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Juan Carlos Parajo - One of the best experts on this subject based on the ideXlab platform.
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invasive biomass valorization environmentally friendly processes for obtaining second generation bioethanol and saccharides from ulex europaeus
Journal of Chemical Technology & Biotechnology, 2013Co-Authors: Iria Ana Arespeon, Gil Garrote, Aloia Romani, Juan Carlos ParajoAbstract:BACKGROUND Ulex europaeus (UE) is a widespread invasive shrub species causing economic problems and environmental hazards. This work deals with the valorization of UE by Hydrothermal Processing (to obtain hemicelluloses-derived saccharides) followed by simultaneous saccharification and fermentation of the resulting solids for manufacturing second generation bioethanol. RESULTS Hydrothermal Processing of UE resulted in the solubilization of up to 21.5 wt% of the oven-dry raw material, leading to the formation of hemicelluloses-derived saccharides as major reaction products. Treatments at various severities resulted in processed solids with enhanced susceptibility to enzymatic hydrolysis, allowing cellulose to glucose conversions up to 87%. Simultaneous saccharification and fermentation of solids pretreated under selected conditions, performed at various charges and solid loadings, resulted in bioethanol conversions up to 82% of the stoichiometric amount, with volumetric concentrations higher than 30 g ethanol L-1. CONCLUSION Hydrothermal Processing of UE followed by simultaneous saccharification and fermentation of pretreated solids was suitable for the selective separation of hemicelluloses as soluble saccharides and for the manufacture of second generation bioethanol at high yield from the pretreated solids.© 2012 Society of Chemical Industry
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effects of Hydrothermal Processing on the cellulosic fraction of eucalyptus globulus wood
Holzforschung, 2013Co-Authors: Carlos Vila, Jose Luis Francisco, Valentin Santos, Juan Carlos ParajoAbstract:The effects of Hydrothermal treatments of Eucalyptus globulus wood have been evaluated in terms of the solid yield and the composition of the treated wood. The contents of cellulose, xylan, and Klason lignin in treated solids were determined and interpreted by means of kinetic models. Particular attention was paid to the degree of polymerization (DP) lowering of cellulose caused by Hydrothermal treatments, which was assessed by measurements of intrinsic viscosity.
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experimental assessment on the enzymatic hydrolysis of Hydrothermally pretreated eucalyptus globulus wood
Industrial & Engineering Chemistry Research, 2010Co-Authors: Aloia Romani, Gil Garrote, Jose Luis Alonso, Juan Carlos ParajoAbstract:Hydrothermal Processing of Eucalyptus globulus wood was evaluated as a pretreatment for bioethanol manufacture, to assess the effects caused by the severity of wood solubilization, composition of l...
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Hydrothermal Processing of rice husks effects of severity on product distribution
Journal of Chemical Technology & Biotechnology, 2008Co-Authors: Rodolfo Vegas, Jose Luis Alonso, Mirjam A Kabel, Henk A Schols, Juan Carlos ParajoAbstract:BACKGROUND: Treatment in aqueous media (Hydrothermal or autohydrolysis reactions) is an environmentally friendly technology for fractionating lignocellulosic materials. Rice husks were subjected to Hydrothermal Processing under a variety of operational conditions to cause the selective breakdown of xylan chains, in order to assess the effects of reaction severity on the distribution of reaction products. RESULTS: The effects of severity (measured by the severity factor, R0) on the concentrations of the major autohydrolysis products (monosaccharides, xylo- and glucooligosaccharides, xylooligosaccharide substituents, acetic acid, acid-soluble lignin and elemental nitrogen) were assessed. The interrelationship between the severity of treatment and molecular weight distribution was established by high-performance size-exclusion chromatography. Selected samples were subjected to refining treatments as ethyl acetate extraction and ion exchange for refining purposes, and the concentrates were assayed by high-performance anion-exchange chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. CONCLUSIONS The protein equivalent of the products present in liquors accounted for 43 to 51% of the protein present in the raw rice husks. The concentrations of glucose (derived from starchy material) and arabinose (split from the xylan backbone) were fairly constant with severity. Even in treatments at low severity, high molecular weight compounds derived from xylan accounted for a limited part of the stoichiometric amount. Operating under harsh conditions, about 50% of the total xylan-derived compounds corresponded to fractions with a degree of polymerization (DP) <9. After refining, saccharides accounted for more than 90% of the non-volatile components of the sample. The refined products showed a series of xylose oligomers up to about DP 13, and a series of acetylated xylose oligomers up to about DP 15.
