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1.
Abstract

In present study involving castor oil hydrolysis catalyzed by porcine pancreas lipase, organic solvent, and ionic liquid were applied to augment production of ricinoleic acid. Toluene was the best organic solvent (30.18% hydrolysis in 2?h). In presence of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), an ionic liquid, the optimal conditions were, 0.12?g ionic liquid/g oil, 4?mg enzyme/g oil, 2?g buffer/g oil, pH of 8, and 2.5?h. Under this condition, ricinoleic acid recovery was 43.41 and 52% at 25?°C and 35?°C, respectively. Organic solvent concentration, enzyme concentration, buffer concentration and time had significant impacts on lipase catalyzed hydrolysis in the presence of organic liquid; whereas, pH and speed remained insignificant. In hydrolysis involving ionic liquid, time had most important effect on ricinoleic acid production. Interaction between enzyme and buffer concentration was most significant. Interactions of ionic liquid concentration with all other variables were also significant besides buffer concentration–time interaction.  相似文献   

2.
γ-Linolenic acid (GLA) has the physiological functions of modulating immune and inflammatory responses. We produced structured TAG rich in 1,3-dicapryloyl-2-γ-linolenoyl glycerol (CGC) from GLA-rich oil (GLA45 oil; GLA content, 45.4 wt%), which was prepared by hydrolysis of borage oil with Candida rugosa lipase having weak activity on GLA. A mixture of GLA45 oil/caprylic acid (CA) (1∶2, w/w) was continuously fed into a fixed-bed bioreactor (18×180 mm) packed with 15 g immobilized Rhizopus oryzae lipase at 30°C, and a flow rate of 4 g/h. The acidolysis proceeded efficiently, and a significant decrease of lipase activity was not observed in full-time operation for 1 mon. GLA45 oil contained 10.2 mol% MAG and 27.2 mol% DAG. However, the reaction converted the partial acylglycerols to structured TAG and tricaprylin and produced 44.5 mol% CGC based on the content of total acylglycerols. Not only FFA in the reaction mixture but also part of the tricaprylin and partial acylglycerols were removed by molecular distillation. The distillation resulted in an increase of the CGC content in the purified product to 52.6 mol%. The results showed that CGC-rich structured TAG can efficiently be produced by a two-step process comprising selective hydrolysis of borage oil using C. rugosa lipase (first step) and acidolysis of the resulting GLA-rich oil with CA using immobilized R. oryzae lipase (second step).  相似文献   

3.
A new assay was designed to measure the release of omega-3 acids [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] from the hydrolysis of sardine oil by lipases immobilized inside porous supports. A biphasic system was used containing the fish oil dissolved in the organic phase and the immobilized lipase suspended in the aqueous phase. The assay was optimized by using a very active derivative of Rhizomucor miehei lipase (RML) adsorbed onto octyl-Sepharose. Standard reaction conditions were: (a) an organic phase composed by 30/70 (v:v) of oil in cyclohexane, (b) an aqueous phase containing 50 mM methyl-cyclodextrin in 10 mM Tris buffer at pH 7.0. The whole reaction system was incubated at 25 °C. Under these conditions, up to 2% of the oil is partitioned into the aqueous phase and most of the 95% of released acids were partitioned into the organic phase. The organic phase was analyzed by RP-HPLC (UV detection at 215 nm) and even very low concentrations (e.g., 0.05 mM) of released omega-3 fatty acid could be detected with a precision higher than 99%. Three different lipases adsorbed on octyl-Sepharose were compared: Candida antarctica lipase-fraction B (CALB), Thermomyces lanuginosa lipase (TLL) and RML. The three enzyme derivatives were very active. However, most active and selective towards polyunsaturated fatty acids (PUFA) versus oleic plus palmitic acids (a fourfold factor) was CALB. On the other hand, the most selective derivatives towards EPA versus DHA (a 4.5-fold factor) were TLL and RML derivatives.  相似文献   

