Molar Ratio Of Free Fatty Acid Research Articles

Chicken tallow, a low-cost feedstock for the two-step lipase-catalysed synthesis of biolubricant

Biolubricants are oleochemical esters that are non-toxic to the environment, and they are preferred because of their high-performance activities in various automobile and industrial fields. In this study, chicken tallow has been explored as an alternative to a non-renewable source, which acts as a low-cost feedstock for synthesizing biolubricants in a two-step hydro esterification process catalysed by Candida rugosa lipase (CRL). The enzymatic hydrolysis of chicken tallow is optimized at different time intervals at 40 °C, and the maximum release of 160.2 µmol min−1 free fatty acids (FFAs) is observed at 100 min. The hydrolysed FFAs are characterized by the gas chromatography-mass spectrometry (GC-MS) analysis that has depicted the fatty acid methyl esters (FAMEs) composition of the tallow oil. The recovered FFA is then enzymatically esterified with trimethylolpropane (TMP) to produce TMP esters. Optimization studies are performed to explore the effect of factors such as time, temperature, amount of the enzyme, and TMP: FFA molar ratio for the esterification process. Thus, the optimal conditions for achieving a maximal hydroxyl group conversion of 60% during TMP ester production include incubation time (120 min), temperature (35 °C), lipase concentration (3% w/w), and TMP: FFA molar ratio (1:4). Fourier transform infrared spectroscopy (FT-IR), and nuclear magnetic resonance (NMR) studies confirm the synthesized TMP esters. Moreover, physicochemical properties such as viscosity, cloud point (CP), and calorific value (CV) are found to be 36 mm2/s, 7159.14 cal/g, and 20 °C, respectively.

Lipase-catalyzed synthesis of 1,3-diacylglycerols containing stearidonic, γ-linolenic and α-linolenic acids in a solvent-free system

1,3-Diacylglycerols (1,3-DAG) are minor components in edible oils with potential for the management of overweight and obesity. In this work, 1,3-DAG containing stearidonic acid (SDA), γ-linolenic acid (GLA), and α-linolenic acid (ALA), were synthesized by lipase-mediated catalysis following a Taguchi experimental design. SDA, GLA, and ALA are polyunsaturated fatty acids (PUFA) able to act as precursors of anti-inflammatory lipid mediators in the human body and may help with prevention or relief of inflammatory diseases. Solvent-free synthesis of 1,3-DAG was successfully performed by esterifying glycerol with free fatty acids (FFA) obtained from Echium plantagineum seed oil. Crude reaction products were further purified by saponification. Two lipases (Lipozyme® RM-IM and Lipozyme® 435) and three variables (substrate molar ratio, lipase load and reaction time) were used to optimize the reaction conditions. At the optimal conditions, 88.7 mol% of DAG was produced (68.0 mol% 1,3-DAG and 20.7 mol% 1,2-DAG) using Lipozyme® 435 at 60 °C, a glycerol:FFA molar ratio of 1:3, a lipase load of 2.0 wt%, and 4 h reaction time. Proportions of SDA, GLA and ALA in the 1,3-DAG were 32.7, 32.3 and 22.0% respectively. The synthesized 1,3-DAG have potential as functional ingredients in foods for weight and obesity management.

Characterizing Reaction Space in the Continuous‐Flow Esterification of Oleic Acid Using a Sulfonated Hydrothermal Carbon Catalyst

AbstractContinuous‐flow catalytic esterification of free fatty acids (FFA) with methanol in the presence of sulfonated hydrothermal carbon (SHTC) as catalyst was studied. Using a Box‐Behnken experimental design protocol, the effects of residence time, methanol:acid molar ratio, and water concentration on the conversion of oleic acid into methyl oleate were investigated. The optimum conditions for achieving esterification greater than 90 % at 100 °C were determined to be 11‐minute residence time, a MeOH:FFA molar ratio >14.6 and up to 14.9 % water. The SHTC was used continuously for 4.5 days without a significant decrease in catalytic performance. The results confirmed that SHTC is an effective solid acid catalyst in a continuous flow system for the esterification of FFA.