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coproduction of oligosaccharides and glucose from corncobs by Hydrothermal Processing and enzymatic hydrolysis
Industrial & Engineering Chemistry Research, 2008Co-Authors: Gil Garrote, Remedios Yanez, And Jose Luis Alonso, Juan Carlos ParajoAbstract:Corncobs were subjected to nonisothermal reaction in aqueous conditions to reach temperatures in the range 202−216 °C. The liquors were assayed for composition to assess the conversion of xylan into oligosaccharides and reaction byproducts, whereas the spent solids from treatments were subjected to enzymatic hydrolysis. Enzymatic assays were carried out according to an incomplete, factorial, centered design of experiments, in which the following independent variables were considered: liquor to solid ratio (in the range 6−16 g/g), enzyme to substrate ratio (in the range 6−28 filter paper units/g), and β-glucosidase activity/cellulase activity ratio (in the range 1−9 IU/FPU). The concentration/time data were fitted to an equation selected from the literature, and the model parameters were expressed as a function of the operational variables considered in the experimental design. Under selected conditions, high oligosaccharide yields and near quantitative cellulose conversion into glucose were obtained.
S.g. Uma - One of the best experts on this subject based on the ideXlab platform.
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effects of Hydrothermal Processing on nutritional value of canavalia ensiformis and its utilization by clarias gariepinus burchell 1822 fingerlings
Aquaculture Reports, 2016Co-Authors: V.t. Okomoda, L.o. Tiamiyu, S.g. UmaAbstract:Abstract Jack bean ( Canavalia ensiformis ) is one of the underutilized legumes in animal feed production partly because of its high antinutritional factors. This study investigated the nutritional value of C. ensiformis seed subjected to Hydrothermal Processing in the diet of the African catfish Clarias gariepinus . Five batches of C. ensiformis seeds were Hydrothermally processed in boiling water (100 °C) for 0, 10, 20, 30 and 40 min, respectively. Proximate composition of the seed showed no significant effect of Hydrothermal Processing on protein and fat content of C. ensiformis . However, all essential amino acids were significantly affected. The anti-nutritional factor canavanine was not markedly reduced even at 40 min Hydrothermal Processing. Fifty fingerlings of C. gariepinus (1.07 ± 0.01 g) were stocked in 15 hapas measuring 1 × 1 × 1m 3 , labeled in triplicate according to five isonitrogenous diets (35% CP) formulated using the processed C. ensiformis seed at an inclusion level of 27%. The highest body weight gain (2.73 g), specific growth rate (2.26gday −1 ), feed conversion efficiency (34.11%) and protein efficiency ratio (0.078) were observed at Hydrothermal treatment of 30 and 40 min. Hydrothermal Processing of C. ensiformis up to 40 min could be exploited in the commercial and on-farm production of catfish diet at 27% level of inclusion.
