stained with fluorescent molecular tags. The reactor productivity was 71 ± 6 mL-H2 Lreactor―1 h―1 with a yield of 2.6 ± 0.2 mol H2 mol-1 glucose. CONCLUSION: Hydrogen was produced from methanogenic granules. The continuous strategy successfully suppressed the methanogenic activity of the seeded granules and the hydrogen production was stable. The high yield and even distribution of cells suggests that the continuous adaptation generated a more active biomass due to an improved mass transfer present in the process.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Fabrication, Manufacturing, Fabricación, bioprocessing, regenerative medicine, and stem cells

Stem cell-derived products have the potential to represent promising therapeutic approaches for the treatment of a wide range of conditions. Neurodegenerative diseases, like Parkinson's disease or Huntington's disease, neurological disorders, cardiac failure, and blood disorders, among others, may one day be treated using cellular therapies and regenerative medicine approaches based on stem cells. Furthermore, owing to the potential positive impact in healthcare systems, translation of stem cell technologies into clinical applications will bring a broad social and economic advantage worldwide. However, to fully realize this potential, advanced bioprocessing systems are needed to deliver sufficient numbers of cells in compliance with stringent regulatory landscapes and that can be used in a safe and effective manner. This review presents and summarizes recent advancements in the field of stem cell engineering, in particular novel technologies for the interrogation of stem cell fate and systems for the robust manufacturing of cells under standardized, reproducible and strictly controlled conditions.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Analyse tendance, Trend analysis, Análisis tendencia, Biomasse, Biomass, Biomasa, Dioxyde de carbone, Carbon dioxide, Carbono dióxido, Disponibilité, Availability, Disponibilidad, Dissolution, Disolución, Eutectique, Eutectic, Eutéctico, Liquide ionique, Ionic liquid, Líquido iónico, Prétraitement, Pretreatment, Pretratamiento, Valorisation, Upgrading, Valorización, Antisolvant, bio-based, ionic liquids, lignocellulose, pretreatment, and switchable

Recent years have witnessed the use of different ionic liquids for biomass processing, either at the level of lignocellulose pre-treatment, to fractionate biomass in its main components, separating hemicellulose and lignin from cellulose, or directly in cellulose decrystallization by dissolving it in the ionic liquid and subsequent precipitation by adding anti-solvents. Yet, most of the ILs employed in these strategies (e.g. imidazolium-based solvents) are (still) expensive for such applications, and provide discussable ecological footprints. In an attempt to combine the highly useful generated knowledge with novel neoteric solvents with improved properties, economics, availability and ecology, several new trends have appeared in these areas during recent years. They comprise the use of switchable ILs, based on strong organic bases and CO2, the application of distillable ILs, as well as the use of bio-based and low-cost ILs and deep-eutectic-solvents (DES), e.g. choline chloride-based derivatives. Apart from other emerging uses, for all these solvents some preliminary applications in biomass processing involving pretreatments, cellulose dissolution and other applications have been successfully reported. This Minireview contextualizes these recent trends and discusses them with emphasis on future use of them in biorefineries and biomass valorization.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Réactions catalytiques, Catalytic reactions, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Réacteurs, Reactors, Agitation mécanique, Stirring, Agitación mecánica, Catalyseur, Catalyst, Catalizador, Cinétique, Kinetics, Cinética, Constante vitesse, Rate constant, Constante velocidad, Optimisation, Optimization, Optimización, Production, Producción, Préparation, Preparation, Preparación, Système biphasique, Biphasic system, Sistema bifásico, Vitesse réaction, Reaction rate, Velocidad reacción, 5-hydroxymethylfurfural, biphasic system, fructose, high-fructose solution addition, and stirring speed

