共查询到20条相似文献,搜索用时 15 毫秒
1.
Paroul N Grzegozeski LP Chiaradia V Treichel H Cansian RL Oliveira JV de Oliveira D 《Bioprocess and biosystems engineering》2011,34(3):331-337
This study reports the maximization of geranyl oleate production by esterification of geraniol and oleic acid in a solvent-free system using a commercial lipase as catalyst. The operating conditions that maximized geranyl oleate production were determined to be 40?°C, geraniol to oleic acid molar ratio of 5:1, 150?rpm and 10?wt% of enzyme, with a resulting reaction conversion of about 93%. After determining the best reaction parameters, a kinetic study was performed and the results obtained in this step allow to conclude that an excess of alcohol (alcohol to acid molar ratio of 5:1), relatively low enzyme concentration (5?wt%) and temperature of 50?°C afforded nearly complete reaction conversion after 1?h of reaction. New experimental data on enzymatic esterification of geraniol and oleic acid for geranyl oleate production are reported in this work, showing a promising perspective of the technique to overcome the inconvenience of the chemical-catalyzed route. 相似文献
2.
Aline Richetti Selma G. F. Leite Octávio A. C. Antunes Lindomar A. Lerin Rogério M. Dallago Daniel Emmerich Marco Di Luccio J. Vladimir Oliveira Helen Treichel Débora de Oliveira 《Bioprocess and biosystems engineering》2010,33(3):331-337
This work reports the optimization of 2-ethylhexyl palmitate production by esterification reaction in a solvent-free system
using a commercial lipase as catalyst. For this, a sequential strategy was performed applying three experimental designs.
An empirical model was built so as to assess the effects of process variables on the reaction conversion. Afterward, the operating
conditions that optimized 2-ethylhexyl palmitate production were determined to be acid to alcohol molar ratio of 1:5.5, 70 °C,
150 rpm and 10.5 wt% of enzyme, leading to a reaction conversion as high as 93%. From this point, a kinetic study was carried
out evaluating the influence of acid to alcohol molar ratio, enzyme concentration and temperature on product yield. Results
obtained in this step allow to conclude that an excess of alcohol (acid to alcohol molar ratio of 1:6), relatively low enzyme
concentration (10 wt%) and temperature of 70 °C led to nearly complete reaction conversion. 相似文献
3.
Natália Paroul Adriana Biasi Ane Cheila Rovani Camile Prigol Rogerio Dallago Helen Treichel Rogério L. Cansian J. Vladimir Oliveira Débora de Oliveira 《Bioprocess and biosystems engineering》2010,33(5):583-589
This work investigated the influence of temperature, enzyme concentration, substrates molar ratio, in the absence and presence
of organic solvent, at two molar ratios of the substrates on the enzymatic production of linalil esters using the immobilized
lipase Novozym 435 as catalyst, different acids and linalool and Ho-Sho essential oil as substrates. The best reaction conversion
was obtained at the highest temperature (70 °C), for both solvent free (3.81%) and with solvent addition (2.25%), for a solvent
to substrates molar ratio of 2:1, enzyme concentration of 5 wt% and acid to alcohol molar ratio of 1:1. The reaction kinetics
revealed that Ho-Sho essential oil afforded the greatest conversions when compared with pure linalool. Higher linalil esters
production were achieved after 10 h reaction (5.58%) in 2:1 solvent to substrates molar ratio, with enzyme concentration of
5 wt%, at 70 °C and anhydride to alcohol molar ratio of 1:1 using Ho-Sho essential oil as substrate. 相似文献
4.
Nakagawa H. Watanabe S. Shimura S. Kirimura K. Usami S. 《World journal of microbiology & biotechnology》1997,14(2):219-222
Enzymatic synthesis of terpenyl esters by esterification or transesterification with fatty acid vinyl esters as acyl donors by celite-adsorbed lipase of Trichosporon fermentans was investigated. In direct esterification of geraniol, the lipase showed high reactivity toward fatty acids with carbon chains longer than C-8, but little reactivity toward fatty acids with shorter chains. With fatty acid vinyl esters as acyl donors, the lipase catalysed the synthesis of geranyl and citronellyl esters with carbon chains shorter than C-6 in with yields of >90% molar conversion. Time course, effects of added water, temperature and substrate concentration were studied for the synthesis of geranyl acetate. Molar conversion yield reached 97.5% after 5 h incubation at 30–40°C with the addition of 3% water. In this reaction, no inhibition by substrates such as geraniol and vinyl acetate was observed. 相似文献
5.