4.
The hydrolysis of palm oil, palm olein and palm stearin, soybean oil, corn oil and peanut oil by the commercial lipase fromCandida rugosa (formerly known asC. cylindracea) was studied. The optimal conditions for the hydrolysis of palm oil by the lipase were established. The lipase fromC. rugosa exhibits an optimal activity at 37 C and at pH 7.5. The optimal oil to hexane ratio is 1 g of oil to 0.5 ml hexane. The rate of hydrolysis of palm oil by the lipase is linear on a logarithmic scale. Under the same conditions, palm oil and palm olein were hydrolyzed at the same rate, whereas palm stearin was hydrolyzed much more slowly.  相似文献   

5.
Frost-damaged or prematurely harvested canola seed (rapeseed) may yield oil with a high chlorophyll content (50–60 μg/ml). Enzymatic hydrolysis of chlorophyll, added to buffer/surfactant, buffer/acetone or buffer/acetone/canola oil, to produce water-soluble chlorophyllide (green pigment) was studied using a crude chlorophyllase preparation (acetone-dried chloroplasts) from 15 to 20-day-old sugar beet seedlings. In buffer/surfactant, the optimum pH for enzyme activity was temperature dependent. At 30 C and 0.24% Triton X-100 (or 30% acetone), chlorophyllase showed maximum activity toward a crude chlorophyll preparation over the range of pH 8–10. At 60 C, the activity was more than twofold higher, with a sharp maximum at ∼pH 8. Mg2+ enhanced the activity with an optimal concentration of 50 mM. At pH 7.5, 50 C and in the presence of only 6% acetone, the enzyme showed high affinity for chlorophyll (Km=15μM or 13.5 μg/ml), suggesting that the natural chlorophyll concentrations found in green canola oils might facilitate high enzymatic efficiencies. The crude enzyme was stable in buffer/acetone at pH 7.5 and 50 C for at least two hr. With acetone concentrations as low as 6%, maximum enzyme activities in buffer and buffer/canola oil required intensive mixing (homogenization) of the various substrate, enzyme and liquid phases. In general, the rate and extent of chlorophyll hydrolysis were greater in buffer than in buffer/oil. In both reaction systems, chlorophyll hydrolysis slowed down with time due to accumulation of phytol, which proved to be a competitive inhibitor (Ki=11 μM or 3.3 μg/ml). The other hydrolysis product, chlorophyllide, did not affect enzymatic activity. Crude canola oil used in the reconstitution of green oil did not support enzymatic chlorophyll hydrolysis without prior degumming and desoaping. The optimum buffer/oil ratio of the reaction mixtures was above 2/1 (v/v).  相似文献   

6.
Synthesis of medium-chain glycerides by lipase in organic solvent   总被引:5,自引:0,他引:5  
Using commercial lipases from various microbial origins, medium-chain glycerides, such as mono-, di-, and tricaprin, were synthesized in isooctane from glycerol and capric acid. The enzyme reaction was performed with 0.35 M capric acid, 0.025 M glycerol, and 0.46 g silica gel to remove water in 5 mL of isooctane with 30 mg lyophilized lipase. Of the 21 kinds of lipases, 11 showed good synthetic activities. Lipases fromPseudomonas aeruginosa (Lipase PS),Rhizomucor miehei lipase andChromobacterium viscosum lipase (Lipase CV) showed high activities for the production of tricaprin, while lipase OF-360 (fromCandida rugosa) and lipase D (Rhizopus delemar) were good for dicaprin production. Lipases CC and MY fromC. rugosa (C. cylindracea) and lipase D (Rhizopus delemar) were good for dicaprin production. Lipases CC and MY fromC. rugosa (C. cylindracea) also showed high activities for dicaprin and tricaprin. Some lipases, especially lipase PS, had high thermal stability over 60°C. The optimal lyophilization pH to dehydrate the lipase coincides with the optimal buffer solution pH for hydrolysis.  相似文献   