BACKGROUND:5-hydroxymethylfurfural(HMF) has attracted increasing attention so that an efficient process for HMF production from high-sugar solution is needed for the successful commercialization of this versatile intermediate in the production of high value chemicals. RESULTS: Two simple operations, mechanical stirring control and high-fructose solution addition, were applied to the water/butanol system for enhancing fructose-to-HMF reaction using HCl as catalyst. The optimization of stirring speed led to a high HMF yield of 81.7% with 92.0% fructose conversion (0.3 moL L―1 HCl, 1000 rpm). Moreover, a reasonable mechanism describing the effect of stirring speed on HMF yield was proposed. During the process of high-fructose solution (54.6 wt%) addition, the yields of HMF after four additions in every experiment all exceeded 55%, and a HMF yield of 83.3% was achieved after three additions at 1000 rpm. CONCLUSIONS: The optimization of mechanical stirring in aqueous/butanol media led to a high HMF yield. By studying the kinetics of the fructose-to-HMF reaction, it was demonstrated that a low value of reaction rate constant is of benefit to obtain high HMF yield for this biphasic system. The simple addition process greatly reduced the side-reaction and made the operation more continuous and stable, and thus provided a practical and effective method of HMF preparation in high-fructose solution.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Adsorption, Pollution, Traitement et pollution des eaux, Water treatment and pollution, Pollution des eaux naturelles, Natural water pollution, Eaux souterraines, Groundwaters, Phénomènes biologiques et physicochimiques, Biological and physicochemical phenomena, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biotechnologie, Biotechnology, Méthodes. Procédés. Technologies, Methods. Procedures. Technologies, Méthodes et appareillages divers, Various methods and equipments, Autres, Others, Adsorption, Adsorción, Analyse corrélation, Correlation analysis, Análisis correlación, Biomasse, Biomass, Biomasa, Biosorption, Biosorción, Corrélation, Correlation, Correlación, Décomposition thermique, Thermal decomposition, Descomposición térmica, Eau souterraine, Ground water, Agua subterránea, Homme, Human, Hombre, Modélisation, Modeling, Modelización, Noir carbone, Carbon black, Carbón negro, Pollution eau, Water pollution, Contaminación agua, Production, Producción, Pyrolyse, Pyrolysis, Pirólisis, biosorption, black carbon, chlorinated hydrocarbon, invasive plant species, thermal decomposition, and weed biomass

BACKGROUND: Ambrosia trifida L. (buffalo-weed) is a ubiquitous invasive plant species in Korea, causing severe allergy problems to humans and reduction in crop yields. Converting buffalo-weed biomass to biochar and its use as an adsorbent for the depuration of trichloroethylene (TCE) contaminated water could help resolve two existing environmental issues simultaneously. RESULTS: The plant biomass was converted to biochar at 300 °C (BC300) and 700 °C (BC700). The pyrolysis temperature strongly influenced the properties of resulting biochars. The higher temperature resulted in a higher degree of C-enrichment. The loss of H- and O-containing functional groups shifted the BC700 composition towards a less polar, more aromatic carbon structure evidenced by lower O/C (0.06) and H/C (0.15) values compared with those of BC300 (0.07 and 0.65, respectively). These properties of BC700 further highlighted its greater efficiency of TCE removal (88.47%) from water, compared with that of BC300 (69.07%). The TCE adsorption data was well described by the Hill isotherm model indicating the mechanism of adsorption to be cooperative interaction. Linear correlations between model parameters and biochar properties were also observed. CONCLUSIONS: Buffalo-weed can be converted to value-added biochar that can be used as an effective adsorbent for the treatment of TCE contaminated groundwater.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Réactions catalytiques, Catalytic reactions, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Réacteurs, Reactors, Distillation, Cristallisation, lixiviation, séparations diverses, Crystallization, leaching, miscellaneous separations, Conception, Design, Diseño, Cristallisation, Crystallization, Cristalización, Distillation sous vide, Vacuum distillation, Destilación en vacío, Déchet solide, Solid waste, Residuos sólidos, Eau chaude, Hot water, Agua caliente, Optimisation, Optimization, Optimización, Pureté, Purity, Pureza, Recirculation, Recirculación, Recyclage, Recycling, Reconversión, Réacteur, Reactor, Réaction catalytique, Catalytic reaction, Reacción catalítica, PET wastes, bis(2-hydroxyethyl) terephthalate, glycolysis, process optimization, and recycling