《Journal of Molecular Catalysis .B, Enzymatic》2011,69(3-4):230-239
The Talaromyces thermophilus lipase (TTL) was immobilized by different methods namely adsorption, ionic binding and covalent coupling, using various carriers. Chitosan, pre-treated with glutaraldehyde, was selected as the most suitable support material preserving the catalytic activity almost intact and offering maximum immobilization capacity (76% and 91%, respectively). The chitosan-immobilized lipase could be reputably used for ten cycles with more than 80% of its initial hydrolytic activity. Shift in the optimal temperature from 50 to 60 °C and in the pH from 9.5 to 10, were observed for the immobilized lipase when compared to the free enzyme.The catalytic esterification of oleic acid with 1-butanol has been carried out using hexane as organic solvent. A high performance synthesis of 1-butyl oleate was obtained (95% of conversion yield) at 60 °C with a molar ratio of 1:1 oleic acid to butanol and using 100 U (0.2 g) of immobilized lipase. The esterification product is analysed by GC/MS to confirm the conversion percentage calculated by titration. 相似文献
6.
H. Nakagawa S. Watanabe S. Shimura K. Kirimura S. Usami 《World journal of microbiology & biotechnology》1998,14(2):219-222
Enzymatic synthesis of terpenyl esters by esterification or transesterification with fatty acid vinyl esters as acyl donors by celite-adsorbed lipase of Trichosporon fermentans was investigated. In direct esterification of geraniol, the lipase showed high reactivity toward fatty acids with carbon chains longer than C-8, but little reactivity toward fatty acids with shorter chains. With fatty acid vinyl esters as acyl donors, the lipase catalysed the synthesis of geranyl and citronellyl esters with carbon chains shorter than C-6 in with yields of >90% molar conversion. Time course, effects of added water, temperature and substrate concentration were studied for the synthesis of geranyl acetate. Molar conversion yield reached 97.5% after 5 h incubation at 30–40°C with the addition of 3% water. In this reaction, no inhibition by substrates such as geraniol and vinyl acetate was observed. 相似文献
7.
In view of several disadvantages as well as adverse effects associated with the use of chemical processes for producing esters, alternative techniques such as the utilization of enzymes on multi-walled carbon nanotubes (MWCNTs), have been suggested. In this study, the oxidative MWCNTs prepared using a mixture of HNO3 and H2SO4 (1:3 v/v) were used as a supportive material for the immobilization of Candida rugosa lipase (CRL) through physical adsorption process. The resulting CRL-MWCNTs biocatalysts were utilized for synthesizing geranyl propionate, an important ester for flavoring agent as well as in fragrances. Enzymatic esterification of geraniol with propionic acid was carried out using heptane as a solvent and the efficiency of CRL-MWCNTs as a biocatalyst was compared with the free CRL, considering the incubation time, temperature, molar ratio of acid:alcohol, presence of desiccant as well as its reusability. It was found that the CRL-MWCNTs resulted in a 2-fold improvement in the percentage of conversion of geranyl propionate when compared with the free CRL, demonstrating the highest yield of geranyl propionate at 6 h at 55 °C, molar ratio acid: alcohol of 1:5 and with the presence of 1.0 g desiccant. It was evident that the CRL-MWCNTs biocatalyst could be reused for up to 6 times before a 50% reduction in catalytic efficiency was observed. Hence, it appears that the facile physical adsorption of CRL onto F-MWCNTs has improved the activity and stability of CRL as well as served as an alternative method for the synthesis of geranyl propionate. 相似文献
8.
Hong-de Yan Zhao Wang Ling-jie Chen 《Journal of industrial microbiology & biotechnology》2009,36(5):643-648
Kinetic resolution of α-lipoic acid, a case of remote stereocenter discrimination, was accomplished using lipase from Aspergillus oryzae WZ007. Performance of this lipase was investigated for enantioselective esterification of (S)-α-lipoic acid, leaving the target product (R)-α-lipoic acid in unreacted form. The effects of chain length of alcohol, type of solvent, molar ratio of alcohol:acid, and
reaction temperature were studied. The optimum reaction conditions were found to be esterification with n-octanol at 50°C in heptane with an alcohol:acid molar ratio of 5:1. The conversion rate of α-lipoic acid was 75.2%, with
an enantiomeric excess of 92.5% towards unreacted substrate in a reaction time of 48 h. 相似文献
9.
