Modelling the production of ethyl butyrate catalysed by Candida rugosa lipase immobilised in polyuretane foams

Response surface methodology was used to model and optimise the esterification of ethanol with butyric acid in n-hexane, catalysed by Candida rugosa lipase immobilised in two hydrophilic polyurethane foams (“FHP 2002TM” and “FHP 5000TM”). Experiments were carried out following central composite rotatable designs (CCRD), as a function of the initial water activity of the biocatalyst (aw), initial butyric acid concentration (A) and ethanol:acid molar ratio (MR) in the organic medium. Ester production increased with increasing aw of the biocatalysts, probably due to the hydrophilicity of both substrates in contrast with the hydrophobicity of the product, which is released to the bulk medium. Thus, for each biocatalyst (aw = 0.98) another CCRD was performed as a function of A and MR. With both preparations, higher conversions (>95%) were observed for low A values. For the “FHP 2002TM” system, a maximum ester production of 0.23M is expected, after 18-h reaction, at initial 0.35M A and 1.51 MR, corresponding to aw of 0.95 and 0.84MA and 1.65Methanol in lipase microenvironment.With “FHP 5000TM” system, predicted initial conditions of 0.54M A and 0.75 MR (0.32M A; 0.75M ethanol in microenvironment; aw of 0.95), will lead to the maximum ester production of 0.27 M. These maxima were experimentally confirme

Crescimento e produtividade de duas cultivares de feijão em função de doses de ácido 2,3,5-triiodobenzoico

RESUMO: O crescimento excessivo da parte aérea do feijoeiro pode aumentar o acamamento das plantas e promover fechamento muito rápido da cultura, limitando a produtividade de grãos. O uso de reguladores de crescimento, como o ácido 2,3,5-triiodobenzoico (TIBA), pode reduzir o crescimento das plantas, porém, não existem informações sobre o uso dessa tecnologia na cultura do feijão. Objetivou-se com este trabalho avaliar o efeito de doses de TIBA (0, 8, 16, 32, 64 e 128g do i.a. ha-1) sobre o crescimento e a produtividade de grãos de duas cultivares de feijão ('IAC Alvorada' e 'IAC Jabola'). O delineamento experimental foi o de blocos ao acaso, em esquema de parcelas subdivididas, com quatro repetições. A aplicação de TIBA reduziu o comprimento da maior haste de ambas as cultivares, até a dose média estimada de 100g ha-1 de TIBA. A altura de inserção da primeira vagem foi reduzida apenas na cultivar IAC Alvorada até a dose de 88g ha-1 de TIBA. A aplicação de TIBA reduziu em 10% o número de grãos por vagem. A utilização de TIBA não afetou a produtividade de grãos, sendo uma alternativa para diminuir o porte das plantas de feijão

Modelling the production of ethyl butyrate catalysed by Candida rugosa lipase immobilised in polyuretane foams

Response surface methodology was used to model and optimise the esterification of ethanol with butyric acid in n-hexane, catalysed by Candida rugosa lipase immobilised in two hydrophilic polyurethane foams (“FHP 2002TM” and “FHP 5000TM”). Experiments were carried out following central composite rotatable designs (CCRD), as a function of the initial water activity of the biocatalyst (aw), initial butyric acid concentration (A) and ethanol:acid molar ratio (MR) in the organic medium. Ester production increased with increasing aw of the biocatalysts, probably due to the hydrophilicity of both substrates in contrast with the hydrophobicity of the product, which is released to the bulk medium. Thus, for each biocatalyst (aw = 0.98) another CCRD was performed as a function of A and MR. With both preparations, higher conversions (>95%) were observed for low A values. For the “FHP 2002TM” system, a maximum ester production of 0.23M is expected, after 18-h reaction, at initial 0.35M A and 1.51 MR, corresponding to aw of 0.95 and 0.84MA and 1.65Methanol in lipase microenvironment.With “FHP 5000TM” system, predicted initial conditions of 0.54M A and 0.75 MR (0.32M A; 0.75M ethanol in microenvironment; aw of 0.95), will lead to the maximum ester production of 0.27 M. These maxima were experimentally confirme

Modelling the production of ethyl butyrate catalysed by Candida rugosa lipase immobilised in polyuretane foams

Response surface methodology was used to model and optimise the esterification of ethanol with butyric acid in n-hexane, catalysed by Candida rugosa lipase immobilised in two hydrophilic polyurethane foams (“FHP 2002TM” and “FHP 5000TM”). Experiments were carried out following central composite rotatable designs (CCRD), as a function of the initial water activity of the biocatalyst (aw), initial butyric acid concentration (A) and ethanol:acid molar ratio (MR) in the organic medium. Ester production increased with increasing aw of the biocatalysts, probably due to the hydrophilicity of both substrates in contrast with the hydrophobicity of the product, which is released to the bulk medium. Thus, for each biocatalyst (aw = 0.98) another CCRD was performed as a function of A and MR. With both preparations, higher conversions (>95%) were observed for low A values. For the “FHP 2002TM” system, a maximum ester production of 0.23M is expected, after 18-h reaction, at initial 0.35M A and 1.51 MR, corresponding to aw of 0.95 and 0.84MA and 1.65Methanol in lipase microenvironment.With “FHP 5000TM” system, predicted initial conditions of 0.54M A and 0.75 MR (0.32M A; 0.75M ethanol in microenvironment; aw of 0.95), will lead to the maximum ester production of 0.27 M. These maxima were experimentally confirme

Interesterification of fat blends rich in omega-3 polyunsaturated fatty acids catalysed by immobilized Thermomyces lanuginosa lipase under high pressure