BACKGROUND Glycolysis has been the subject of increased interest as a valuable feedstock recycling for poly(ethylene terephthalate) (PET). However, there are no reports in the technical literature that deal with the design and optimization of the global process. RESULTS Conversion into bis(2-hydroxyethyl) terephthalate (BHET) of the non-glycolyzed solid was feasible, carried out in the presence or absence of fresh PET. The yield varied between 63 and 80%. The monomer was recovered by extraction with hot water followed by crystallization at 4°C. The optimized H2O:BHET ratio was 6.7 mL g-1. The EG(ethylene glycol)/H2O mixture was effectively separated by vacuum distillation and EG of 99.6% purity was recovered, which could be used again. Finally, the highly active catalytic role of sodium carbonate salt for glycolysis was evident not only for transparent PET wastes but also for complex wastes. CONCLUSIONS The recirculation of the solid residue from extraction, the separation of EG/H2O mixture from crystallization and the subsequent refeeding of the organic reactant into the reactor, the minimization of the amount of water to efficiently recover the monomer and the suitability of the chemical recycling of complex PET wastes are operational aspects that significantly increased the global efficiency.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Adsorption, Echange d'ions, Ion exchange, Adsorption, Adsorción, Capacité fixation, Binding capacity, Capacidad de fijación, Chromatographie, Chromatography, Cromatografía, Désorption, Desorption, Desorción, Echangeur anion, Anion exchanger, Cambiador aniónico, Extrait, Extract, Extracto, Industrie pharmaceutique, Pharmaceutical industry, Industria farmacéutica, Potentiel électrocinétique, Electrokinetic potential, Potencial electrocinético, Propriété thermodynamique, Thermodynamic properties, Propiedad termodinámica, Purification, Purificación, pH, antiviral, binding thermodynamics, carbohydrate purification, chromatography, downstream processing, and sulfated polysaccharides

BACKGROUND: Complex polysaccharides are important in the pharmaceutical industry, yet, due to their large molecular weight and reduced charges, their purification is a highly demanding process that requires binding matrices with unique properties. This work demonstrates for the first time that complex polysaccharides biosynthesized by microalga Porphyridium purpureum can be adsorbed onto Q fibrous anion exchangers. RESULTS When the polysaccharides were characterized, the extent of sulfation was higher in native polysaccharides than in ethanol- or alkali-extracts. The zeta potentials increased with increasing pH and the highest charge was observed at pH 8, while the Z-average diameters of the polysaccharide at pH 6 were highest for alkali-extracts. Instead of pellicular resins, Q fibrous adsorbents were used to determine Langmuir thermodynamic properties and dynamic binding capacities. The parameters included static binding capacity and dissociation constant of 13.47 ± 1.02 mg g-1 and 0.141 ± 0.027 mg mL-1, and 10 and 50% breakthrough capacities of 4.46 ± 0.22 and 5.51 ± 0.28 mg g-1, respectively. The antiviral activity of the polysaccharides was demonstrated by minimizing bacteriophage lysis of Streptococcus thermophilus. CONCLUSION This work demonstrates that polysaccharide extraction can be optimized and the adsorption and desorption of a complex polysaccharide onto Q fibrous matrix is feasible. These parameters could be exploited for up-scaling of polysaccharides for nutraceutical and pharmaceutical applications.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Activation, Activación, Analyse corrélation, Correlation analysis, Análisis correlación, Aération, Aeration, Aeración, Cinétique, Kinetics, Cinética, Conception, Design, Diseño, Corrélation, Correlation, Correlación, Désactivation, Deactivation, Desactivación, En discontinu, Batchwise, En discontinuo, Energie activation, Activation energy, Energía activación, Enthalpie, Enthalpy, Entalpía, Inactivation métabolique, Metabolic inactivation, Inactivación metabólica, Logistique, Logistics, Logística, Modèle cinétique, Kinetic model, Modelo cinético, Modélisation, Modeling, Modelización, Métabolisme, Metabolism, Metabolismo, Optimisation, Optimization, Optimización, Production, Producción, Propriété thermodynamique, Thermodynamic properties, Propiedad termodinámica, Santé publique, Public health, Salud pública, Stabilité, Stability, Estabilidad, Bacillus aryabhattai ITBHU02, L-asparaginase, enzyme formation―inactivation kinetics, kinetic modeling, and thermodynamic properties