We successfully developed an efficient and promising bioprocess for 1,3-diolein synthesis by performing Novozym 435-mediated esterification of oleic acid with monoolein in this work. Under the optimized conditions (60 °C, molar ratio of oleic acid to monoolein 1.2:1), a 1,3-diolein yield of 93.7% could be achieved, and the yield of 1,2-diolien was low (2.6%). The high yield of 1,3-diolein and the optimum reaction time were improved remarkably compared with the results of our previous study, which involved the enzymatic esterification of oleic acid with glycerol. An additional advantage of the new process is the fact that 90% original activity of the enzyme was maintained after being used for 100 reactions. The present work could be seen as a useful enzyme-catalyzed process for the industrial production of 1,3-diacylglycerol. 相似文献
10.
Nishat R. Khan 《Biocatalysis and Biotransformation》2020,38(2):114-122
AbstractA cosmetic ester, cetyl oleate was synthesized using microwave irradiated system. The esterification reaction was carried using Candida antarctica lipase B in a solvent-free media. The influence of various reaction parameters was studied, and the efficiency of Fermase CALBTM10000 was compared with other enzymes. Equilibrium conversion of 97.5% was obtained within 20?min at 60?°C temperature, 1:2 oleic acid to cetyl alcohol molar ratio and 4% w/w dose of lipase. A comparative study showed that microwave irradiation is a much more efficient method than ultrasound irradiation and conventional heating. Fermase CALBTM10000 was reusable over 6 enzymatic cycles as its stability improved under microwave system. Physicochemical parameters of cetyl oleate were tested in order to analyze its suitability for further cosmetic use. 相似文献
11.
Abdul Rahman Mohd Basyaruddin Jarmi Nor Izuan Chaibakhsh Naz Basri Mahiran 《Journal of industrial microbiology & biotechnology》2011,38(1):229-234
Esterification of succinic acid with oleyl alcohol catalyzed by immobilized Candida antarctica lipase B (Novozym 435) was investigated in this study. Response surface methodology (RSM) based on a five-level, four-variable
central composite design (CCD) was used to model and analyze the reaction. A total of 21 experiments representing different
combinations of the four parameters including temperature (35–65°C), time (30–450 min), enzyme amount (20-400 mg), and alcohol:acid
molar ratio (1:1-8:1) were generated. A partial cubic equation could accurately model the response surface with a R2 of 0.9853. The effect and interactions of the variables on the ester synthesis were also studied. Temperature was found to
be the most significant parameter that influenced the succinate ester synthesis. At the optimal conditions of 41.1°C, 272.8 min,
20 mg enzyme amount and 7.8:1 alcohol:acid molar ratio, the esterification percentage was 85.0%. The model can present a rapid
means for estimating the conversion yield of succinate ester within the selected ranges. 相似文献
12.
Commercial lipase preparations and mycelium bound lipase from Aspergillus niger NCIM 1207 were used for esterification of acetic acid with isoamyl alcohol to obtain isoamyl acetate. The esterification
reaction was carried out at 30°C in n-hexane with shaking at 120 rpm. Initial reaction rates, conversion efficiency and isoamyl acetate concentration obtained
using Novozyme 435 were the highest. Mycelium bound lipase of A. niger NCIM 1207 produced maximal isoamyl acetate formation at an alcohol/acid ratio of 1.6. Acetic acid at higher concentrations
than required for the critical alcohol/acid ratio lower than 1.3 and higher than 1.6 resulted in decreased yields of isoamyl
acetate probably owing to lowering of micro-aqueous environmental pH around the enzyme leading to inhibition of enzyme activity.
Mycelium bound A. niger lipase produced 80 g/l of isoamyl acetate within 96 h even though extremely less amount of enzyme activity was used for esterification.
The presence of sodium sulphate during esterification reaction at higher substrate concentration resulted in increased conversion
efficiency when we used mycelium bound enzyme preparations of A. niger NCIM 1207. This could be due to removal of excess water released during esterification reaction by sodium sulphate. High
ester concentration (286.5 g/l) and conversion (73.5%) were obtained within 24 h using Novozyme 435 under these conditions. 相似文献
13.