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Effects of Hydrothermal Processing on nutritional value of Canavalia ensiformis and its utilization by Clarias gariepinus (Burchell, 1822) fingerlings
Elsevier, 2016Co-Authors: V.t. Okomoda, L.o. Tiamiyu, S.g. UmaAbstract:Jack bean (Canavalia ensiformis) is one of the underutilized legumes in animal feed production partly because of its high antinutritional factors. This study investigated the nutritional value of C. ensiformis seed subjected to Hydrothermal Processing in the diet of the African catfish Clarias gariepinus. Five batches of C. ensiformis seeds were Hydrothermally processed in boiling water (100 °C) for 0, 10, 20, 30 and 40 min, respectively. Proximate composition of the seed showed no significant effect of Hydrothermal Processing on protein and fat content of C. ensiformis. However, all essential amino acids were significantly affected. The anti-nutritional factor canavanine was not markedly reduced even at 40 min Hydrothermal Processing. Fifty fingerlings of C. gariepinus (1.07 ± 0.01 g) were stocked in 15 hapas measuring 1 × 1 × 1m3, labeled in triplicate according to five isonitrogenous diets (35% CP) formulated using the processed C. ensiformis seed at an inclusion level of 27%. The highest body weight gain (2.73 g), specific growth rate (2.26gday−1), feed conversion efficiency (34.11%) and protein efficiency ratio (0.078) were observed at Hydrothermal treatment of 30 and 40 min. Hydrothermal Processing of C. ensiformis up to 40 min could be exploited in the commercial and on-farm production of catfish diet at 27% level of inclusion. Keywords: Jack bean, Unconventional feed, Hydrothermal, Anti-nutritional factor, African catfis
Jose Luis Alonso - One of the best experts on this subject based on the ideXlab platform.
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experimental assessment on the enzymatic hydrolysis of Hydrothermally pretreated eucalyptus globulus wood
Industrial & Engineering Chemistry Research, 2010Co-Authors: Aloia Romani, Gil Garrote, Jose Luis Alonso, Juan Carlos ParajoAbstract:Hydrothermal Processing of Eucalyptus globulus wood was evaluated as a pretreatment for bioethanol manufacture, to assess the effects caused by the severity of wood solubilization, composition of l...
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Hydrothermal Processing of rice husks effects of severity on product distribution
Journal of Chemical Technology & Biotechnology, 2008Co-Authors: Rodolfo Vegas, Jose Luis Alonso, Mirjam A Kabel, Henk A Schols, Juan Carlos ParajoAbstract:BACKGROUND: Treatment in aqueous media (Hydrothermal or autohydrolysis reactions) is an environmentally friendly technology for fractionating lignocellulosic materials. Rice husks were subjected to Hydrothermal Processing under a variety of operational conditions to cause the selective breakdown of xylan chains, in order to assess the effects of reaction severity on the distribution of reaction products. RESULTS: The effects of severity (measured by the severity factor, R0) on the concentrations of the major autohydrolysis products (monosaccharides, xylo- and glucooligosaccharides, xylooligosaccharide substituents, acetic acid, acid-soluble lignin and elemental nitrogen) were assessed. The interrelationship between the severity of treatment and molecular weight distribution was established by high-performance size-exclusion chromatography. Selected samples were subjected to refining treatments as ethyl acetate extraction and ion exchange for refining purposes, and the concentrates were assayed by high-performance anion-exchange chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. CONCLUSIONS The protein equivalent of the products present in liquors accounted for 43 to 51% of the protein present in the raw rice husks. The concentrations of glucose (derived from starchy material) and arabinose (split from the xylan backbone) were fairly constant with severity. Even in treatments at low severity, high molecular weight compounds derived from xylan accounted for a limited part of the stoichiometric amount. Operating under harsh conditions, about 50% of the total xylan-derived compounds corresponded to fractions with a degree of polymerization (DP) <9. After refining, saccharides accounted for more than 90% of the non-volatile components of the sample. The refined products showed a series of xylose oligomers up to about DP 13, and a series of acetylated xylose oligomers up to about DP 15.
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enzymatic saccharification of hydrogen peroxide treated solids from Hydrothermal Processing of rice husks
Process Biochemistry, 2006Co-Authors: Remedios Yanez, Jose Luis Alonso, Juan Carlos ParajoAbstract:Rice husks were subjected to Hydrothermal Processing in aqueous medium to cause the degradation of xylan to xylooligosaccharides. The resulting solid phase, with enhanced contents of cellulose and lignin, was assayed as a substrate for enzymatic hydrolysis either directly or after treatments with hydrogen peroxide in alkaline media under a variety of operational conditions. Solid yield, solid composition and susceptibility to enzymatic hydrolysis were assessed by empirical modelling. The susceptibility of the solids to enzymatic hydrolysis was greatly improved by peroxide treatments. Under selected conditions (oxidizing treatments with 50 g hydrogen peroxide/100 g solids at 80 °C for 4 h using a liquor to solid ratio of 15 g/g) lignin was removed in high proportion, and cellulose was almost quantitatively recovered in solid phase. In the subsequent enzymatic hydrolysis (using an enzyme/substrate ratio of 25 FPU/g at liquor to solid ratio of 15 g/g for 48 h), 67.9% of cellulose was converted into glucose, leading to a medium containing 43.5 g glucose/L. Higher cellulose conversions were achieved when the liquor to solid ratio employed in the enzymatic hydrolysis was increased, but then the final glucose concentrations decreased owing to the higher amount of liquid.