Design of a sustainable process for enzymatic production of ethylene glycol diesters via hydroesterification of used soybean cooking oil

The aim of this study was to produce diol diesters, an important class of synthetic esters with lubricant properties, via enzymatic hydroesterification of used soybean cooking oil (USCO). Initially, free fatty acids (FFAs) were produced through hydrolysis of USCO catalyzed using powder lipase extract from Candida rugosa. Afterwards, different diols and FFAs were esterified using Eversa® Transform 2.0, a low-cost liquid lipase derived from Thermomyces lanuginosus, immobilized via interfacial activation on polystyrene-divinylbenzene (PSty-DVB) beads as biocatalyst. The immobilization improved its catalytic activity and the best performance was observed using ethylene glycol (EG). Thus, it was selected for further ester production optimization. The effect of relevant factors on EG diesters production was assessed through a central composite rotatable design (CCRD). As a result, full OH conversion was achieved at 65 °C using EG:FFA molar ratio of 1:3% and 18% of mass of heterogeneous biocatalyst per mass of starting materials after 40 min of reaction. Maximum OH conversion was only 32.5% using soluble lipase under such conditions. The prepared biocatalyst retained ≈ 37% of its original activity after seven successive esterification batches. Viscosity index (166.2 ± 18.2), pour point (–9 ± 2 °C) and density at 20 °C (0.8794) values of the produced EG diesters were similar to other EG esters produced from soybean oil in literature and commercial synthetic neopolyol esters.

Valorization of palm oil soap stock waste toward for biodiesel production: Process optimization under zero waste concept

Palm oil soap stock (POSS) was recycled from bio-waste to bio-fuel. Firstly, POSS was converted through acidification to be acidified POSS (APOSS) coupled with solvent extraction. APOSS with a high content of free fatty acids (FFAs) (90.94%) was obtained. Subsequently, the FFAs in APOSS were converted to biodiesel via esterification, catalyzed by immobilized alginate-polyvinyl alcohol (ALG-PVA) lipase. The key factors affecting the reaction, such as the temperature (30–50 °C), methanol to FFA molar ratio (2:1 to 4:1), and agitation rate (150–250 rpm) were optimized by statistical response surface methodology (RSM). The highest biodiesel yield was achieved with a reaction temperature of 40 °C, methanol/FFA molar ratio of 3:1, and 200 rpm agitation rate, as the optimal conditions. Furthermore, the biocatalyst can be reused up to 16 cycles. Interestingly, the alternative biodiesel production process reported herein promotes zero waste from the palm oil refinery process.

Combination of fatty acids extraction and enzymatic esterification for biodiesel production using sludge palm oil as a low-cost substrate

The alternative approach to the production of biodiesel from sludge palm oil (SPO) via two steps of extraction and enzymatic esterification was performed. Free fatty acids (FFAs) from SPO were obtained through saponification reaction and subsequent extraction. The FFAs were further converted to biodiesel (fatty acids methyl esters) via esterification reaction catalysed by immobilised Rhizopus oryzae lipase on alginate-polyvinyl alcohol (PVA) beads. The esterification reaction was investigated by variations of temperature (30–50 °C), molar ratio of methanol to FFAs (1:1 to 5:1), agitation rate (100–300 rpm) and for 4 h. The results were revealed that optimal condition for biodiesel production reached at reaction temperature of 40 °C, methanol to FFAs molar ratio of 3:1 and agitation rate of 200 rpm. Under the optimum condition, the highest biodiesel yield of 91.30% was achieved. Successfully, biodiesel production from SPO gave high conversion rate. In addition, the biocatalyst also showed in high catalytic efficiency and stability up to 15 cycles. The process cost could be reduced cost effectively for biodiesel production when a low cost substrate of SPO as well as the capable biocatalyst were used.

Study of a reactor model for enzymatic reactions in continuous mode coupled to an ultrasound bath for esters production.

