Kinetic modeling and optimization of the mono- and diglycerides synthesis mediated by the lipase Lipozyme® TL 100 L immobilized on clayey support.

Mono- and diglycerides play a crucial role in the food industry as multifunctional food additives and emulsifiers. Their importance stems from their unique properties, which allow them to improve the quality, texture, and stability of various food products. Here, results of the kinetic modeling of the mono- and diglycerides synthesis mediated by the lipase Lipozyme® TL 100 L immobilized on the clayey support Spectrogel® type C are reported. The support was characterized by TEM, SEM, and FTIR. Firstly, the influence of pH and lipase load on the immobilization process was analyzed, resulting in an enzymatic activity of 93.2 ± 0.7 U g-1 under optimized conditions (170.9 U g-1 of lipase and pH of 7.1). Afterward, the effects of reaction temperature and concentration of immobilized biocatalyst in the feedstock conversion were evaluated. At optimized parameters, a triglycerides conversion of 97% was obtained at 36.5 °C, 7.9 vol.% of enzyme, a glycerol to feedstock molar ratio of 2:1, and 2 h. The optimized conditions were used to determine the kinetic constants of the elementary reactions involved in the glycerolysis, where a fit superior to 0.99 was achieved between experimental values and predicted data.

Leishmanicidal, Trypanocidal and Antioxidant Activity of Amyrin-Rich Extracts from Eugenia pyriformis Cambess.

AIMS: This study aimed to characterize and evaluate leishmanicidal and trypanocidal action as well as cytotoxicity on macrophages and antioxidant ability of extracts, obtained by supercritical CO2 and ultrasound-assisted extractions of Uvaia (Eugenia pyriformis) leaves. METHODS: Leaves from E. pyriformis were submitted to supercritical CO2 (E1) and ultrasound-assisted (E2) extractions. The characterization of extracts was done using GC-MS and HPLC. L. amazonensis (promastigotes) and T. cruzi (epimastigotes and trypomastigotes) were treated with crescent concentrations of E1 and E2. After this, parasites were counted and the percentage of inhibition and IC50/LC50 was calculated. Murine macrophages were treated with both extracts for 48 h and after that, the cellular viability was determined and CC50 was calculated. DPPH method was used to determine the antioxidant capacity of both extracts. RESULTS: The results of identification showed a great amount of α and ß-amyrin in E1 and E2. Both extracts showed growth inhibition of L. amazonensis with an IC50 of 5.98 and 9.38 µg/mL to E1 and E2, showing a selectivity index > 30. In trypanocidal tests, an LC50 of 16.69 and 7.80 µg/mL (trypomastigotes) and IC50 of 5.56 and 34.34 µg/mL (epimastigotes) was reached by E1 and E2. Both extracts showed no toxicity to macrophages and an antioxidant capacity similar to the positive control (tocopherol). CONCLUSIONS: This is the first study demonstrating the activity of an amyrin rich-extract against microorganisms that cause Chagas disease and leishmaniasis, as well as its antioxidant capacity, justifying further studies for future in - vivo tests.

Biosorption of nickel(II) and copper(II) ions from synthetic and real effluents by alginate-based biosorbent produced from seaweed Sargassum sp.

In this study, the alginate-based biosorbent produced from seaweed Sargassum sp. was used in biosorption of Ni2+ and Cu2+ ions from synthetic solutions and real electroplating effluents. Biosorption kinetics, isotherms, pH effect, thermodynamic parameters, and sorption/desorption cycles were also evaluated. Kinetic studies show the sorption equilibrium can be obtained within 180 min for Ni2+ ions and 360 min for Cu2+ ions, and the adsorption kinetics data are well described by the pseudo-second order and diffusion in spherical adsorbents. Langmuir model can be well used to describe the biosorption isotherm data. The maximum sorption capacity (qmax) and Langmuir constant (b) were up to 1.147 mmol g-1 and 1.139 L mmol-1 for Ni2+ ions and 1.640 mmol g-1 and 4.645 L mmol-1 for Cu2+ ions. The calculated thermodynamic parameters (ΔG°, ΔH°, and ΔS°) showed that the biosorption of Ni2+ and Cu2+ ions are predominantly a chemical phenomenon of endothermic nature, favorable, and spontaneous at the temperature ranges of 293-313 K. Partial desorption of the Ni2+ and Cu2+ ions on the biosorbent was achieved using acidic and saline eluents, allowing the biosorbent to be used in new sorption/desorption cycles. EDX analysis suggests an ion exchange mechanism between calcium ions on the biosorbent and target metals. Biosorption of Ni2+ and Cu2+ from real electroplating effluents with high concentrations of light metals becomes highly competitive, decreasing the amount of Ni2+ and Cu2+ ions biosorbed due to the ionic strength effect.

Enzymatic catalyzed palm oil hydrolysis under ultrasound irradiation: diacylglycerol synthesis.

Diacylglycerol (DAG) rich oils have an organoleptic property like that of regular edible oils, but these oils do not tend to be accumulated as fat. Palm oil ranks first in the world in terms of edible oil production owing to its low cost. The aim of this study was to propose a new methodology to produce diacylglycerol by hydrolysis of palm oil using Lipozyme RM IM commercial lipase as a catalyst under ultrasound irradiation. The reactions were carried out at 55 °C with two different methods. First, the reaction system was exposed to ultrasonic waves for the whole reaction time, which led to enzymatic inactivation and water evaporation. Ultrasound was then used to promote emulsification of the water/oil system before the hydrolysis reaction, avoiding contact between the probe and the enzymes. An experimental design was used to optimize the ultrasound-related parameters and maximize the hydrolysis rate, and in these conditions, with a change in equilibrium, DAG production was evaluated. Better reaction conditions were achieved for the second method: 11.20 wt.% (water+oil mass) water content, 1.36 wt.% (water+oil mass) enzyme load, 12 h of reaction time, 1.2 min and 200 W of exposure to ultrasound. In these conditions diacylglycerol yield was 34.17 wt.%.