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In this work, a "green" Aspergillus niger lipase obtained from the solid-state fermentation of Hancornia speciosa ("mangaba") seeds was efficiently immobilised on polyethersulfone membranes (PES) by physical adsorption (PES-ADS-lipase) and covalent bonding (PES-COV-lipase) (immobilisation yields of 92 and 81%, respectively). The free lipase showed an optimum pH close to neutrality, while the biocatalysts displaced the pH to the alkaline region (optimum pH 9.0 and 11.0 for PES-ADS-lipase and PES-COV-lipase, respectively). The optimum temperature of free lipase was 55°C; however, a higher thermal stability occurred at 37°C. The PES-ADS-lipase and PES-COV-lipase showed lower optimum temperatures (37 and 45°C, respectively) but higher thermal stabilities at 45 and 55°C, respectively. The lower thermal inactivation constant and higher half-life of PES-COV-lipase at 55°C confirmed the efficiency of covalent bonding in maintaining the thermal stability of the enzyme. The Michaelis–Menten constant (Km) and maximum rate of reaction (Vmax) were also determined, and the biocatalysts showed higher affinities to substrates (lower Km values) than free lipase. In this work, the biocatalysts showed good catalytic properties with future potential applications in hydrolysis reactions. The use of a "green" lipase obtained from agroindustrial residue makes this product economically attractive from an industrial point of view. [ABSTRACT FROM AUTHOR]

In this work, a "green" Aspergillus niger lipase obtained from the solid-state fermentation of Hancornia speciosa (“mangaba") seeds was efficiently immobilised on polyethersulfone membranes (PES) by physical adsorption (PES-ADS-lipase) and covalent bonding (PES-COV-lipase) (immobilisation yields of 92 and 81%, respectively). The free lipase showed an optimum pH close to neutrality, while the biocatalysts displaced the pH to the alkaline region (optimum pH 9.0 and 11.0 for PES-ADS-lipase and PES-COV-lipase, respectively). The optimum temperature of free lipase was 55°C; however, a higher thermal stability occurred at 37°C. The PES-ADS-lipase and PES-COV-lipase showed lower optimum temperatures (37 and 45°C, respectively) but higher thermal stabilities at 45 and 55°C, respectively. The lower thermal inactivation constant and higher half-life of PES-COV-lipase at 55°C confirmed the efficiency of covalent bonding in maintaining the thermal stability of the enzyme. The Michaelis-Menten constant (Km) and maximum rate of reaction (Vmax) were also determined, and the biocatalysts showed higher affinities to substrates (lower Km values) than free lipase. In this work, the biocatalysts showed good catalytic properties with future potential applications in hydrolysis reactions. The use of a “green" lipase obtained from agroindustrial residue makes this product economically attractive from an industrial point of view. [ABSTRACT FROM AUTHOR]

Copyright of Acta Scientiarum: Technology is the property of Universidade Estadual de Maringa and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Scientiarum: Technology is the property of Universidade Estadual de Maringa and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Scientiarum: Technology is the property of Universidade Estadual de Maringa and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work investigated the effect of different extracting agents on the extraction of phenolic compounds from agro-industrial residues of seriguela. Additionally, the phenolic compounds partitioning was studied using aqueous two-phase systems based on the extracting agents. The effect of the type of extracting agent such as water, organic solvent (1,3-dioxolane, acetone, 1,4-dioxane, and acetonitrile), and different ionic liquids (ILs) was evaluated. Afterward, solvent concentration, solid-liquid ratio, and time were analyzed in the extraction process. The solvent polarity played an important role in the extraction; thus 1,3-dioxolane (20 wt%), solid-liquid ratio 1:10 for 45 min was the best condition presented for organic solvents (1437.00 ± 0.01 mg L-1). On the other hand, [C2mim][CH3SO3] (20%), liquid-solid ratio 1:10 for 10 min was the best condition using IL (1842.56 ± 42.43 mg L-1). The mixture of water (60 wt%) + 1.3 dioxolane (20 wt%) + [C2mim][CH3SO3] (20 wt%) increased the concentration of phenolic compounds to 1894.22 ± 90.51 mg L-1. The phase separation was performed with the addition of organic solvent, reaching the mixture composition of 1,3-dioxolane (40 wt%) + [C2mim] [CH3SO3] (10 wt%) + water (50 wt%) at 25 °C, allowing the recovery of the phenolic compounds (98.63 ± 0.15%) to the bottom phase (IL-rich phase) and a partition coefficient of 0.0092 ± 0.0002. [ABSTRACT FROM AUTHOR]

