Transesterification of fish oil to produce fatty acid ethyl esters using ultrasonic energy

This study evaluated the production of fatty acid ethyl esters from fish oil using ultrasonic energy and alkaline catalysts dissolved in ethanol. The feasibility of fatty acid ethyl ester production was determined using an ultrasonic bath and probe, and between 0.5 and 1% KOH (added to the fish oil). Furthermore, factors such as ultrasonic device (bath and probe), catalyst (KOH and C2H5ONa), temperature (20 and 60 °C), and duration of exposure (10–90 min) were assessed. Sodium ethoxide was found to be a more efficient catalyst than KOH when transesterifying fish oil. Ultrasonic energy applied for greater than 30 min at 60 °C using 0.8% of C2H5ONa as a catalyst transesterified over 98% fish oil triglycerides to fatty acid ethyl esters. It is reasonable to conclude that the yield of fatty acid ethyl esters produced by applying ultrasonic energy to fish oil is related to the sonication time. Due to increases in the surface area contact between the reactants and the catalyst, ultrasonic energy has the potential to reduce the production time required by a conventional large-scale commercial transesterification method that uses agitation as a way of mixing.

Transesterification induced mechanical properties enhancement of PLLA/PHBV bio-alloy

In order to improve the miscibility and mechanical properties of poly(l-lactic acid) (PLLA) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) bio-alloy, small amount of transesterification catalyst, zinc acetate was added in the melt blending process. We show that the PLLA-PHBV copolymer generated during the melt blending significantly improves the miscibility and therefore enhances the mechanical properties of the product. Dynamic mechanical analysis (DMA), scanning electron microscopy (SEM), and tensile tests were performed to study the miscibility and mechanical properties of the blends. Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC) were used to reveal the molecular structural, and molecular weight changes of PLLA and PHBV after melt mixing with zinc acetate. SEM and FTIR results have clearly shown that the PLLA-PHBV copolymer generated from transesterification reaction acted as a compatibilizer and therefore resulted in an improved interfacial miscibility and ductility of PLLA/PHBV blend. In our mechanistic study, a competition between the PLLA/PHBV transesterification reaction and the thermal decomposition of PHBV was identified for the first time. On the basis of these observations, a new mechanism of transesterification reaction was proposed.

Evaluation of fatty acid extraction methods for Thraustochytrium sp. ONC-T18

Various extraction methods were assessed in their capacity to extract fatty acids from a dried biomass of Thraustochytrium sp. ONC-T18. Direct saponification using KOH in ethanol or in hexane:ethanol was one of the most efficient techniques to extract lipids (697 mg g^-1). The highest amount of fatty acids (714 mg g^-1) was extracted using a miniaturized Bligh and Dyer extraction technique. The use of ultrasonics to break down cell walls while extracting with solvents (methanol:chloroform) also offered high extraction yields of fatty acids (609 mg g^-1). Moreover, when the transesterification mixture used for a direct transesterification method was doubled, the extraction of fatty acids increased approximately 77% (from 392 to 696 mg g^-1). This work showed that Thraustochytrium sp. ONC-T18 has the ability to produce over 700 mg g^-1 of lipids, including more than 165 mg g-1 of docosahexaenoic acid, which makes this microorganism a potential candidate for the commercial production of polyunsaturated fatty acids. Finally, other lipids, such as myristic, palmitic, palmitoleic, and oleic acids, were also produced and recovered in significant amounts (54, 196, 123, and 81 mg g^-1), respectively.

Qualitative and quantitative analysis of lipid classes in fish oils by thin-layer chromatography with an Iatroscan flame Ionization detector (TLC-FID) and liquid chromatography with an evaporative light scattering detector (LC-ELSD)

Combined effects of hydrogen and air flow rates on the peak response of selected neutral lipid classes (triacylglycerol, diacylglycerol, monoacylglycerol, free fatty acids, and ethyl esters) were studied to optimize and calibrate the Iatroscan Mk-6s Chromarod system for the qualitative and quantitative analysis of lipid classes by thin-layer chromatography (TLC) with flame ionization detection in fish oil during the transesterification process. Air flow rate of 2 L/min, hydrogen flow rate of 150-160 mL/min, and scan rate of 30 s/rod were found to be the optimum conditions. All samples were also analyzed by high performance liquid chromatography (HPLC) with evaporative light scattering detection. Quantitative results obtained by TLC with the flame ionization detection method were comparable to those obtained from HPLC with evaporative light scattering detection.

