Transesterification Of Olive Oil Research Articles

Amine and aldehyde functionalized mesoporous silica on magnetic nanoparticles for enhanced lipase immobilization, biodiesel production, and facile separation

In this research, synthesis of fatty acid methyl ester (FAME) from olive oil as model feedstock was carried out in the presence of Rhizopus oryzae lipase (ROL) that was immobilized on the mesoporous silica magnetic nanoparticles (MNPs). MNPs were coated with mesoporous silica (MS) functionalized by amine and aldehyde groups used for immobilization of a lipase, used for biodiesel production, and easy magnetic separation of the immobilized lipase from the biodiesel product. MNPs were synthesized by using the co-precipitation method and coated with MS by sol-gel synthesis using cetyltrimethylammonium bromide (CTAB) as a template for mesoporous formation. ROL was immobilized on these supports via physical adsorption and covalent attachment. Enzyme loading efficiency on mesoporous was doubled compared to that on bare MNPs. Also, the covalent bonding led to an increase in enzyme loading from 67.8 to 82.4%. The physico-chemical properties of MNPs were determined by XRD, EDX, VSM, FESEM, BET, and FTIR and were correlated with their activities for biodiesel synthesis. The evaluations of hydrolytic activity and kinetic parameters revealed that MNPs@MS-AP-GA is a suitable nanomaterial for ROL immobilization. Transesterification of olive oil using ROL-MNPs@MS-AP-GA showed the highest biodiesel production of 84.6% among other nanobiocatalysts.

Lipase from Rhizopus oryzae R1: in-depth characterization, immobilization, and evaluation in biodiesel production

BackgroundRhizopus species is among the most well-known lipase producers, and its enzyme is suitable for use in many industrial applications. Our research focuses on the production of lipase utilizing waste besides evaluating its applications. ResultsAn extracellular lipase was partially purified from the culture broth of Rhizopus oryzae R1 isolate to apparent homogeneity using ammonium sulfate precipitation followed by desalting via dialysis. The partially purified enzyme was non-specific lipase and the utmost activity was recorded at pH 6, 40 °C with high stability for 30 min. The constants Km and Vmax, calculated from the Lineweaver-Burk plot, are 0.3 mg/mL and 208.3 U/mL, respectively. Monovalent metal ions such as Na+ (1 and 5 mM) and K+ (5 mM) were promoters of the lipase to enhance its activity with 110, 105.5, and 106.5%, respectively. Chitosan was used as a perfect support for immobilization via both adsorption and cross-linking in which the latter method attained immobilization efficiency of 99.1% and reusability of 12 cycles. The partially purified enzyme proved its ability in forming methyl oleate (biodiesel) through the esterification of oleic acid and transesterification of olive oil. ConclusionThe partially purified and immobilized lipase from Rhizopus oryzae R1 approved excellent efficiency, reusability, and a remarkable role in detergents and biodiesel production.

Comparison of breakdown voltage of vegetable olive with mineral oil, natural and synthetic ester liquids under DC voltage

This paper deals with a comparative study of the negative and positive DC breakdown voltages of different insulating liquids namely two natural esters (an extra virgin olive oil (OO) without additive and rapeseed oil), two synthetic ester fluids (a methyleolate obtained by transesterification of olive oil and tetraester), and a naphthenic mineral oil (MO); an oils mixture namely 80% OO + 20% MO is also investigated. Statistical analysis of the experimental data is also performed. The obtained results are also compared with those obtained in our previous work under AC and lightning impulse voltages. It is observed that the negative and positive DC breakdown voltages of natural esters are higher than those of mineral oil. On the other hand, the DC breakdown voltage of (80% OO + 20 % MO) mixture shows comparable behavior to that of mineral oil. The DC negative breakdown voltages are higher than the positive ones in the tested liquids. It is also shown that the DC breakdown voltage values of the investigated liquids generally obey the normal distribution.

Establishing a green platform for biodiesel synthesis via strategic utilization of biochar and dimethyl carbonate

To establish a green platform for biodiesel production, this study mainly investigates pseudo-catalytic (non-catalytic) transesterification of olive oil. To this end, biochar from agricultural waste (maize residue) and dimethyl carbonate (DMC) as an acyl acceptor were used for pseudo-catalytic transesterification reaction. Reaction parameters (temperature and molar ratio of DMC to olive oil) were also optimized. The biodiesel yield reached up to 95.4% under the optimal operational conditions (380°C and molar ratio of DMC to olive oil (36:1)). The new sustainable environmentally benign biodiesel production introduced in this study is greener and faster than conventional transesterification reactions.