The main objective of this work was to investigate the enzymatic production of ethyl esters in continuous mode coupled to an ultrasound bath. For esterification reactions soybean free fatty acids (FFA) and ethanol were used as substrates, and Novozym 435 and Lipozyme TL IM, as catalysts. The experimental system consisted of a packed bed glass reactor immersed in an ultrasound bath and the following variables were studied: ethanol to FFA molar ratio of 1:1, 1:3 and 1:6, substrates flow rate of 2.5 and 5mL/min, at 65°C and 132W ultrasound power output. It was noticed that the excess alcohol favored the esterification reaction with the best conversions observed, 95%, at 6min reaction for 1:6 FFA to ethanol molar ratio, 2.5mL/min feeding flow rate. Increasing the substrates feeding flow rate decreased the conversion down to 87% and replacing the Novozym 435 by Lipozyme TL IM no satisfactory conversions were achieved. This type of reactor demonstrated good performance for ethyl esters production, opening promising perspectives for use in the production of other types of esters such as those aromatic and others with high value.

Production of esters from soybean oil deodorizer distillate in pressurized ethanol

The aim of this study was to obtain esters from soybean oil deodorizer distillate (SODD) in pressurized ethanol without the use of a catalyst. Experiments were carried out to evaluate the effects of the operating variables (pressure, temperature, residence time and ethanol to free fatty acids molar ratio) using a minimum factorial experimental design. The results indicate that increasing the temperature, pressure and residence time in the reactor enhanced the conversion of free fatty acids (FFA) while increasing the ethanol to FFA molar ratio decreased the conversion. The experiment carried out under optimum conditions (20MPa, 275°C, 20min and ethanol to FFA molar ratio of 7:1) reached ~87% of FFA conversion. The reaction kinetics was investigated at different temperatures and the results obtained reveal that a high rate of FFA consumption and conversions close to the thermodynamic equilibrium were quickly reached. At high temperatures (325 and 350°C) the conversion decreased with increasing residence time, indicating that the reverse reaction occurred. The reaction in two steps increased the FFA conversion, indicating that the conversions obtained were close to the thermodynamic equilibrium and the removal of water between the steps shifted the equilibrium, making it possible to achieve higher FFA conversion and ester yields.

English

Performance of chemical deacidification of crude palm oil (CPO) using aqueous NaOH solution in a polysulfone hollow fiber ultrafiltration membrane was investigated. The effects of operating temperature, NaOH concentration and flow rates on percentage of free fatty acids (FFA) removal, oil loss, soap entrainment and overall mass transfer coefficient were evaluated. Overall mass transfer coefficients, soap content in oil and neutral oil loss all increased when the temperature was increased from 60 to 70°C due to an increase of the FFA distribution value. A minimum 0.25 N of NaOH or a NaOH to FFA molar ratio of about 7.62 was required to facilitate the expected extraction efficiency. The increased oil flowrate slightly enhanced the solute transport kinetics, while the aqueous phase flowrate did not significantly influence deacidification efficiency or mass transfer coefficient. About 97% of FFA removal was achieved within 4 hours. The maximum oil loss observed was 11% and the highest soap content in the oil without separation step was 3150 ppm. The values of the overall mass transfer coefficient varied from 2.97×10 -7 to 7.71×10 -7 m/s. These results show the potential of using the non dispersive membrane contacting process for chemical deacidification of CPO as well as other vegetable oils.