Production of Omega-3 Triacylglycerol concentrates using a new food grade immobilized Candida antarctica Lipase B

Triacylglycerol concentrates of eicosapentaenoic and docosahexaenoic omega-3 fatty acids were synthesized either via transesterification or esterification of glycerol with the corresponding ethyl ester or free fatty acid concentrates, respectively. A newly developed food grade immobilized Candida antarctica lipase Β system using an Amberlite FPX-66 hydrophobic matrix, was compared with a commercially available non-food grade commercial system, for their ability to catalyze these reactions. For either system, the transesterification required higher temperature (90◦C) than esterification (70°C) to achieve maximum triacylglycerol yields. The newly developed immobilized system efficiently catalyzes the esterification of free fatty acids with glycerol and differs from the existing commercial system in that it is food grade and has a more uniform and larger particle distribution. The new system significantly improves flow in a packed bed reactor, enabling multiple reuse of the catalyst for up to 80 repeats.

Synthesis of ethyl acetate employing celite-immobilized lipase of Bacillus cereus MTCC 8372

A wide range of fatty acid esters can be synthesized by esterification and transesterification reactions catalyzed by lipases in non-aqueous systems. In the present study, immobilization of a purified alkaline extra-cellular lipase of Bacillus cereus MTCC 8372 by adsorption on diatomaceous earth (celite) for synthesis of ethyl acetate via transesterification route was investigated. B. cereus lipase was deposited on celite (77% protein binding efficiency) by direct binding from aqueous solution. Immobilized lipase was used to synthesis of ethyl acetate from vinyl acetate and ethanol in n -nonane. Various reaction conditions, such as biocatalyst concentration, substrates concentration, choices of solvents ( n -alkanes), incubation time, temperature, molecular sieves (3Å × 1.5 mm), and water activity(a _w ), were optimized. The immobilized lipase (25 mg/ml) was used to perform transesterification in n -alkane(s) that resulted in approximately 73.7 mM of ethyl acetate at 55 °C in n -nonane under shaking (160 rpm) after 15 h, when vinyl acetate and ethanol were used in a equimolar ratio (100 mM each). Addition of molecular sieves (3Å × 1.5 mm) as well as effect of water activity of saturated salt solutions (KI, KCl and KNO ₃ ) to the transesterification efficiency has inhibitory effect. Batch operational stability tests indicated that immobilized lipase had retained 50% of its original catalytic activity after four consecutive batches of 15 h each.

Microbial lipases : at the interface of aqueous and non-aqueous media: a review

In recent times, biotechnological applications of microbial lipases in synthesis of many organic molecules have rapidly increased in non-aqueous media. Microbial lipases are the working horses' in biocatalysis and have been extensively studied when their exceptionally high stability in non-aqueous media has been discovered. Stability of lipases in organic solvents makes them commercially feasibile in the enzymatic esterification reactions. Their stability is affected by temperature, reaction medium, water concentration and by the biocatalyst's preparation. An optimization process for ester synthesis from pilot scale to industrial scale in the reaction medium is discussed. The water released during the esterification process can be controlled over a wide range and has a profound effect on the activity of the lipases. Approaches to lipase catalysis like protein engineering, directed evolution and metagenome approach were studied. This review reports the recent development in the field of non-aqueous microbial lipase catalysis and factors controlling the esterification/transesterification processes in organic media.

Comparison of cell disruption methods for improving lipid extraction from thraustochytrid strains

Lipid extraction is an integral part of biodiesel production, as it facilitates the release of fatty acids from algal cells. To utilise thraustochytrids as a potential source for lipid production. We evaluated the extraction efficiency of various solvents and solvent combinations for lipid extraction from Schizochytrium sp. S31 and Thraustochytrium sp. AMCQS5-5. The maximum lipid extraction yield was 22% using a chloroform:methanol ratio of 2:1. We compared various cell disruption methods to improve lipid extraction yields, including grinding with liquid nitrogen, bead vortexing, osmotic shock, water bath, sonication and shake mill. The highest lipid extraction yields were obtained using osmotic shock and 48.7% from Schizochytrium sp. S31 and 29.1% from Thraustochytrium sp. AMCQS5-5. Saturated and monounsaturated fatty acid contents were more than 60% in Schizochytrium sp. S31 which suggests their suitability for biodiesel production.

Diesel engine performance and emission study using soybean biodiesel blends with fossil diesel

Biodiesel is an ecofriendly and renewable source of energy which can be used as a sustainable alternative fuel fordiesel engine. The study investigated engine performance and emission using soybean biodiesel blends with fossildiesel. The physio-chemical fuel properties of the biodiesel were determined using ASTM and EN standards. Thebiodiesel was blended in different proportions like 5% biodiesel and 95% diesel (by volume) denoted as B5, similarlyB10, B20 and B50. The biodiesel blends were tested in a multicylinder, diesel engine coupled with electromagneticdynamometer, under ISO 8178-4 test procedure. The study found that the biodiesel blends produces less brakepower, brake torque and relatively higher brake specific fuel consumption compared with diesel fuel. However, thesefules significantly reduces exhaust gases namely, CO, CO2 and HC but emits a bit more NOx compared with diesel.The reduction in emissions were different for each biodiesel blends. The study concluded that both B5 and B10blends are the optimum blends that produce more consistant and expected results compared with other blends.