Biodiesel is increasingly perceived as an important component of solutions to the important current issues of fossil fuel
shortages and environmental pollution. Utilization of soluble lipase offers an alternative approach to lipase-catalyzed biodiesel
production using immobilized enzyme or whole-cell catalysis. Soluble lipase NS81020, produced by submerged fermentation of
genetically modified Aspergillus oryzae microorganism, was first proposed here as the catalyst of biodiesel preparation with oleic acid in the biphasic aqueous-oil
systems. The effect factors such as enzyme concentration, water content, temperature, molar ratio of methanol to oil, stirring
rate and pH of buffer solution on the esterification rate were investigated systematically. The reaction time could be shortened
with the increasing of enzyme concentration as long as the maximum enzyme absorptive capacity on the interface in the biphasic
aqueous-oil systems was not achieved. The optimal water content in the biphasic aqueous-oil systems was 10 wt% by oleic acid
weight. The reaction rate was enhanced with the increasing molar ratio of methanol to oil, the increasing stirring rate or
the decreasing temperature. Although soluble lipase NS81020 had lower activity at pH 10.55, hydroxyl ion conduced to restrain
hydrolysis of methyl ester and facilitated the reaction toward the methyl ester formation. 相似文献
14.
Geraniol esters were synthesised by direct esterification catalysed by esterases and lipases (five enzymes were tested) in a solvent-free system at 37°C. The best conversions yields, about 85%, on geranyl butyrate and valerate obtained with esterase 30 000 from Mucor miehei. The effect of substrate molar ratio alcohol/acid variation was studied. A study of the water production was made in parallel during the esterification reaction. 相似文献
15.
Optimized enzymatic synthesis of geranyl butyrate with lipase AY from Candida rugosa 总被引:5,自引:0,他引:5
Response surface methodology (RSM) and five-level, five-variable central composite rotatable design (CCRD) were used to evaluate the effects of synthetic variables, such as reaction time (1-9 h), temperature (25-65 degrees C), enzyme amount (10-50%), substrate molar ratio of geraniol to tributyrin (1:0.33-1:1), and added water amount (0-20%) on molar percent yield of geranyl butyrate, using lipase AY from Candida rugosa. Reaction time and temperature were the most important variables and substrate molar ratio had no effect on percent molar conversion. Based on contour plots, optimum conditions were: reaction time 9 h, temperature 35 degrees C, enzyme amount 50%, substrate molar ratio 1:0.33, and added water 10%. The predicted value was 100% and actual experimental value was 96.8% molar conversion. (c) 1996 John Wiley & Sons, Inc. 相似文献
16.
Khairulazhar Jumbri Mohd Fahruddin Al-Haniff Rozy Siti Efliza Ashari Rosfarizan Mohamad Mahiran Basri Hamid Reza Fard Masoumi 《PloS one》2015,10(12)
Kojic acid is widely used to inhibit the browning effect of tyrosinase in cosmetic and food industries. In this work, synthesis of kojic monooleate ester (KMO) was carried out using lipase-catalysed esterification of kojic acid and oleic acid in a solvent-free system. Response Surface Methodology (RSM) based on central composite rotatable design (CCRD) was used to optimise the main important reaction variables, such as enzyme amount, reaction temperature, substrate molar ratio, and reaction time along with immobilised lipase from Candida Antarctica (Novozym 435) as a biocatalyst. The RSM data indicated that the reaction temperature was less significant in comparison to other factors for the production of a KMO ester. By using this statistical analysis, a quadratic model was developed in order to correlate the preparation variable to the response (reaction yield). The optimum conditions for the enzymatic synthesis of KMO were as follows: an enzyme amount of 2.0 wt%, reaction temperature of 83.69°C, substrate molar ratio of 1:2.37 (mmole kojic acid:oleic acid) and a reaction time of 300.0 min. Under these conditions, the actual yield percentage obtained was 42.09%, which is comparably well with the maximum predicted value of 44.46%. Under the optimal conditions, Novozym 435 could be reused for 5 cycles for KMO production percentage yield of at least 40%. The results demonstrated that statistical analysis using RSM can be used efficiently to optimise the production of a KMO ester. Moreover, the optimum conditions obtained can be applied to scale-up the process and minimise the cost. 相似文献
17.
Laudani CG Habulin M Primozic M Knez Z Della Porta G Reverchon E 《Bioprocess and biosystems engineering》2006,29(2):119-127
Octyl oleate is a useful organic compound with several applications in cosmetic, lubricant and pharmaceutical industry. At first, the enzymatic synthesis of n-octyl oleate by direct lipase-catalysed esterification of oleic acid and 1-octanol was investigated in a stirred batch reactor in solvent-free system. A systematic screening and optimisation of the reaction parameters were performed to gain insight into the kinetics mechanism. Particularly, enzyme concentration, reaction temperature, stirrer speed, water content, substrates concentration and molar ratio were optimised with respect to the final product concentration and reaction rate. The kinetics mechanism of the reaction was investigated. Finally, a comparison of the experimental results obtained in a solvent free-system with those using two different solvents, supercritical carbon dioxide (SC-CO2) and n-hexane, was proposed. It resulted that in SC-CO2 higher concentration of the desired product was attained, requiring lower enzyme concentrations to achieve comparable conversion of free fatty acid into fatty acid ester. 相似文献
18.
