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| Registros recuperados: 11 | |
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| MÉNDEZ,JONH J; RAMON,CANELA; TORRES,MERCÈ. |
| In the present study, a kinetic model for the biocatalytic synthesis of esters using Rhizopus oryzae resting cells is proposed. The kinetic study has been made in a range of 30-50 °C and atmospheric pressure. The Influence of operating variables, water content, pH, amount of mycelium was studied. Different values of temperature, initial mycelium concentration and acid/alcohol molar ratio were tested. Initial rates were estimated from the slope of the concentration of palmitic acid, or their corresponding ester at conversions of less than 10%, versus time and reported as mmol l-1 min -1. The values of kinetic constants were computed using the freeware program SIMFIT (http:\\www.simfit.man.ac.uk). |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bound lipase; Esterification; Fungal resting cells; Rhizopus oryzae; Palmitic acid; Propanol. |
| Ano: 2009 |
URL: http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0120-548X2009000100011 |
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| Rajendran,Aravindan; Palanisamy,Anbumathi; Thangavelu,Viruthagiri. |
| Lipases are one of the most important industrial biocatalyst which catalyzes the hydrolysis of lipids. It can also reverse the reaction at minimum water activity. Because of this pliable nature, it is widely exploited to catalyze the diverse bioconversion reactions, such as hydrolysis, esterification, interesterification, alcoholysis, acidolysis and aminolysis. The property to synthesize the esters from the fatty acids and glycerol promotes its use in various ester synthesis. The esters synthesized by lipase finds applications in numerous fields such as biodiesel production, resolution of the recemic drugs, fat and lipid modification, flavour synthesis, synthesis of enantiopure pharmaceuticals and nutraceuticals. It plays a crucial role in the food... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Lipase; Food applications; Ester; Esterification; Synthesis. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132009000100026 |
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| Palazzi,Emilio; Molinari,Francesco; Fabiano,Bruno; Pessoa Jr,Adalberto; Converti,Attilio. |
| A relatively complex network of reactions has been investigated, using as a network model the isothermal batch esterification of acetic acid with ethanol in n-heptane catalyzed by lyophilized mycelium of Aspergillus oryzae. The kinetic analysis was firstly carried out on the whole system, without any simplification, by means of the well-known integral method. Owing to the poor results obtained by this way, we developed an alternative approach, combining initial rates and integral analysis and reducing the number of empirical parameters to be determined by the use of equilibrium data. All the values of the parameters calculated according to this "composite" approach to kinetic analysis well correlate with experimental data. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aspergillus oryzae; Complex network; Enzyme reactions; Esterification; Organic solvent. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822011000100048 |
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| Loyola,Nelson; Pavéz,Paula; Lillo,Sergio. |
| The present study extracted pectin from Pink Lady apples (Malus pumila), which present at physiological maturity an average 50% of red-color coverage, to assess whether this variety is characterized by a high (HM) or low methoxyl value (LM). The raw materials were obtained from the Marengo farm, Los Niches, Curicó province, in the south-central region of Chile. Acid hydrolysis was used and the material was then subjected to sensory analysis, evaluating the organoleptic characteristics of pectin. The pectin was extracted with citric acid, which was tested under three pH conditions (2.5, 3.0 and 3.5, the latter corresponding to the natural pH of apples) for 60 and 90 min and subjected to a constant temperature of 90 °C. The degree of esterification (DE) of... |
| Tipo: Journal article |
Palavras-chave: Apple; Pectin; Esterification; Sensory analysis. |
| Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202011000300012 |
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| Mat Radzi,Salina; Basri,Mahiran; Bakar Salleh,Abu; Ariff,Arbakariya; Mohammad,Rosfarizan; Abdul Rahman,Mohd. Basyaruddin; Abdul Rahman,Raja Noor Zaliha Raja. |
| High performance enzymatic synthesis of oleyl oleate, a liquid wax ester was carried out by lipase-catalysed esterification of oleic acid and oleyl alcohol. Various reaction parameters were optimised to obtain high yield of oleyl oleate. The optimum condition to produce oleyl oleate was reaction time; 5 min, organic solvents of log P ≥ 3.5, temperature; 40-50ºC, amount of enzyme; 0.2-0.4 g and molar ratio of oleyl alcohol to oleic acid; 2:1. The operational stability of enzyme was maintained at >90% yield up to 9 cycles. Analysis of the yield of the product showed that at optimum conditions, >95% liquid wax esters were produced |
| Tipo: Journal article |
Palavras-chave: Oleyl oleate; Immobilised lipase; Esterification; Liquid wax ester. |
| Ano: 2005 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582005000300009 |
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| Nawani,Neerupma; Singh,Rajvinder; Kaur,Jagdeep. |
| A thermostable lipase was partially purified from the culture supernatant of a thermophilic Bacillus sp. The enzyme is optimally active at 60ºC and pH 8.0. The enzyme showed enhancement in activity in presence of benzene or hexane (30% v/v each). The activity (assayed by determining the release of pNP from pNP laurate) was stimulated up to 60% of these solvents in enzyme reaction mixture. The catalytic properties of this thermostable enzyme can be further improved via the use of different immobilization techniques and reaction conditions. Enzyme was immobilized on different solid supports and their enzyme activity and stability was compared. The enzyme was adsorbed on silica and HP-20 beads followed by cross-linking with gluteraldehyde on HP-20,... |
| Tipo: Journal article |
Palavras-chave: Esterification; Immobilization; Lipase; Thermostability. |
| Ano: 2006 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582006000500011 |
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| Registros recuperados: 11 | |
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