Synthesis of 2-ethylhexyl oleate catalyzed by Candida antarctica lipase immobilized on a magnetic polymer support in continuous flow.

This study investigated the synthesis of 2-ethylhexyl oleate catalyzed by Candida antarctica lipase immobilized on magnetic poly(styrene-co-divinylbenzene) particles in a continuous packed-bed bioreactor. Runs were carried out in a solvent-free system at 50 °C. The performance of the reactor was evaluated for substrates composed by oleic acid and 2-ethylhexanol at five molar ratios (1:4-4:1), determining its operation limits in terms of substrate flow rate. The system performance was quantified for three different flow rates corresponding to space-time between 3 and 12 h. For each condition, the influence of the space-time in the ester formation, esterification yield and productivity was determined. The molar ratio of acid-to-alcohol interfered, in a remarkable way, in the formation of 2-ethylhexyl oleate and the best performance was attained for substrate at equimolar ratio running at 12 h space-time. Under this condition, average 2-ethylhexyl oleate concentration was 471.65 ± 2.98 g L-1 which corresponded to ester productivity of 23.16 ± 0.49 mmol g-1 L-1 h-1. This strategy also gave high biocatalyst operational stability, revealing a half-life time of 2063 h. A model based on the ping-pong Bi-Bi mechanism was developed to describe the kinetics of the esterification reaction and validated using experimental data. The goodness of fit of the model was satisfactory (R2 = 0.9310-0.9952).

Non-edible babassu oil as a new source for energy production-a feasibility transesterification survey assisted by ultrasound.

Ethyl esters of babassu oil were synthesized by alkaline catalysis to make the green production of biodiesel feasible with simple methods and available technology. Babassu oil is a transparent, light yellow oil extracted from the seeds of the babassu palm (Orbinya sp), and due to its high saturated fatty acid composition (83%), it is considered a non-inedible oil. Transesterification using ethanol represents a valid alternative to using methanol because of ethanol's lower toxicity and the higher yield on weight compared to methanol. Statistical methodology was applied to optimize the transesterification reaction, which was promoted by ultrasonic waves and mechanical agitation. Nuclear magnetic resonance spectroscopy was used to quantify the conversion attained. Alkaline transesterification assisted by ultrasound produced the best results with respect to reaction time and the phase separation step. The model obtained showed that conversions higher than 97% may be achieved in 10min with correct tuning of the process variables.

Immobilization of a Commercial Lipase from Penicillium camembertii (Lipase G) by Different Strategies.

The objective of this work was to select the most suitable procedure to immobilize lipase from Penicillium camembertii (Lipase G). Different techniques and supports were evaluated, including physical adsorption on hydrophobic supports octyl-agarose, poly(hydroxybutyrate) and Amberlite resin XAD-4; ionic adsorption on the anionic exchange resin MANAE-agarose and covalent attachment on glyoxyl-agarose, MANAE-agarose cross-linked with glutaraldehyde, MANAE-agarose-glutaraldehyde, and epoxy-silica-polyvinyl alcohol composite. Among the tested protocols, the highest hydrolytic activity (128.2 ± 8.10 IU·g(-1) of support) was achieved when the lipase was immobilized on epoxy-SiO(2)-PVA using hexane as coupling medium. Lipase immobilized by ionic adsorption on MANAE-agarose also gave satisfactory result, attaining 55.6 ± 2.60 IU·g(-1) of support. In this procedure, the maximum loading of immobilized enzyme was 9.3 mg·g(-1) of gel, and the highest activity (68.8 ± 2.70 IU·g(-1) of support) was obtained when 20 mg of protein·g(-1) was offered. Immobilization carried out in aqueous medium by physical adsorption on hydrophobic supports and covalent attachment on MANAE-agarose-glutaraldehyde and glyoxyl-agarose was shown to be unfeasible for Lipase G. Thermal stability tests revealed that the immobilized derivative on epoxy-SiO(2)-PVA composite using hexane as coupling medium had a slight higher thermal stability than the free lipase.