BACKGROUND: An unstructured model for batch culture production of L-asparaginase by Bacillus aryabhattai ITBHU02, by means of the Luedeking-Piret incorporated logistic equation, was developed explaining the correlation between growth dynamics and enzyme production kinetics with respect to glucose depletion at different levels. The main goal was to build up a means for process optimization, design, control and analysis of L-asparaginase production. Various thermodynamic parameters were estimated to comprehend enzyme stability and affiliated industrial applicability. RESULTS: Specific growth rate maxima were increased with increasing initial glucose concentration, whereas the specific productivity was best supported at a glucose concentration 5.0 g L-1. The fermentative production of L-asparaginase was greatly influenced by oxygen supply, reaching a maximum level at an aeration rate of 0.6 vvm. The activation energies for growth and death rate were 33.8±6.0 and 99.8±9.0 kJ mol-1, respectively, with activation enthalpy values of enzyme formation and thermal deactivation 70.2±9.0 and 46.1 ±11.0 kJ mol-1, respectively. CONCLUSION: The economic production of L-asparaginase by B. aryabhattai was achieved efficiently at low glucose concentration and mild aeration. Endogenous metabolism of the strain for L-asparaginase synthesis was thermostable up to 40°C, which makes the strain commercially important as it can be utilized for cost-effective L-asparaginase production within countries such as India, where 35-40°C temperatures are quite common.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Bois, Wood, Madera, Conception, Design, Diseño, Extrait, Extract, Extracto, Industrie pétrochimique, Petrochemical industry, Industria petroquímica, Optimisation, Optimization, Optimización, Pression atmosphérique, Atmospheric pressure, Presión atmosférica, Production, Producción, Structure chimique, Chemical structure, Estructura química, Fagus sylvatica L, chemical structure, formic/acetic acid treatment, lignin, and response surface methodology

BACKGROUND: In order to replace petrochemicals by bio-based lignin products in high value-added applications, a formic/acetic acid treatment was adapted to beech wood (Fagus sylvatica L.) for lignin extraction. RESULTS: Beech wood particles were delignified at atmospheric pressure by a formic acid/acetic acid/water mixture. Cooking time and temperature were optimized for delignification, pulp yield and 2-furfural concentration. Response surface design analysis revealed that delignification yield increased with cooking time and temperature. CONCLUSION: The multi-criteria optimization of delignification was used to find the ideal cooking conditions (5 h 07 min, 104.2 °C) to maximize delignification (70.5%) and pulp yield (58.7%) and, to a lesser extent, minimize 2-furfural production. Treatment conditions were found to influence the chemical structure of extracted lignins. Cooking time and temperature inversely influenced lignin molecular weights.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Réactions catalytiques, Catalytic reactions, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Réacteurs, Reactors, Echange d'ions, Ion exchange, Activité catalytique, Catalyst activity, Actividad catalítica, Analyse spectrale, Spectral analysis, Análisis espectral, Catalyseur, Catalyst, Catalizador, Liquide ionique, Ionic liquid, Líquido iónico, Métathèse, Metathesis, Metatesis, Préparation, Preparation, Preparación, Résine échangeuse anion, Anionic resin, Resina de cambio aniónico, Stabilité thermique, Thermal stability, Estabilidad térmica, Transestérification, Transesterification, Transesterificación, fatty acid esters, ionic liquids, and transesterification

BACKGROUND: Alkylguanidinium and alkylamidinium hydroxides have been developed as new basic ionic liquids for the first time from cyclic guanidine (TBD) and amidines (DBN, DBU). The method of preparation of [bmim]OH decribed in the literature was adopted for the synthesis of new ionic liquids. Synthesis was carried out using cyclohexane as the solvent for the synthesis of alkylguanidine and alkylamidine bromides. Anion metathesis was carried out over anionic resins in water as solvent. The structures of the new ionic liquids were confirmed by spectral analysis. The catalytic activity of the new ionic liquids was tested in transesterification of fatty acid methyl esters with trimethylolpropane, neopentyl glycol and 2-ethylhexyl alcohol. RESULTS: The new ionic liquids have good thermal stability and can be applied for transesterification processes. The highest conversion of FAME (83%) was obtained for TMP ester of oleic acid and ionic liquid [TBD-Bu]OH. CONCLUSION: Among the ionic liquids derived from cyclic guanidine and amidine only ionic liquids obtained from TBD are good catalysts for transesterification of FAME and polyols. In comparision with [bmim]OH, catalytic activity of TBD ionic liquids was comparable in the synthesis of TMP ester but better in the synthesis of 2EH esters.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Biomasse, Biomass, Biomasa, Combustible, Fuel, Compétitivité, Competitiveness, Competitividad, Conversion catalytique, Catalytic conversion, Conversión catalítica, Marché, Markets, Mercado, Production, Producción, Précurseur, Precursor, Pétrole, Petroleum, Petróleo, biochemicals, biofuels, biorefinery, fuel precursor, furfural, and lignocellulosic biomass