Esterification of free fatty acids (FFA) of Green Seed Canola (GSC) oil using H-Y zeolite supported 12-Tungstophosphoric acid (TPA)

H-Y is one of the most typical and commercially available zeolites. In this research work, the effect of TPA impregnation in H-Y zeolite has been analyzed. The impregnated catalysts have been characterized in details using TGA, BET, ICP-MS, FTIR, XRD, XPS, NH3-TPD and EXAFS. The change in catalyst structural properties and catalytic activity with the TPA impregnation have been correlated with the help of artificial neural network (ANN). The catalytic activity of the prepared catalysts has been tested in esterification of pure oleic acids and free fatty acids (FFA) present in the green seed canola (GSC) oil. A 10.2% actual TPA loading in H-Y zeolite showed optimum catalytic activity in esterification of oleic acid. The reaction conversion of 99.3% (for oleic acid) and 97.2% (for FFA) were achieved, when 13.3wt% catalyst containing 10.2% TPA and 20:1 methanol to FFA molar ratio were used at 120°C and reaction time of 7.5h. The catalyst is proved to be reusable. Kinetics study shows that the activation energy of the esterification reaction is 66.3kJ/mol.

Biodiesel production from Acrocomia aculeata acid oil by (enzyme/enzyme) hydroesterification process: Use of vegetable lipase and fermented solid as low-cost biocatalysts

The aim of this study was to investigate a new process of enzyme/enzyme hydroesterification for biodiesel production using a low-cost acid oil (10.5wt.% acidity) from macauba (Acrocomia aculeata) pulp as raw material. The ethyl esters were produced by the hydrolysis of the macauba oil using vegetable enzyme (VE) obtained from dormant castor seeds followed by esterification of the released free fatty acids (FFAs) with ethanol catalyzed by fermented and dry babassu cake with lipase activity from Rhizomucor miehei. The vegetable enzyme-catalyzed hydrolysis produced 99.6% of FFAs after 6h in a medium with high oil concentration (50% v/v) and without organic solvent and emulsifier. For the esterification reaction, the best result was attained with an ethanol:FFA molar ratio of 2:1 and 15.1 U of dry fermented solid per g of FFAs at 40°C, which yielded 91% of conversion after 8h in a solvent-free system. In order to confirm the potential of the fermented solid as biocatalyst, it was confronted with the best commercial lipases and was also evaluated for its reuse. Similar conversions were obtained with the commercial lipases Novozym 435 and Lipozyme RM IM and the fermented solid. The fermented solid was reused in successive 6-h batches for esterification reactions and conversions of over 60% were maintained for eight cycles. After two consecutive esterification reactions the resulting biodiesel met important Brazilian standards such as: density (ASTM D4052), viscosity kinematic (ASTM D445), flash point (ASTM D93), carbon residue (ASTM D4530), free glycerol and total glycerol, monoglycerides and triglycerides (ASTM D6584). The ester content was of 96.7% (esters of fatty acids of 8–18 carbons). To the best of our knowledge, this is the first time that an enzyme/enzyme hydroesterification process using low cost biocatalysts obtained from vegetable and microorganism using solvent-free media in both reactions is described for the conversion of an acid and low value oil into biodiesel.

Synthesis of biolubricant components from waste cooking oil using a biocatalytic route

The call for “sustainable development” has laid special emphasis on the “go green” concept and thus countries worldwide are taking initiatives to procure successful “clean and green technologies”. In this milieu the uncongenial conventional mineral‐oil based lubricants, causing adverse environmental impacts, can efficaciously be replaced by biodegradable vegetable oil based biolubricants. This article presents successful utilization of waste cooking oil (WCO) to synthesize biolubricant using a biocatalytic route. The developed methodology includes a two‐step process of enzymatic (Candida rugosa) hydrolysis of WCO to free fatty acids (FFA), followed by biocatalytic (Novozyme 435) esterification of FFA with octanol in a solvent‐free system to produce the octyl esters (desired biolubricant components). A classical method of parametric study was employed to explore the effect of different physico‐chemical parameters on the esterification reaction. The reaction conditions to achieve maximum conversion (95%) in minimum time were, initial water content = 0.5 wt % of FFA, octanol: FFA molar ratio = 3:1, catalyst = 5 wt % of FFA and temperature = 60°C. Fourier Transform Infrared Spectroscopy confirmed that the product formed was ester. WCO thus serves as an alternative feedstock for biolubricant synthesis and additionally aids up in skillful waste minimization and reuse. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 933–940, 2014