7.
Lipase B (GCB) produced by the fungus Geotrichum candidum CMICC 335426 is known for its high specificity towards cis-Δ9 unsaturated fatty acids. The wild-type lipase (not genetically modified) as well as the lipase obtained by heterologous expression of the corresponding gene in Pichia pastoris (genetically modified) were studied in a process aiming to produce an oil containing very little saturated fatty acids (SAFA). The approach described in this paper is based on the selective hydrolysis of sunflower oil (12% SAFA) using the G. candidum type B (GCB) lipases. Depending on the lipase input, up to 60% w/w degree of hydrolysis was obtained within 6–8 h. Because of the high specificity of the GCB lipases (specificity factor ∼30), the level of unsaturates in the free fatty acid fraction was >99% w/w. In contrast with literature data, no loss of specificity was observed, even at the highest degree of hydrolysis obtained. Though both GCB lipases are stable at 30°C, the rate of hydrolysis decreased considerably during the process. Product inhibition as well as time-dependent deactivation (half-life ≈2 h) were shown to be involved. After separation of the oil phase, the unsaturated free fatty acids were recovered from the mixture by evaporation and reconverted to triglycerides by enzymatic esterification with glycerol. Because the GCB lipases have a very low efficiency for esterification, this reaction was carried out with immobilized Rhizomucor miehei lipase. Under continuous removal of the water generated during the process, >95% triglycerides were obtained in less than 24 h. Standard deodorization resulted in an odorless, colorless, and tasteless oil with less than 1% SAFA.  相似文献   

8.
Production of ω-3 fatty acid concentrates from seal blubber oil (SBO) and menhaden oil (MHO) upon enzymatic hydrolysis by Candida cylindracea lipase was optimized. In this process, the content of total ω-3 fatty acids, Y 1; eicosapentaenoic acid, Y 2; and docosahexaenoic acid, Y 3, in the final product was maximized. A three-factor central composite rotatable design was used to study the effect of enzyme concentration (X 1), reaction time (X 2), and reaction temperature (X 3). Second-order polynomial regression models for Y 1, Y 2, and Y 3 were employed to generate response surfaces. After hydrolysis, a maximum of 54.3% total ω-3 fatty acids was obtained from SBO at an enzyme concentration of 308 U/g oil, a reaction time of 40 h, and a reaction temperature of 37°C. Similarly, a maximum of 54.5% total ω-3 fatty acids was obtained from MHO at an enzyme concentration of 340 U/g oil, a reaction time of 45 h, and a reaction temperature of 38°C.  相似文献   

9.
The activity of Chromobacterium viscosum lipase (glycerol‐ester hydrolase, EC 3.1.1.3) entrapped in AOT/isooctane and AOT/Tween 85/isooctane reverse micelles was significantly increased by the addition of short chain methoxypolyethylene glycols (MPEGs), taking the hydrolysis of olive oil as a model reaction. The molecular weight of MPEG had a strong effect on the lipase activity, and MPEG of nominal molecular weight 550 was found to be the most effective. To optimize the factors affecting enzymatic hydrolysis of olive oil in reverse micellar systems containing MPEG 550, the effect of various parameters, such as Wo (molar ratio of water to surfactant), pH, ionic strength, surfactant concentration and temperature were investigated. A kinetic model considering the substrate adsorption equilibrium between the bulk phase of organic solvent and the micellar phase was also successfully used to understand the enzyme activity in the presence of MPEG 550. Both the Michaelis constant and the substrate adsorption equilibrium constant were obviously reduced as compared with those obtained in the simple AOT reverse micellar system. © 2001 Society of Chemical Industry  相似文献   

10.
Candida rugosa lipase was extracted from aqueous solutions into organic solvents by forming an ion‐paired complex with sodium bis(2‐ethylhexyl)sulfosuccinate (AOT). The optimal aqueous pH for lipase recovery was 4.5 and the optimal CaCl2 concentration was 10 mmol dm?3. The lipase recovery decreased with increasing aqueous enzyme concentration but increased with increasing AOT concentration in the organic phase. The presence of polar co‐solvents in the aqueous phase did not obviously improve the lipase recovery, which was also little influenced by the type of hydrophobic organic solvent used for solubilising AOT. Surprisingly, no detectable activity of the ion‐paired C. rugosa lipase was observed for both the esterification of lauric acid with 1‐propanol in isooctane and the hydrolysis of olive oil in isooctane containing an appropriate amount of water. The ion‐paired C. rugosa lipase mediated the enantioselective crystallisation of racemic ketoprofen in isooctane, indicating the feasibility of using it as a chiral mediator for the enantioseparation of hydrophobic racemic compounds in organic systems. Copyright © 2006 Society of Chemical Industry  相似文献   