Synthesis of ascorbyl oleate by transesterification of olive oil with ascorbic acid in polar organic media catalyzed by immobilized lipases

The reaction of transesterification between oils (e.g., olive oil) and ascorbic acid in polar anhydrous media (e.g., tert-amyl alcohol) catalyzed by immobilized lipases for the preparation of natural liposoluble antioxidants (e.g., ascorbyl oleate) was studied. Three commercial lipases were tested: Candida antarctica B lipase (CALB), Thermomyces lanuginosus lipase (TLL) and Rhizomucor miehei lipase (RML). Each lipase was immobilized by three different protocols: hydrophobic adsorption, anionic exchange and multipoint covalent attachment. The highest synthetic yields were obtained with CALB adsorbed on hydrophobic supports (e.g., the commercial derivative Novozym 435). The rates and yields of the synthesis of ascorbyl oleate were higher when using the solvent dried with molecular sieves, at high temperatures (e.g. 45°C) and with a small excess of oil (2mol of oil per mol of ascorbic acid). The coating of CALB derivatives with polyethyleneimine (PEI) improved its catalytic behavior and allowed the achievement of yields of up to 80% of ascorbyl oleate in less than 24h. CALB adsorbed on a hydrophobic support and coated with PEI was 2-fold more stable than a non-coated derivative and one hundred-fold more stable than the best TLL derivative. The best CALB derivative exhibited a half-life of 3 days at 75°C in fully anhydrous media, and this derivative maintained full activity after 28 days at 45°C in dried tert-amyl alcohol.

Biodiesel production using cross-linked Staphylococcus haemolyticus lipase immobilized on solid polymeric carriers

Abstract Various plant oils and animal fats can be used for the production of biodiesel, a renewable and eco-friendly alternative fuel. In this research, transesterification of olive oil and methanol was performed using Staphylococcus haemolyticus L62 lipase expressed in Escherichia coli cells. L62 lipase was relatively methanol-stable and could produce biodiesel by a one-step methanol-feeding process. This enzyme was immobilized on a poly (methacrylate-co-divinyl benzene) resin by two different methods: hydrophobic adsorption/entrapment (H-L62) and hydrophobic adsorption/entrapment plus covalent cross-linking (HC-L62). Both immobilized enzymes showed quite increased temperature and pH stabilities, whereas they had very similar optimal temperature and pH in comparison with the soluble free enzyme. Soluble L62, H-L62 and HC-L62 lipases could produce biodiesel efficiently from olive oil. Among them, HC-L62 lipase was the most robust enzyme on the basis of multiple reusability. HC-L62 produced biodiesel with various plant oils including palm, olive fomase oils as well as waste cooking oil, suggesting that it can be utilized as a biocatalyst in the biodiesel industry.

Enzymatic transesterification of olive oil and its precursors

The effect of different solvents and three different acyl acceptors on the transesterification of triolein (as a model compound) was investigated. The yield of biodiesel (methyl or ethyl ester) was monitored as a function of time. The yield of the product was also determined in a solvent-free system for two different modes of stirring. The results indicate that the highest yield is obtained in a solvent-free system with mechanical stirring. Methyl acetate is also effective as a solvent and acyl acceptor. Biodiesel was also produced by transesterification of triglycerides (triolein) present in olive oil with methanol and Novozym® 435. The effect of the molar ratio of methanol to triolein, mode of methanol addition, enzyme activity and reaction temperature on overall conversion and yield was determined. The final conversion and yield of biodiesel after a reaction time of 24 h were unaffected by changes in these parameters over the range studied. Preliminary findings indicate that the results obtained from small scale reactors and fresh oil can be extended to larger reactors and used oil.

Solid-phase microextraction and on-line methylation gas chromatography for aliphatic carboxylic acids.

Methylation of carboxylic acids upon syringe injection of a mixture of the acid sample and phenyltrimethylammonium hydroxide (PTMAH) into the GC injection port is a convenient but under-utilized derivatization procedure. To minimize potential instrumental problems due to the sample matrix, it was shown that solid-phase microextraction (SPME) is effective for the absorption of both the carboxylic acid (RCOOH) and PTMAH permitting on-line methylation from the fiber. A comparison of three fibers, polydimethylsiloxane (PDMS), polyacrylate (PA), and carboxene/PDMS for decanoic and stearic acids showed the carboxene/PDMS fiber was about five times more effective for the extraction of the RCOOH-PTMAH mixture dissolved in methanol. The optimum fiber absorption time was about 20 min and the optimum desorption time in the injection port held at 280 degrees C was about 5-10 min. The optimum PTMAH/RCOOH ratio was about 125:1. Linearity for C18:0 at 3.3 x 10(-6)-3.3 x 10(-4) M was demonstrated by GC-MS with a detection limit of 1 microM. This SPME method is also effective for the methylation of C18:1, C18:2, and C18:3 fatty acids. Transesterification of olive oil using PTMAH and then on-line methylation either by the syringe method or by SPME gave comparable fatty acid methyl ester profiles.