In this study, ascorbic acid and vanillin were recovered using semi-continuous and continuous operation of an aqueous two-phase system (ATPS) formed by ethanol (C2H5OH) and dipotassium hydrogen phosphate (K2HP04). For operation, a column reactor was designed, allowing temperature control by a coating system and the circulation of up to two phases simultaneously. The reactor was equipped with a stirring system composed of a shaft and impellers known as vanes. In the experiments, the influence of volumetric flow rate and agitation speed were analysed to enhance recovery of the biomolecules of interest. The best recovery values were obtained in semi-continuous operation at low rotations (60 rpm) and high volumetric flow rate (6.0 mL min-1). These parameters were used to verify partitioning using a real food matrix (Dr. Oetker Diet Pudding), achieving recovery of up to 94% for vanillin in the top phase and ascorbic acid in the bottom phase. [ABSTRACT FROM AUTHOR]

In this work it is shown, for the first time, that aqueous solutions of poly(vinyl alcohol) (PVA) and acetonitrile (ACN) undergo liquid-liquid demixing and form aqueous two-phase systems (ATPS). The ternary phase diagrams composed of PVA of different molecular weights, namely 9000-10,000, 13,000-23,000, 31,000-50,000 g mol-1 and 85,000-124,000 g mol-1, acetonitrile and water, and the respective tie-lines were determined at 25 ° C. In all the systems investigated, ACN is enriched in the top phase while PVA is found in the bottom phase. To explore the potentiality of these ATPS for extraction strategies, the partitioning of vanillin among the coexisting phases was further evaluated. The effects of ACN and PVA concentrations and temperature toward the vanillin partitioning were also investigated. An increased vanillin partitioning to the top phase was verified with the increase of the ACN concentration; however, the partition coefficient of vanillin for the ACN-rich phase decreases with the increase on both the PVA concentration and temperature. The highest partition coefficient of vanillin for the ACN-rich phase (2.24) was found with the system composed of 49wt% of ACN + 9wt% of PVA 9000-10,000 g mol-1 at 5°C, with a recovery of 79%. The vanillin migration to the top phase is spontaneous and an exothermic process. [ABSTRACT FROM AUTHOR]

The use of lipases in industrial processes can result in products with high levels of purity and at the same time reduce pollutant generation and improve both selectivity and yields. In this work, lipase from Thermomyces lanuginosus was immobilized using two different techniques. The first involves the hydrolysis/polycondensation of a silica precursor (tetramethoxysilane (TMOS)) at neutral pH and ambient temperature, and the second one uses tetraethoxysilane (TEOS) as the silica precursor, involving the hydrolysis and polycondensation of the alkoxide in appropriate solvents. After immobilization, the enzymatic preparations were dried using the aerogel and xerogel techniques and then characterized in terms of their hydrolytic activities using a titrimetric method with olive oil and by the formation of 2-phenylethyl acetate in a transesterification reaction. The morphological properties of the materials were characterized using scanning electron microscopy, measurements of the surface area and pore size and volume, thermogravimetric analysis, and exploratory differential calorimetry. The results of the work indicate that the use of different silica precursors (TEOS or TMOS) and different drying techniques (aerogel or xerogel) can significantly affect the properties of the resulting biocatalyst. Drying with supercritical CO2 provided higher enzymatic activities and pore sizes and was therefore preferable to drying, using the xerogel technique. Thermogravimetric analysis and differential scanning calorimetry analyses revealed differences in behavior between the two biocatalyst preparations due to the compounds present.