S.-W. Chang C.-J. Yang F.-Y. Chen C.C. Akoh C.-J. Shieh 《Journal of Molecular Catalysis .B, Enzymatic》2009,56(1):7-12
l-Ascorbyl laurate is a fatty acid derivative of l-ascorbic acid which can be widely used as a natural antioxidant in both lipid containing food and cosmetic applications. To avoid any possible harmful effects from chemically synthesized product, the enzymatic synthesis appears to be the best way to satisfy the consumer demand for natural antioxidants. The ability of immobilized lipase from Candida antarctica (Novozym® 435) to catalyze the direct esterification between l-ascorbic acid and lauric acid was investigated. Response surface methodology (RSM) and 5-level-4-factor central composite rotatable design (CCRD) were employed to evaluate the effects of synthesis parameters, such as reaction time (2–10 h), temperature (25–65 °C), enzyme amount (10–50% w/w of l-ascorbic acid), and substrate molar ratio of l-ascorbic acid to lauric acid (1:1–1:5) on percentage molar conversion to l-ascorbyl laurate. Based on the analysis result of ridge max, the optimal enzymatic synthesis conditions were predicted as follows: reaction time 6.7 h, temperature 30.6 °C, enzyme amount 34.5%, substrate molar ratio 1:4.3; and the optimal actual yield was 93.2%. 相似文献
19.
《Journal of Molecular Catalysis .B, Enzymatic》2011,73(3-4):157-162
Esterification of glycerol and oleic acid catalyzed by lipase Candida sp. 99-125 was carried out to synthesize monoglyceride (MAG) and diglyceride (DAG) in solvent-free system. Beta-cyclodextrin as an assistant was mixed with the lipase powder. Six reaction variables, initial water content (0–14 wt% of the substrate mass), the glycerol/oleic acid molar ratio (1:1–6:1), catalyst load (3–15 wt% of the substrate mass), reaction temperature (30–60 °C), agitator speed (130–250 r/min) and beta-cyclodextrin/lipase mass ratio (0–2) were optimized. The optimal conditions to the synthesis of MAG and DAG were different: the optimal glycerol/oleic acid molar ratio, beta-cyclodextrin/lipase mass ratio, catalyst load and reaction temperature were 6:1, 0, 5%, 50 °C for MAG, and 5:1, 1.5, 10%, 40 °C for DAG, respectively. The optimal water content and agitator speed for both MAG and DAG were 10% and 190 r/min, respectively. Under the optimal conditions, 49.6% MAG and 54.3% DAG were obtained after 8 h and 4 h, respectively, and the maximum of 81.4% MAG plus DAG (28.1% MAG and 53.3% DAG) was obtained after 2 h under the DAG optimal condition. Above 90% purity of MAG and DAG can be obtained by silica column separation. 相似文献
20.
Paramita Mahapatra Annapurna Kumari Garalapati V. Kumar Ahindra Nag 《Biocatalysis and Biotransformation》2013,31(2):124-130
The objective of the present work was to study the kinetics of the solvent-free synthesis of geranyl acetate by a novel lipase (activity 60 U g?1) made by immobilization of lipase from Rhizopus oligosporous NRRL 5905 on to cross-linked silica gel. Transesterification was performed with vinyl acetate as the acyl donor. Vinyl acetate was used in large excess compared to geraniol, which made the reaction pseudo first order with respect to geraniol and the reaction rate followed Michaelis–Menten kinetics for a single substrate. To obtain the highest yield for geranyl acetate, various relevant physical parameters such as shaking speed, reaction time, enzyme concentration, initial water amount and reaction temperature that influence the activity of lipase were investigated. A maximum molar conversion of 67% was achieved after 48 h of reaction at 30°C, at an enzyme concentration of 25% w/v of reaction mixture. Substrate conversion remained constant for five successive cycles; thereafter the conversion dropped by only 11%. Using a pseudo first-order kinetic model for geranyl acetate synthesis in the absence of organic solvents, apparent Km and Vmax values were evaluated as 60 mM and 141 µmol g?1 h?1, respectively. 相似文献