Furfural is a natural precursor to furan-based chemicals and has the potential to become a major renewable platform chemical for the production of biochemicals and biofuels. However, current industrial furfural production relies on relatively old and inefficient strategies that have hindered its capacity, and low production yields have strongly diminished its competitiveness with petroleum-based alternatives in the global market. This mini-review provides a critical analysis of past and current progress to enhance furfural production from lignocellulosic biomass. First, important chemical and fuel products derived from the catalytic conversion of furfural are outlined. We then discuss the importance of developing integrated production strategies to co-produce furfural with other valuable chemicals. Furfural formation and loss chemistries are explored to understand effective methods to improve furfural yields from pentosans. Finally, selected relevant commercial and academic technologies that promise to improve lignocellulosic furfural production are discussed.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Carburant diesel, Diesel fuel, Carburante diesel, Catalyse basique, Base catalysis, Catálisis básica, Combustible fossile, Fossil fuel, Combustible fósil, Combustion, Combustión, Dopage, Doping, Etat supercritique, Supercritical state, Estado supercrítico, Production, Producción, Spectrométrie absorption RX, X ray absorption spectrometry, Espectrometría absorción RX, Substitut, Substitute, Substituto, Transestérification, Transesterification, Transesterificación, Cs, MgO, XAS, biodiesel, and solid base

BACKGROUND: Biodiesel is a clean-burning, renewable and biodegradable diesel fuel substitute derived from animal fats and plant oils, which may play an important role in replacing diminishing fossil fuel reserves and combating climate change. Conventional biodiesel production uses soluble base catalysts, such as Na or K alkoxides, to convert oils into fuel, and as a result requires energy intensive aqueous quench cycles to isolate the biodiesel product. RESULTS: Cs-doping nanoparticulate MgO, prepared via a novel, supercritical sol―gel method, yields a solid base catalyst with improved activity for the transesterification of pure triacylglycerides (TAGs) and olive oil. CONCLUSION: Here, X-ray absorption spectroscopy (XAS) is used to probe the local chemical environment of Cs atoms in order to identify the nature of the catalytically active species as Cs2Mg(CO3)2(H2O)4.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Réacteurs, Reactors, Pollution, Traitement et pollution des eaux, Water treatment and pollution, Eaux usées, Wastewaters, Procédés généraux d'épuration, General purification processes, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biotechnologie, Biotechnology, Méthodes. Procédés. Technologies, Methods. Procedures. Technologies, Méthodes et appareillages divers, Various methods and equipments, Autres, Others, Eau usée industrielle, Industrial waste water, Agua servida industrial, Eau usée, Waste water, Agua residual, Fabrication, Manufacturing, Fabricación, Lixiviation bactérienne, Bacterial leaching, Lixiviación bacteriana, Métal lourd, Heavy metal, Metal pesado, Pollution, Polución, Recyclage, Recycling, Reconversión, Réacteur SBR, Sequencing batch reactor, Reactor SBR, Solubilisation, Solubilization, Solubilización, Thermophilie, Thermophily, Termofilia, pH, Déchet électronique, Electronic scrap, bioleaching, printed circuit board, sequencing batch reactor, thermophilic, and wastewater sludge