Biolubricant synthesis from waste cooking oil via enzymatic hydrolysis followed by chemical esterification

AbstractBACKGROUNDLubricants manufactured conventionally from non‐renewable mineral oil resources are not biodegradable and are liable to cause adverse environmental impacts. Biodegradable vegetable oils present a promising lubricant feedstock alternative. Waste cooking oil (WCO), which otherwise finds no immediate potential utilization can be successfully used to synthesize bio‐lubricant. A novel synthetic method was developed by using the two‐step process of C. rugosa lipase‐mediated hydrolysis of WCO to free fatty acids (FFA) followed by Amberlyst 15H esterification of FFA with octanol. The octyl esters produced was the desired biolubricant.RESULTSThe effect of different physico‐chemical parameters like temperature, catalyst loading, agitation speed, molar ratio of octanol:FFA and the presence of different desiccants on the esterification reaction was examined. The optimum conditions to get maximum yield of biolubricant in minimum time were, octanol:FFA molar ratio = 3:1, temperature = 80 °C, catalyst = 2 g and desiccant (preferably silica gel powder) = 50% weight of FFA. Fourier transform infrared spectroscopy confirmed that the product formed was ester.CONCLUSIONBiolubricant (octyl esters) was prepared efficiently from WCO by the two‐step process developed. This novel approach represents a viable means of producing lubricants from wastes which are renewable in nature and can be an alternative to non‐renewable mineral oil feedstocks. Copyright © 2012 Society of Chemical Industry

Change in glyceride composition of olive pomace oil during enzymatic esterification.

Enzymatic esterification of free fatty acids of olive pomace oil with glycerol was investigated. The esterification reaction was carried out in the absence and presence of glycerol (glycerol to free fatty acids (FFA) molar ratio of 1/3 and 1/6). In the absence of glycerol, the FFA concentration decreased from 32 to 21% while the triglyceride concentration increased from 33 to 40% after of 8 h of reaction time. The most significant decrease in FFAs and increase in triglycerides was observed at the limiting concentration of glycerol (glycerol to FFA molar ratio of 1/3). The FFA concentration decreased to 2.5% and the triglyceride concentration increased up to 78%. The change in both FFA and triglyceride concentrations was found to be statistically significant (P < 0.05).

Serum fatty acid/albumin molar ratio and the risk of diseases

Free fatty acids (FFA) in blood are carried by serum albumin. A hypothesis is offered that conditions giving a high molar ratio of FFA to albumin may lead to dysfunction of the cells which are directly exposed to the high FFA/albumin ratio, i.e. the red and white blood cells, and endothelial cells. The hypothesis is supported by observations of (1) hemolytic effect of FFA, and protection by albumin in vitro, (2) inhibition of white blood cells by FFA, (3) increased FFA/albumin ratio and erythrocyte susceptibility to hemolysis in pre-eclampsia, (4) increased incidence of eclampsia in undernutrition, (5) the paradox that famine suppresses and refeeding activates malaria, and (6) an inverse relationship between serum albumin level and mortality.

Polyunsaturated fatty acids decrease the apparent affinity of vitamin D metabolites for human vitamin D-binding protein

The affinity of purified human vitamin D-binding protein from serum (DBP) for 25-hydroxyvitamin D 3 (25-OHD 3) and 1α,25-dihydroxyvitamin D 3 [1,25-(OH) 2D 3] was measured in the presence of free fatty acids (FFA), cholesterol, prostaglandins and several drugs. Mono- and polyunsaturated fatty acids markedly decreased the affinity of both 25-OHD 3 and 1,25-(OH) 2D 3 for DBP, whereas saturated fatty acids (stearic and arachidic acid), cholesterol, cholesterol esters, retinol, retinoic acid and prostaglandins (A 1 and E 1) did not affect the apparent affinity. Several chemicals known to decrease the binding of thyroxine to its plasma-binding protein did not affect the affinity of DBP. The apparent affinity of DBP for both 25-OHD 3 and 1,25-(OH) 2D 3 decreased 2.4- to 4.6-fold in the presence of 36 μM of linoleic or arachidonic acid, respectively. Only a molar ratio of FFA:DBP higher than 10,000 was able to decrease the binding of 25-OHD 3 to DBP by 20%. Much smaller ratio's of FFA:DBP (25 for arachidonic and 45 for oleic acid), however, decreased the binding of 1,25-(OH) 2D 3 to DBP. These latter ratio's are well within the physiological range. The addition of human albumin in a physiological albumin:DBP molar ratio did not impair the inhibitory effect of linoleic acid on the binding of [ 3H]25-OHD 3 to DBP. The binding and bioavailability of vitamin D metabolites thus might be altered by mono- and polyunsaturated but not by saturated fatty acids.