11.
Hydrolysis of olive oil, soybean oil, mink fat, lard, palm oil, coconut oil, and a hydrogenated, hardened oil with lipase from anAspergillus sp. has been studied. The lipase had high specific activity (60,000 U/g) and did not show any positional specificity. The lipase proved to be a more effective catalyst than Lipolase fromA. oryzae, with an optimal activity at 37°C and pH 6.5–7.0. It was activated by Ca2+ but inactivated by organic solvents such as isopropanol and propanone. All substrates examined could be hydrolyzed to corresponding fatty acids with this enzyme at concentrations of 5–30 U/meq with yields of 90–99% in 2–24 h. The degree of hydrolysis was almost logarithmically linear with reaction time and occurred in two stages. The lipase was stable and could be repeatedly recycled for hydrolysis.  相似文献   

12.
A 46% γ-linolenic acid (GLA)-containing oil was produced by selective hydrolysis of borage oil (GLA content, 22%) at 35°C for 15 h in a mixture containing 50% water and 20 units (U)/g reaction mixture of Candida rugosa lipase. The GLA content was not raised over 46%, even though the hydrolysis extent was increased by extending the reaction time and by using a larger amount of the lipase. However, 49% GLA-containing oil was produced by hydrolysis in a reaction mixture with 90% water. This result suggested that free fatty acids (FFA) that accumulated in the mixture affected the apparent fatty acid specificity of the lipase in the selective hydrolysis and interfered with the increase of the GLA content. To investigate the kinetics of the selective hydrolysis in a mixture without FFA, glycerides containing 22, 35, and 46% GLA were hydrolyzed with Candida lipase. The result showed that the hydrolysis rate decreased with increasing GLA content of glycerides, but that the release rate of GLA did not change. Thus, it was found that the apparent fatty acid specificity of the lipase in the selective hydrolysis was also affected by glyceride structure. When 46% GLA-containing oil was hydrolyzed at 35°C for 15 h in a mixture containing 50% water and 20 U/g of the lipase, GLA content in glycerides was raised to 54% at 20% hydrolysis. Furthermore, GLA content in glycerides was raised to 59% when the hydrolysis extent reached 60% using 200 U/g of the lipase. These results showed that repeated hydrolysis was effective to produce the higher concentration of GLA oil. Because film distillation was found to be extremely effective for separating FFA and glycerides, large-scale hydrolysis of borage oil was attempted. As a result, 1.5 kg of 56% GLA-containing oil was obtained from 7 kg borage oil by repeated reaction.  相似文献   

13.
Structured lipids were synthesized by transesterification of peanut oil and caprylic acid in a stirred-batch reactor. Different substrate molar ratios (1:1 to 1:4, peanut oil/caprylic acid) were used. The reaction was performed for 72 h at 50°C catalyzed by IM60 lipase from Rhizomucor miehei (10 g, 2% w/w substrate) in the absence of organic solvent. The highest incorporation of caprylic acid was obtained with a 1:2 molar ratio (peanut oil/caprylic acid) after 72 h reaction. With a 1:2 molar ratio, the incorporation increased by 28% from 1:1. On the other hand, a 1:4 molar ratio gave the lowest incorporation during the reaction. The effect of different mixing speeds (200, 640, or 750 rpm) on reaction was studied with a 1:2 substrate molar ratio for 24 h. A high incorporation of caprylic acid (14.3 mol%) was obtained at 640 rpm, while 200 rpm gave the lowest incorporation (2.2 mol%), suggesting that good mixing is essential in a stirred-batch reactor. After 24 h of reaction at different rpm, IM60 lipase was recovered, washed with hexane, and reacted with substrates to study its stability after reaction at different mixing speeds. The results showed that caprylic acid incorporation was similar (24.9, 24.3, 24.2 mol%) at 200, 640, and 750 rpm, respectively. When 20 g of IM60 lipase (4% w/w substrate) instead of 10 g was used in a 1:1 substrate molar ratio reaction, the incorporation of caprylic acid increased by 26% after 72 h. To study enzyme reuse, 10 g of IM60 lipase was used in a 1:1 substrate molar ratio for 24 h at 640 rpm. The incorporation of caprylic acid gradually decreased with increased number of reuses. During five times of reuse, 15, 13.9, 9.6, 6.7, and 9.7 mol% of caprylic acid were incorporated into peanut oil, respectively.  相似文献   