BACKGROUND: A large quantity of heavy metal contaminated wastewater sludge is produced during the treatment of printed circuit board (PCB) manufacturing wastewater. The PCB wastewater sludge containing high concentrations of heavy metals, such as Cu and Zn, increases the potential for metal recycling. Although bioleaching is indicated as a promising technology to remove metals from electronic scrap and waste PCBs, its application for metal recovery from PCB wastewater sludge is still very limited. The purpose of this study was to develop a thermophilic bioleaching process operated in a sequencing batch reactor (SBR) to recover heavy metals from PCB wastewater sludge. RESULTS: The results show that an increase in sludge solid content from 0.5 to 5% (w/v) decreased the rate of pH reduction during the bioleaching process. It was also found that the efficiency and rate of metal solubilization decreased with increasing sludge solid content. At a sludge solid content of 0.5% (w/v), after four repeated feed/decant cycles with 10 days per cycle (40 days) of SBR operation, the maximum efficiencies of metal solubilization in the treated sludge were 65% and 100% for Cu and Zn, respectively. CONCLUSION: The solubilization efficiency of heavy metals was lower during SBR operation with a longer 20-day cycle time. Therefore, a shorter 10-day cycle time for SBR operation is preferred for the thermophilic bioleaching of PCB wastewater sludge. In the treated sludge, the potential mobility and environmental risks of heavy metals were decreased significantly after the thermophilic bioleaching process.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biotechnologie, Biotechnology, Méthodes. Procédés. Technologies, Methods. Procedures. Technologies, Méthodes et appareillages divers, Various methods and equipments, Autres, Others, Biomasse, Biomass, Biomasa, Chargement, Loading, Cargamento, Combustible, Fuel, Eau chaude, Hot water, Agua caliente, Fermentation, Fermentación, Modèle mathématique, Mathematical model, Modelo matemático, Modélisation, Modeling, Modelización, Paille, Straw, Paja, Plan expérience, Experimental design, Plan experiencia, Production, Producción, Prétraitement, Pretreatment, Pretratamiento, Surveillance, Vigilancia, biomass, fuel ethanol, rapeseed straw, response surface methodology, and simultaneous saccharification and fermentation (SSF)

BACKGROUND: Rapeseed straw is an agricultural residue increasingly produced in recent years due to a growing interest in biodiesel production. In the present study, rapeseed straw pretreated by liquid hot water was tested as a substrate to optimize ethanol production by simultaneous saccharification and fermentation (SSF). Temperature, time, substrate loading and cellulase charge were selected as operation variables and modified according to a three-level four-variable experimental design. Ethanol concentration, ethanol yield and volumetric productivity were monitored and adjusted to a quadratic model using response surface methodology. RESULTS: Optimal SSF conditions, based on the mathematical model in terms of ethanol yield and concentration, were found to be 40°C, 71 h, 10% substrate loading, and 40 FPU g―1 substrate. The resulting ethanol concentration was 23 g L―1, which corresponds to 69% ethanol yield. CONCLUSION: Liquid hot water is an effective pretreatment that increased the cellulose concentration of rapeseed straw, making it a good substrate for SSF, with a maximum yield of 0.12 g ethanol g-1 dry straw. The novel combination of hydrothermal pretreatment and SSF configuration results in yields comparable yields with those previously reported, and has additional advantages, e.g. no chemicals use and high solid concentration operation.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Pollution, Pollution atmosphérique, Atmospheric pollution, Méthodes de prévention et d'épuration, Prevention and purification methods, Procédés généraux d'épuration et de dépoussiérage, General processes of purification and dust removal, Dénitrification, Denitrification, Desnitrificación, Epuration effluent gazeux, Flue gas purification, Depuración efluente gaseoso, Modélisation, Modeling, Modelización, denitrification, iron reduction, nitric oxide, respiratory inhibitor, and sulfide

BACKGROUND: The integrated approach of using metal chelate (e.g. Fe(II)EDTA) absorption combined with microbial reduction for nitric oxide (NO) removal has been a frequent topic of much recent study. The present study was undertaken to evaluate simultaneous Fe(II)EDTA-NO and Fe(III)EDTA with Paracoccus denitrificans as a model microorganism. RESULTS: The experimental results suggested that Fe(III)EDTA reduction was severely inhibited by Fe(II)EDTA-NO while the addition of Fe(III)EDTA could have a positive effect on the reduction of Fe(II)EDTA-NO. Riboflavin, AQDS and vitamin B12 at 0.1 mmol L―1 did not have significant effects on simultaneous reduction of Fe(II)EDTA-NO and Fe(III)EDTA. Addition of sulfide not only could directly react with Fe(II)EDTA-NO and Fe(III)EDTA but also might play multiple roles in biological Fe(II)EDTA-NO reduction and Fe(III)EDTA reduction. The respiratory inhibitor CuCl2 inhibited Fe(II)EDTA-NO reduction as well as Fe(III)EDTA reduction while NaN3 and rotenone showed no measurable effects. CONCLUSIONS: The present study showed that Fe(II)EDTA-NO reduction and Fe(III)EDTA reduction reacted upon each other. The roles of sulfide were divided in terms of biological and chemical interactions during the simultaneous reduction. CuCl2 could inhibit the simultaneous reduction rates.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Réactions catalytiques, Catalytic reactions, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Transferts de chaleur et de matière. Garnissages, plateaux de contact, Heat and mass transfer. Packings, plates, Réacteurs, Reactors, Energie renouvelable, Renewable energy, Energía renovable, Acier inoxydable, Stainless steel, Acero inoxidable, Diffusion, Difusión, Energie éolienne, Wind energy, Energía eólica, Mélangeage, Mixing, Mezclado, Oxyde de titane, Titanium oxide, Titanio óxido, Photocatalyse, Photocatalysis, Fotocatálisis, Rayonnement UV, Ultraviolet radiation, Radiación ultravioleta, Rayonnement solaire, Solar radiation, Radiación solar, Réacteur catalytique, Catalytic reactor, Reactor catalítico, Réfractaire, Refractory, Refractario, Solution aqueuse, Aqueous solution, Solución acuosa, Transfert masse, Mass transfer, Transferencia masa, catalytic reactors, mass transfer, photocatalysis, and reaction

