Abstract Previous studies have investigated the preparation of heterogeneous biocatalysts based on the immobilization of lipases on distinct types of supports. However, few works have investigated the influence of the textural properties of these supports on the immobilization parameters. Thus, the present article reports the preparation of copolymers based on divinylbenzene by aqueous suspension polymerizations, using different amounts of porogenic agents to prepare particles with distinct textural properties. The particles were used for immobilization of lipase from Candida antarctica fraction B and the performance of the biocatalysts was evaluated in hydrolysis reactions, using p-nitrophenyl laurate as substrate. The use of Sty/DVB particles resulted in higher immobilization yields (89.5% and 99.2%) and higher hydrolytic activities, when compared to the Sty/VBC/DVB particles. Particularly, the increase of the pore diameters of the particles resulted in higher immobilization yields. Also, the hydrolytic activities depended simultaneously on the average pore diameter, porosity, and specific area (the most influential variable) of the supports. Thus, it was observed that the distinct morphological features of the polymer support can exert significant and conflicting effects on the final biocatalyst performance, since the specific surface area is normally expected to decrease with the increase of the average pore size.

The flavonoid rutin presents several pharmacological effects, despite this, its application in the pharmaceutical industry can be significantly limited by its low bioavailability. The development of lipophilic derivatives by esterification of hydroxyl groups with fatty acid chains may be an effective strategy to change their physicochemical properties. This work aims to use high-speed countercurrent chromatography (HSCCC) to isolate rutin esters produced by esterification reactions catalyzed by the immobilized lipase from Candida antarctica (Novozyme 435®). The lipase-catalyzed synthesis of rutin esters (R3-R18:2) in 2-methyl-2-butanol exhibited conversions that ranged from 16 to 40% and highest conversion for short chain fatty acids (R4-R12). After initial partitioning tests of the reaction mixture in different solvent proportions followed by thin layer chromatography (TLC) analysis, the biphasic solvent systems consisting in HEMWat (hexane/ethyl acetate/methanol/water) in different proportions were chosen to separate rutin esters. These esters were separated for the first time to the reaction mixture via HSCCC. This technique proved to be more advantageous than the traditionally one since it allowed quick isolation and high purity (≥ 90%) of the products. It also permitted a substrate recovery for reuse in other enzymatic reactions. Furthermore, the results add valuable information, specially concerning the structures elucidation of different rutin esters not previously described.

The present work studied aqueous extracts of castor beans as a natural inhibitor of the corrosion of mild steel in 1 M HCl using gravimetric tests, potentiodynamic polarization curves, linear polarization method, electrochemical impedance measurements, surface analysis by scanning electron microscopy (SEM) and chemical characterization by Fourier transform infrared spectroscopy (FTIR). Gravimetric tests showed that inhibition efficiency (IE) increased with immersion time and concentration of the extract, reaching 97.8% in the presence of 800 mg L−1 inhibitor after 24 h immersion time. For the gravimetric tests varying the temperature, a decrease of the activation energy (Ea) was observed, suggesting chemical adsorption of extract components on the metal surface. The extracts from the castor beans acted as a good corrosion inhibitor, and the macromolecules present in the high molecular weight fraction (HMWF) have a fundamental participation in this process since it presented 93.7% of IE for 200 mg L−1.

Abstract This study aimed to optimize ultrasound-assisted palm oil-in-water nanoemulsions. The influence of hydrophilic-lipophilic balance (HLB), oil and surfactants concentrations, ultrasound intensity and processing time were investigated by means of two experimental designs. Desirability profiles were applied to detect the optimal conditions for preparing the nanoemulsion. Stable nanoemulsions with small droplet size and polydispersity index (PDI) were obtained at an HLB of 6.5, oil and surfactant concentrations of 2.8 wt%, ultrasound intensity of 200 W.cm-2 and processing time of 15 minutes. The nanoemulsion presented stability for 30 days at three different temperatures (4°C, 25°C and 40°C), which makes it suitable for application in the food and cosmetic industries. Ultrasound was shown to be a promising technology to produce nanoemulsions containing palm oil.

ABSTRACT The combination of 0.5% weight per volume (w/v) crude enzyme consortia produced by solid state fermentation with Penicillium brevicompactum and 27 milligrams per liter (mg/L) of rhamnolipid biosurfactant produced by submerged fermentation with Pseudomonas aeruginosa was employed to pretreat wastewater from a poultry slaughterhouse in bench upflow anaerobic sludge blanket (UASB) bioreactors. One bioreactor was fed with untreated wastewater (Control) and another with pretreated wastewater (Test). Under an organic loading rate of 11 kg COD/m3.d, the Test bioreactor showed higher specific methane production (67.8 mL CH4 (STP)/g COD removed), higher chemical oxygen demand (COD) (91.2%), and oil and grease (O&G) (95.8%) removal than the Control bioreactor, which produced 36.1 - 16.9 mL CH4 (STP)/g COD removed with 72.5% COD removal and 48% O&G removal. The Control bioreactor experienced five clogging episodes due to the accumulation of fat on the surface, while the Test bioreactor operated without operational problems. The scum of the Control bioreactor contained more than 10 times higher quantities of fat than the Test bioreactor. The economic analysis indicated that such alternative technology has lower costs than conventional technology.