14.
γ‐Decalactone is an industrially interesting peach‐like aroma compound that can be produced biotechnologically through the biotransformation of ricinoleic acid. Castor oil (CO) is the raw material most used as the ricinoleic acid source. The effect of different CO concentrations on the γ‐decalactone production by Yarrowia lipolytica was investigated in batch processing, and 30 g L?1 was found to be the optimal oil concentration. Under these conditions, cells were able to produce lipase but at low activity levels, which might limit ricinoleic acid release and consequently, the γ‐decalactone production rate. Thus, the enzymatic hydrolysis of CO by commercial lipases was studied under different operating conditions. Lipozyme TL IM was found to be the most efficient and the optimal hydrolysis conditions were pH 8 and 27 °C. The use of hydrolyzed CO in the aroma production allowed a decrease in the lag phase for γ‐decalactone secretion.  相似文献   

15.
Candida rugosa lipase was immobilized on poly(N‐methylolacrylamide) by physical adsorption. The biocatalyst performance (immobilized lipase) was evaluated in both aqueous (hydrolysis) and organic (butyl butyrate synthesis) media. In the first case, a comparative study between free and immobilized derivatives was provided in terms of pH, temperature and thermal stability following the olive oil hydrolysis, establishing new optimum values. In the second case, the influence of temperature, biocatalyst concentration and acid/alcohol molar ratio was simultaneously studied according to a 23 full experimental design. The highest molar conversion (96 %), volumetric productivity (1.73 g L–1 h–1) and specific esterification activity (1.00 μM mg–1 min–1) were obtained when working at the lowest level of temperature and butyric acid in excess. Under these conditions, repeated batch use of the immobilized enzyme was performed and half‐life time (t1/2) was found to be 145 h.  相似文献   

16.
Poor H2O2-resistance by enzymes is a key bottleneck in the epoxidation process of oil by enzymatic methods. In this study, the stability of three lipases, from Aspergillus oryzae lipase (AOL), Aspergillus fumigatus lipase B (AflB), and marine Janibacter (MAJ1), in the presence of H2O2 was evaluated in different types of natural deep eutectic solvents (NADES). This stability was strengthened significantly in the NADES compared to the buffer. Specifically, AOL retained 84.7% of its initial activity in the presence of choline chloride/sorbitol (1:1 M ratio) and 3 mol L−1 H2O2 after 24 h incubation at 40°C. In addition, the two-phase epoxidation process was optimized with AOL in ChCl/sorbitol to reach up to 96.8% conversion under the optimized conditions (molar ratio of octanoic acid/H2O2/C=C-bonds = 0.3:1.5:1, enzyme loading of 15 U g−1 of soybean oil, ChCl/sorbitol content of 70.0% of the weight of hydrophilic phase, and reaction temperature of 50°C). Moreover, the lipase dispersed in NADES retained approximately 66% of its initial activity after being used for seven batch cycles. Overall, NADES-based enzymatic epoxidation is a feasible and promising strategy for the synthesis of epoxidized oils.  相似文献   

17.
Two oils containing a large amount of 2-arachidonoyl-TAG were selected to produce structured TAG rich in 1,3-capryloyl-2-arachidonoyl glycerol (CAC). An oil (TGA58F oil) was prepared by fermentation of Mortierella alpina, in which the 2-arachidonyoyl-TAG content was 67 mol%. Another oil (TGA55E oil) was prepared by selective hydrolysis of a commercially available oil (TGA40 oil) with Candida rugosa lipase. The 2-arachidonoyl-TAG content in the latter was 68 mol%. Acidolysis of the two oils with caprylic acid (CA) using immobilized Rhizopus oryzae lipase showed that TGA55E oil was more suitable than TGA58F oil for the production of structured TAG containing a higher concentration of CAC. Hence, a continuous-flow acidolysis of TGA55E oil was performed using a column (18×125 mm) packed with 10 g immobilized R. oryzae lipase. When a mixture of TGA55E oil/CA (1∶2, w/w) was fed at 35°C into the fixed-bed reactor at a flow rate of 4.0 mL (3.6 g)/h, the degree of acidolysis initially reached 53%, and still achieved 48% even after continuous operation for 90 d. The reaction mixture that flowed from the reactor contained small amounts of partial acylglycerols and tricaprylin in addition to FFA. Molecular distillation was used for purification of the structured TAG, and removed not only FFA but also part of the partial acylglycerols and tricaprylin, resulting in an increase in the CAC content in acylglycerols from 44.0 to 45.8 mol%. These results showed that a process composed of selective hydrolysis, acidolysis, and molecular distillation is effective for the production of CAC-rich structured TAG.  相似文献   