Rustum Roy - One of the best experts on this subject based on the ideXlab platform.
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microwave Hydrothermal Processing of bifeo3 and csal2po6
ChemInform, 1996Co-Authors: Sridhar Komarneni, Rustum Roy, V C Menon, F AingerAbstract:Microwave-Hydrothermal (M-H) Processing was compared with conventional-Hydrothermal (C-H) Processing in the crystallization of BiFeO3 and CsAl2PO6 phases. The presence of the microwave field led to accelerated kinetics of the crystallization of both these phases as detected by powder X-ray diffraction. The acceleration of reaction rates under microwave field is expected to lead to energy savings during ceramic Processing.
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microwave Hydrothermal Processing of layered anion exchangers
Journal of Materials Research, 1996Co-Authors: Sridhar Komarneni, Rustum RoyAbstract:We have compared the microwave-Hydrothermal (M-H) Processing with conventional Hydrothermal (C-H) Processing in the preparation of two layered anion exchangers, i.e., Mg3Al(OH)8NO3 · nH2O and Ni1-xZn2x(OH)2(CH3COO)2x · nH2O. Both these phases can be crystallized more rapidly (an order of magnitude) under M-H Processing compared to C-H Processing. The above layered mixed basic salt of Ni and Zn was found to exhibit very high selectivity for PO4= (Kd = 15,000). Its order of selectivity for various anions in the presence of 0.1 N NaC1 (ratio of C1- to anion in question is 100) increases as follows: PO4= ≫ SO4 = > NO3-.
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microwave Hydrothermal Processing of metal powders
Journal of Materials Research, 1995Co-Authors: Sridhar Komarneni, Rajyalakshmi Pidugu, Rustum RoyAbstract:Novel microwave-Hydrothermal Processing has been developed by us recently for the synthesis of a wide variety of ceramic powders. Herein, we report the use of microwave-Hydrothermal Processing to synthesize several metal powders such as Cu, Ni, Co, and Ag by reducing their corresponding metal salts or hydroxides with ethylene glycol. Metal powders have been produced extremely rapidly a (few minutes) by microwave catalysis. The kinetics of metal powder synthesis have been increased by at least an order of magnitude by microwave-Hydrothermal Processing compared to the conventional refluxing process in ethylene glycol at about 195 °C.
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microwave Hydrothermal Processing for synthesis of layered and network phosphates
Journal of Materials Chemistry, 1994Co-Authors: Sridhar Komarneni, Rustum RoyAbstract:Novel microwave–Hydrothermal Processing was used to increase the kinetics of the synthesis of technologically important layered and network phosphates by one to two orders of magnitude. The new powder Processing technique, which is ‘environmentally benign’, appears to favour the formation of layered phases. A new 13.2 A[d(001)] layered Ti phosphate has been synthesized by this technique. This phase shows high caesium exchange selectivity and it may be useful for separation of radioactive Cs from acidic nuclear wastes and in decontamination of the environment after accidental releases of Cs.
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microwave Hydrothermal Processing for synthesis of electroceramic powders
Journal of Materials Research, 1993Co-Authors: Sridhar Komarneni, Karin M Stefansson, Rustum RoyAbstract:Microwave-Hydrothermal Processing has so far been used only to dissolve inorganic solids for chemical analysis. We report herein the use of microwave-Hydrothermal Processing to synthesize various ceramic powders in binary and polynary systems. We describe the synthesis of some electroceramic powders such as BaTiO3, SrTiO3, Sr0.5Ba0.5TiO3, PbTiO3, BaZrO3, SrZrO3, Pb(Zr0.52Ti0.48)O3, and pyrochlore phases with the Pb(Mg1/3Nb2/3)O3 and Pb(Zn1/3Nb2/3)O3 compositions by this novel microwave-Hydrothermal Processing technique.