BACKGROUND: TiO2-based heterogeneous photocatalysis is an effective way to degrade harmful refractory organic compounds. However, the rate of photocatalytic reaction is significantly decreased by film diffusion resistance and several other factors. To overcome this problem, TiO2 immobilized on a stainless steel screen is hydrophobically treated using a (γ-aminopropyl) triethoxysilane-toluene solution and the performance of the silanized TiO2 for the photocatalytic decomposition of 2,4-dinitrophenol (2,4-DNP) is investigated. RESULTS: The reactant 2,4-DNP is slowly decomposed when its aqueous solution is treated using an unsilanized TiO2 screen without mixing the solution, whereas the rate of decomposition is certainly increased by use of a silanized TiO2 screen, and further increased by mixing the solution. The use of sunlight as a UV light source provides a higher rate of decomposition than does the use of an artificial UV lamp. The rate of decomposition in a well-mixed solution is less affected up to 1.5 cm in solution depth. CONCLUSIONS: The use of the TiO2 screen silanized with a 2% silane―toluene solution under liquid mixing decreases film diffusion resistance and facilitates rapid decomposition of 2,4-DNP. The simultaneous use of sunlight as a UV light source and a wind-powered propeller for liquid mixing is effective.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Réactions catalytiques, Catalytic reactions, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Réacteurs, Reactors, Biomasse, Biomass, Biomasa, Catalyseur, Catalyst, Catalizador, In situ, Production, Producción, Teneur eau, Water content, Dosis agua, Transestérification, Transesterification, Transesterificación, biodiesel, lipid extraction, microalgae, and wet biomass

BACKGROUND: A major hurdle with algal biodiesel production has been the energy required to dry algal biomass prior to lipid extraction and/or conversion. Water interferes with the extraction and/or conversion of algal lipids to biodiesel. The focus of this study was to evaluate the efficiency of the in situ transesterification method for biodiesel recovery when processing algal biomass with varying amounts of moisture and to evaluate changes in efficiency as in situ transesterification reaction parameters were varied. RESULTS: Results indicated that moisture content affected biodiesel recovery. Specifically, algal biomass moisture contents above 20% by mass led to statistically significant reductions in biodiesel recovery. However, increasing the amount of catalyst and/or methanol in the reaction resulted in higher recoveries when using wet algal biomass containing 84% moisture. Using 10% (v/v) sulfuric acid in methanol with the wet biomass to solution ratio of 25 mg (dry mass equivalent) mL-1 resulted in the recovery of approximately 81 % of the maximum biodiesel yield. CONCLUSION: This study showed that the presence of moisture at greater than 20% by mass in algal biomass significantly decreased biodiesel recovery when using in situ transesterification. Increasing the amount of methanol and/or catalyst in the reaction improved biodiesel recovery from wet algal biomass.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Réactions catalytiques, Catalytic reactions, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Réacteurs, Reactors, Catalyse hétérogène, Heterogeneous catalysis, Catálisis heterogénea, Dioxyde de carbone, Carbon dioxide, Carbono dióxido, Gaz effet serre, Greenhouse gas, Gas efecto invernadero, Production, Producción, Réchauffement, Warming, Calefacción, carbon dioxide, cerium oxide, cyclic carbamate, cyclic carbonate, and cyclic urea