18.
To enhance the Chromobacterium viscosum lipase (glycerol‐ester hydrolase; EC 3.1.1.3) activity for the reaction of water‐insoluble substrates, the AOT/isooctane reverse micellar interface was modified by co‐adsorption of a non‐ionic surfactant. Polyoxyethylene sorbitan trioleate (Tween 85) was used as the non‐ionic surfactant and olive oil as a water‐insoluble substrate. An appreciable increase of lipase activity was observed and at higher Wo values (where Wo = molar ratio of water to total surfactants of the micellar system) there was no sharp fall of the enzyme activity such as a typical bell‐shaped profile. The kinetic model for the lipase‐catalysed hydrolysis of olive oil in AOT/isooctane reverse micellar system was applied to the enzymatic reaction in this mixed reverse micellar system. It was found that the predictions of the model agree well with the experimental kinetic results and that the adsorption equilibrium constant of olive oil molecules between the micellar phase and the bulk phase of the organic solvent is smaller in AOT/Tween 85 mixed reverse micellar systems than in simple AOT reverse micellar systems. © 1999 Society of Chemical Industry  相似文献   

19.
Lipase activity from castor bean seed powders was evaluated in hydrolysis reactions at 37 °C. The effects of different concentrations of lipase powder (LP), substrate (high oleic sunflower oil, O) and surfactant (gum arabic, A) on lipase activity (R) were assessed using experimental designs. Considered variable bounds were: 0.05–0.15 gLP, 0.07–0.20 oil:aqueous phase (w/w) and 0–0.025 g gum arabic/mL. All variables had significant effects on the transformed response, R 1/2. The most important result was the negative effect of gum arabic in lipase activity, even when high oil concentrations were used. Experimental lipase activities involved in this work were within 0.32–16.90 mmolFFA/goil·gLP·h. Using 0.05 gLP and 0.20 oil:aqueous phase (w/w) without gum arabic, the activity of 20.47 ± 7.19 mmolFFA/goil·gLP·h was reached.  相似文献   

20.
Lipases from Geotrichum candidum were produced in two different medium: A = 12 % (w/v) clarified corn steep liquor (CCSL) + 0.6 % (w/v) soybean oil (SO) and B = 3.5 % (w/v) yeast hydrolysate (YH) + 0.7 % (w/v) SO. Lipases were partially purified from both media by hydrophobic interaction chromatography using 3.0 mol L?1 of NaCl as mobile phase, and they were characterized in the crude and partially purified forms. The recovery of lipase activity from CCSL and YH via HIC were 96 and 94.3 %, and the purification factors were 44.3 and 86.7‐fold, respectively. All evaluated lipases had similar optimum pH (7.0–7.7), but, for the CCSL crude lipase, optimum temperature (47 °C) was 10 °C higher than others lipases evaluated. CCSL crude lipase possessed a higher thermo stability than YH crude lipase, e.g., at 37 °C (pH 7.0) the half‐life of CCSL crude lipase was 19.25 h and at pH 8.0 (30 °C) the half‐life was 48 h, which are five and ten times higher than with YH crude lipase, respectively. On the other hand, the YH crude lipase possessed a higher catalytic constant (kcat = 2.3 min?1) but with almost the same catalytic efficiency (Km/kcat = 32.12 mg mL min?1) in relation to CCSL crude lipase. The lipases differ in biocatalytic properties between substrates, suggesting that the two lipases can be employed for different applications.  相似文献   

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