The interesterification of natural fats will improve certain physical and nutraceutical properties by modification of their acylglycerol profile. In this study, the effect of high pressure in the interesterification kinetics of fat blends, in solvent-free medium, catalysed by a commercial immobilized lipase from Thermomyces lanuginosa was evaluated. Reaction media were ternary blends of palm stearin, palm kernel oil and a concentrate of triacylglycerols (TAG) rich in -3 polyunsaturated fatty acids. Reactions were carried out at 60 ◦C, at 0.1, 50, 100 and 150MPa. The interesterification was followed (i) by the decrease in “Solid Fat Content” values of the blend at 35 ◦C (SFC35 ◦C) and (ii) by the changes in the acylglycerol profile. The biocatalyst presented interesterification activity at least up to 150MPa. Results obtained at 0.1MPa, with no agitation of the reaction medium, were found to be similar to those obtained under high-pressure conditions. The observed decrease in SFC35 ◦C values was accompanied by important changes in the acylglycerol profile. An increase in compounds of low equivalent carbon number (ECN) and in TAG of ECN 44 and 46 were observed. This increase was accompanied by a consumption of TAG of ECN 48 and 50 for all pressure values, and also of trilaurin (ECN = 36) at normal pressure. High pressures seem to affect lipase selectivity towards lauric acid. Batch operational stability tests showed a linear inactivation profile for each pressure. Half-lives of about 15, 6 and 4 h were estimated for the biocatalyst under 0.1, 50 and 150MPa, respectivel

Interesterification of fat blends rich in omega-3 polyunsaturated fatty acids catalysed by immobilized Thermomyces lanuginosa lipase under high pressure

The interesterification of natural fats will improve certain physical and nutraceutical properties by modification of their acylglycerol profile. In this study, the effect of high pressure in the interesterification kinetics of fat blends, in solvent-free medium, catalysed by a commercial immobilized lipase from Thermomyces lanuginosa was evaluated. Reaction media were ternary blends of palm stearin, palm kernel oil and a concentrate of triacylglycerols (TAG) rich in -3 polyunsaturated fatty acids. Reactions were carried out at 60 ◦C, at 0.1, 50, 100 and 150MPa. The interesterification was followed (i) by the decrease in “Solid Fat Content” values of the blend at 35 ◦C (SFC35 ◦C) and (ii) by the changes in the acylglycerol profile. The biocatalyst presented interesterification activity at least up to 150MPa. Results obtained at 0.1MPa, with no agitation of the reaction medium, were found to be similar to those obtained under high-pressure conditions. The observed decrease in SFC35 ◦C values was accompanied by important changes in the acylglycerol profile. An increase in compounds of low equivalent carbon number (ECN) and in TAG of ECN 44 and 46 were observed. This increase was accompanied by a consumption of TAG of ECN 48 and 50 for all pressure values, and also of trilaurin (ECN = 36) at normal pressure. High pressures seem to affect lipase selectivity towards lauric acid. Batch operational stability tests showed a linear inactivation profile for each pressure. Half-lives of about 15, 6 and 4 h were estimated for the biocatalyst under 0.1, 50 and 150MPa, respectivel

Synthesis of ethyl butyrate in organic media catalized by Candida rugosa lipase immobilized in polyurethane foams: a kinetic study

A kinetic study on the synthesis of ethyl butyrate in n-hexane, catalyzed by Candida rugosa lipase immobilized in two hydrophilic polyurethane foams (“HYPOL FHP 2002” and “HYPOL FHP 5000”)was performed. With the “FHP5000” foams, esterification rates and conversion were always higher than those obtained with “FHP2002”. For both immobilized preparations, BA did not cause any inhibition on the enzymatic activity, in the range of concentration tested (0.078–0.7M) at an initial ethanol concentration of 0.105M. Michäelis–Menten kinetics was observed: a plateau being reached at the initial bulk BA concentration of 0.40Mand 0.45 M, corresponding to microenvironmental concentrations of 0.851Mand 0.329 M, respectively with the lipase in “FHP2002” and “FHP5000” foams. Inhibition by EtOH was observed for initial bulk concentrations higher than 0.15 M, corresponding to microenvironmental concentrations of 0.426M and 0.256 M, for the lipase in “FHP2002” and “FHP5000” foams, respectively. Kinetic data could be well described by the substrate-inhibition model, considering the initial bulk or microenvironmental ethanol concentrations as inhibitor

Synthesis of ethyl butyrate in organic media catalized by Candida rugosa lipase immobilized in polyurethane foams: a kinetic study

A kinetic study on the synthesis of ethyl butyrate in n-hexane, catalyzed by Candida rugosa lipase immobilized in two hydrophilic polyurethane foams (“HYPOL FHP 2002” and “HYPOL FHP 5000”)was performed. With the “FHP5000” foams, esterification rates and conversion were always higher than those obtained with “FHP2002”. For both immobilized preparations, BA did not cause any inhibition on the enzymatic activity, in the range of concentration tested (0.078–0.7M) at an initial ethanol concentration of 0.105M. Michäelis–Menten kinetics was observed: a plateau being reached at the initial bulk BA concentration of 0.40Mand 0.45 M, corresponding to microenvironmental concentrations of 0.851Mand 0.329 M, respectively with the lipase in “FHP2002” and “FHP5000” foams. Inhibition by EtOH was observed for initial bulk concentrations higher than 0.15 M, corresponding to microenvironmental concentrations of 0.426M and 0.256 M, for the lipase in “FHP2002” and “FHP5000” foams, respectively. Kinetic data could be well described by the substrate-inhibition model, considering the initial bulk or microenvironmental ethanol concentrations as inhibitor