CO2 has a large effect on global warming by greenhouse gases, and development of an effective technique for the reduction of CO2 is a crucial and urgent issue. From the chemical viewpoint, CO2 is regarded as a stable, safe and abundant C1 resource, and the transformation of CO2 to valuable chemicals is promising not only for reduction of CO2 but also for production of useful chemicals. This mini-review focuses on the direct conversion of CO2 with diols, aminoalcohols and diamines to cyclic compounds such as cyclic carbonates, cyclic carbamates and cyclic ureas, and in particular discusses the mechanisms for these reactions over heterogeneous catalysts.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Réacteurs, Reactors, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biotechnologie, Biotechnology, Méthodes. Procédés. Technologies, Methods. Procedures. Technologies, Méthodes et appareillages divers, Various methods and equipments, Autres, Others, Propriété thermodynamique, Thermodynamic properties, Propiedad termodinámica, Affinité, Affinity, Afinidad, Bioréacteur, Bioreactor, Biorreactor, Coefficient activité, Activity coefficient, Coeficiente actividad, Coefficient partage, Partition coefficient, Coeficiente repartición, Critère sélection, Selection criterion, Criterio selección, Dégradation biologique, Biodegradation, Degradación biológica, Partage phase, Phase partition, Repartición fase, Pollution, Polución, Prédiction, Prediction, Predicción, Solubilité, Solubility, Solubilidad, TPPB, biodegradation, polymer selection, polymer thermodynamics, and solubility parameter

BACKGROUND: Solid-liquid two-phase partitioning bioreactors (TPPBs) use polymers as the sequestering phase to reduce the concentration of substrates to sub-inhibitory levels and enhance biodegradation performance. Polymer selection for TPPBs is challenging due to the almost infinite variety of target substrates to be degraded, and the variability and complexity of polymer composition and structure. RESULTS: Three different polymer selection criteria, based on either solubility parameters or activity coefficients, were assessed via experimental partitioning coefficients (PCs) for phenol and butyl acetate, two substantially different target contaminant molecules, and the relative ability of the three methods to predict effective polymers was assessed. The best method was also applied to predict which waste polymers would be effective for sequestering these molecules, and TPPB degradation tests were conducted to confirm the effectiveness of a single identified polymer and selected waste polymers. CONCLUSION: An effective polymer selection criterion was identified and the identified polymer showed a high capacity to absorb both phenol and butyl acetate. Both substrates were successfully degraded in solid-liquid TPPBs using the selected polymer and using mixtures of waste polymers.

Biotechnology, Biotechnologies, Chemical engineering, Génie chimique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Chimie, Chemistry, Chimie generale et chimie physique, General and physical chemistry, Théorie des réactions, cinétique générale. Catalyse. Nomenclature, documentation chimique, informatique chimique, Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry, Catalyse, Catalysis, Réactions catalytiques, Catalytic reactions, Sciences appliquees, Applied sciences, Genie chimique, Chemical engineering, Réacteurs, Reactors, Microréacteur, Microreactor, Modèle mathématique, Mathematical model, Modelo matemático, Modélisation, Modeling, Modelización, Oxydation, Oxidation, Oxidación, Prédiction, Prediction, Predicción, Réaction catalytique, Catalytic reaction, Reacción catalítica, pH, NAD+, coenzyme regeneration, mathematical modelling, and microreactor

BACKGROUND: The coenzyme NAD+ (nicotinamide adenine dinucleotide) is commonly used in biocatalytic oxidations catalysed by the enzyme alcohol dehydrogenase (ADH). As the price of the coenzyme NAD+ is extremely high, it is essential to regenerate the reduced form of the coenzyme back into the oxidized form. In this work the regeneration of the coenzyme NAD+ was carried out in a microreactor by reversible oxidation of ethanol to acetaldehyde with the ADH enzyme. RESULTS: A 100% conversion of NADH was achieved for a residence time of just τ = 0.8 s when the concentration of acetaldehyde was in excess (ci,NADH = 5.5 mmol dm-3, Ci,acetaldehyde = 44 mmol dm-3, γi,ADH = 0.2 g dm-3, 75 mmol dm-3 glycine-pyrophosphate buffer pH = 9; T = 25°C). A 2D mathematical model for the description and prediction of microreactor performance was developed. Model simulations were validated using data from independent experiments. CONCLUSION: The high conversions that were obtained for short residence times mean thatthe microreactors can be considered as good and efficient methods for coenzyme regeneration.