Sridhar Komarneni - One of the best experts on this subject based on the ideXlab platform.
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microwave Hydrothermal Processing of titanium dioxide
Materials Chemistry and Physics, 1999Co-Authors: Sridhar Komarneni, Rama K Rajha, Hiroaki KatsukiAbstract:Abstract Microwave-Hydrothermal synthesis of titanium dioxide under various reaction conditions is reported. Crystallization of rutile from TiOCl 2 solutions was found to be extremely rapid. Titanium dioxide particle size, morphology and polymorph can be controlled by changing various parameters such as concentration, pH, pressure (or temperature), time and anionic species. The main advantages of microwave-Hydrothermal Processing of TiO 2 are (a) rapid heating to temperature and (b) extremely rapid kinetics of crystallization, both are expected to lead to energy savings.
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microwave Hydrothermal synthesis of nanophase ferrites
ChemInform, 1999Co-Authors: Sridhar Komarneni, Maria Cristina Darrigo, Cristina Leonelli, Gian Carlo Pellacani, Hiroaki KatsukiAbstract:This paper reports the synthesis of technologically important ferrites such as ZnFe 2 O 4 , NiFe 2 O 4 , MnFe 2 O 4 , and CoFe 2 O 4 by using novel microwave-Hydrothermal Processing. Nanophase ferrites with high surface areas, in the range of 72-247m 2 /g, have been synthesized in a matter of a few minutes at temperatures as low as 164°C. The rapid synthesis of nanophase ferrites via an acceleration of reaction rates under microwave-Hydrothermal conditions is expected to lead to energy savings.
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microwave Hydrothermal Processing of bifeo3 and csal2po6
ChemInform, 1996Co-Authors: Sridhar Komarneni, Rustum Roy, V C Menon, F AingerAbstract:Microwave-Hydrothermal (M-H) Processing was compared with conventional-Hydrothermal (C-H) Processing in the crystallization of BiFeO3 and CsAl2PO6 phases. The presence of the microwave field led to accelerated kinetics of the crystallization of both these phases as detected by powder X-ray diffraction. The acceleration of reaction rates under microwave field is expected to lead to energy savings during ceramic Processing.
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microwave Hydrothermal Processing of layered anion exchangers
Journal of Materials Research, 1996Co-Authors: Sridhar Komarneni, Rustum RoyAbstract:We have compared the microwave-Hydrothermal (M-H) Processing with conventional Hydrothermal (C-H) Processing in the preparation of two layered anion exchangers, i.e., Mg3Al(OH)8NO3 · nH2O and Ni1-xZn2x(OH)2(CH3COO)2x · nH2O. Both these phases can be crystallized more rapidly (an order of magnitude) under M-H Processing compared to C-H Processing. The above layered mixed basic salt of Ni and Zn was found to exhibit very high selectivity for PO4= (Kd = 15,000). Its order of selectivity for various anions in the presence of 0.1 N NaC1 (ratio of C1- to anion in question is 100) increases as follows: PO4= ≫ SO4 = > NO3-.
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microwave Hydrothermal Processing of metal powders
Journal of Materials Research, 1995Co-Authors: Sridhar Komarneni, Rajyalakshmi Pidugu, Rustum RoyAbstract:Novel microwave-Hydrothermal Processing has been developed by us recently for the synthesis of a wide variety of ceramic powders. Herein, we report the use of microwave-Hydrothermal Processing to synthesize several metal powders such as Cu, Ni, Co, and Ag by reducing their corresponding metal salts or hydroxides with ethylene glycol. Metal powders have been produced extremely rapidly a (few minutes) by microwave catalysis. The kinetics of metal powder synthesis have been increased by at least an order of magnitude by microwave-Hydrothermal Processing compared to the conventional refluxing process in ethylene glycol at about 195 °C.