Effect of in vivo increase of free fatty acids on human plasma protein binding of furosemide.

The in vivo effects of increased free fatty acid (FFA) plasma levels on the protein binding of furosemide were investigated in 30 adult-onset diabetics and 22 patients suffering from bacterial infections (gram- negative bacilli and gram-positive cocci). In diabetics, FFA were 2.43 +/- 1.63 mEq/l, and in subjects with bacterial infections 1.82 +/- 0.92 mEq/l. Furthermore, the percent of oleic acid and, to a very lesser extent, palmitoleic acid increased linearly with the increase of the FFA plasma level. The free furosemide fraction was about 1% or less in subjects with a molar ratio of FFA to albumin below 4, but a displacement of the drug from the plasma proteins occurred consistently when this ratio was above 4. At a molar ratio of FFA to albumin as high as 9.34, the free furosemide was 6.7% of the total concentration (8.9 microgram/ml). These results do not quantitatively agree with previous in vitro studies employing single fatty acids and human serum albumin, suggesting that in vivo plasma composition is not adequately reproduced during in vitro experiments on protein-binding displacement of drugs by FFA.

The effect of disease states on serum protein binding of antimicrobials

Serum protein binding of antimicrobials is altered in various disease states. In uremia, the binding of many organic acids to serum proteins is reduced. The defect in binding is 1. greater than can be accounted for by hypoalbuminemia alone, 2. unchanged by dialysis, 3. transferred in the protein but not the ultrafiltrate fraction, 4. corrected by a successful kidney transplant, and 5. corrected by treatment with activated charcoal at low pH. These data suggest that the binding defect is due to the accumulation of an inhibitor. The nature of the inhibitor is currently unknown. The accumulation of certain endogenous compounds such as bilirubin and free fatty acids (FFA) can also affect protein binding of antimicrobials. Elevation of the molar ratio of FFA to albumin during pump perfusion in patients undergoing cardiac bypass produces a binding defect. Various disease states probably behave similarly.

Effect of ACTH on lipolysis in adipose tissue of normal and adrenalectomized rats in vivo

Parametrial fat-pads of fed rats were perfused in vivo. Rates of release of glycerol and free fatty acids (FFA) were determined from venous-arterial difference and plasma flow. Adrenalectomy lowered basal release of FFA and glycerol, but not reesterification of FFA within the fat-pad. ACTH (5 mug iv) in normal rats increased release of FFA and glycerol (mumol-g-1-h-1) from basal values of 0.90 and 0.48 to 3.2 and 1.3, respectively, and in adrenalectomized rats from 0.41 and 0.33 to 1.5 and 3.1, respectively. Thus in normal rats ACTH increased the molar ratio of FFA to glycerol released from 1.9 to 2.5, whereas in adrenalectomized rats the ratio fell from 1.3 to 0.5. After stimulation of lipolysis in normal rats 85% of the FFA formed were released but only 20% in adrenalectomized rats; the remainder was reesterified to triglyceride. It is concluded that adipose tissue of adrenalectomized rats is sensitive to the lipolytic activity of ACTH, but increased glucose utilization by adipocytes in the absence of glucocorticoid enhances reesterification and reduces release of FFA by the tissue.