The liquid product of the pyrolysis of biomass is a mixture of an organic phase and other aqueous, being the last one rich in phenol monomers which can be used in industrial chemistry as input for plastic and resin production. This work aimed to develop a method for extracting phenols present in the aqueous fraction obtained from the pyrolysis of guava seeds, using ultrasonic assisted liquid-liquid extraction (UALLE) with ethyl acetate and ionic liquids (ILs) as co-solvents (1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) amide (BMIM.NTF2) and 1-butyl-3-methylimidazolinium hexafluorophosphate (BMIM.PF6)). The percentage IL, ultrasonic bath potency, temperature, and pH were studied. Quantification of twelve phenol monomers was performed using gas chromatography-mass spectrometry (GC-MS) and the total phenol concentration (TPC) was performed using UV-Vis spectrophotometer. The ionic liquid BMIM.NTF2 was more efficient for phenol extraction than BMIM.PF6. The phenolic extractions were influenced by the pH of the aqueous fraction (higher extraction yields at pH ≤ 7), and thus, presented recoveries above 80% for both ionic liquids.

The immobilization of horseradish peroxidase (HRP) on raw and alkaline pre-treated sugarcane bagasse by physical adsorption (ADS) and covalent bond (LC) methods was studied. The saturation of the support with 2 mg of HRP/g of support by LC immobilization reached 35% of immobilization efficiency and 39 units of the immobilized enzyme (U). Regarding the HRP immobilization on sugarcane bagasse without pretreatment and using the same HRP loading, it was observed a reduction in the efficiency of immobilization and in the number of immobilized units for both methods, ADS (13.98% and 15.46 U) and LC (15.79% and 17.46 U). The sugarcane bagasse with alkaline pretreatment experiment, on the other hand, exhibited higher potential for HRP immobilization by LC. The supports and biocatalysts were characterized by Fourier transform infrared spectroscopy (FTIR), showing greater availability of hydroxyl groups in the pretreated support and the typical amide I and amide II bands that corroborate the effectiveness of the enzyme immobilization on sugarcane bagasse. In the same way, the thermogravimetric analysis (TGA) confirmed a higher weight loss in the region I for the derivative immobilized by LC, suggesting the presence of water favored enzymatic activity.

Mesoporous silica supports (aerogels) were used to immobilize Burkholderia cepacia lipase (BC) by encapsulation (EN or ENIL), physical adsorption (ADS or ADSIL) and covalent binding (CB or CBIL) into or onto the aerogel modified with protic ionic liquid (PIL). Yield immobilization (Ya) and operational stability were determined by the hydrolytic reaction of olive oil. Ya (37% to 83% by physical adsorption) and operational stability (2 to 23 batches by encapsulation) increased when the support was modified with PIL. For immobilized derivates observed by the BET method, in this case ADS and CB for ADSIL and CBIL, increased pores size was observed, possibly due to the higher amount of BC immobilized conferring Ya and operational stability. This effect was probably attributed to the entry of the enzyme into the pores of the silica aerogel structure. SEM images showed a change in the structure and properties of immobilized lipase derived with PIL. A characteristic FTIR band was obtained for the silanol groups and amides I, IV and V, demonstrating the efficiency of immobilization of BC. The most efficient biocatalysts were ADSIL with regard to yield immobilization and ENIL for operational stability.

This work investigated the effect of microwave irradiation (MW) on the ethanolysis rate of soybean and sunflower oils catalyzed by supported Novozyme 435 (Candida antarctica). The effects of tert-butanol, water addition and oil:ethanol molar ratio on transesterification were evaluated under conventional heating (CH), and under optimum reaction conditions (with no added water in the system, 10% tert-butanol and 3:1 ethanol-to-oil molar ratio). The reactions were monitored up to 24 h to determine the conditions of initial reaction velocity. The investigated variables under MW (50 W) were: reaction time (5.0-180 min) and mode of reactor operation (fixed power, dynamic and cycles) in the absence and presence of tert-butanol (10% (w/w). The measured response was the reaction conversion in ethyl esters, which was linked to the enzyme catalytic activity. The results indicated that the use of microwave improved the activity at fixed power mode. A positive effect of the association of tert-butanol and MW irradiation on the catalytic activity was observed. The reaction rate improved in the order of approximately 1.5 fold compared to that under CH with soybean oil. Using soybean oil, the enzymatic transesterification under MW for conversion to FAEE (fatty acid ethyl esters) reached >99% in 3h, while with the use of CH the conversions were about 57% under similar conditions.

Enzyme-support strategies are increasingly replacing conventional chemical methods in both laboratories and industries with attributes including efficiency, higher performance and multifarious use, where silica surfaces show potential due to the chemical bonds based on the presence of hydroxyl groups which can be modified with different additives. Surface-modified silica is a novel class of materials capable of improving enzyme stability and reusability that can be applied to support several immobilization techniques. This review describes the use of innovative modified supports to improve the state of enzyme immobilization and provide the industrial sector with new perspectives.

Lipase from Burkholderia cepacia was immobilized in a silica matrix and dried in high pressure carbon dioxide media (aerogel). The protic ionic liquid (PIL) was used in the immobilization process by encapsulation. The objective of this work was to evaluate the influence of the drying technique using supercritical carbon dioxide in biocatalysts obtained through the sol-gel technique by evaluating temperature and pressure and, after selecting the best drying conditions, to investigate the application of the technique for the biocatalyst using ionic liquid as an additive in the immobilization process. The results for immobilized biocatalysts showed that the best conditions of pressure and temperature were 100 bar and 25 ºC, respectively, giving a total activity recovery yield of 37.27% without PIL (EN) and 44.23% with PIL (ENLI). The operational stability of the biocatalysts showed a half-life of 11.4 h for ENLI and 6 h for EN. Therefore, solvent extraction using supercritical CO2, besides shortening drying time, offers little resistance to the immobilization of lipases, since their macropores provide ample room for their molecules. The use of the ionic liquid as an additive in the process studied for the immobilization of enzymes produced attractive yields for immobilization and therefore has potential for industrial applications in the hydrolysis of vegetable oils.

A síntese orgânica catalisada por enzimas envolve um mecanismo complexo dependente do tipo de substrato, enzima, solvente orgânico e teor de água no meio reacional. Neste trabalho foi estudado a influência de alguns desses parâmetros no rendimento da esterificação do butanol com ácido butírico, utilizando uma preparação enzimática comercial de lipase. A polaridade e natureza do solvente, bem como a razão molar entre o butanol e ácido butírico, foram considerados os fatores que mais influenciaram o desenvolvimento dessa síntese enzimática.

The organic synthesis catalyzed by enzymes is a complex function of substrate concentration, water concentration in the liquid phase, enzyme and organic solvent properties. In this work the influence of some parameters on the esterification of butanol with butyric acid was investigated, using a commercial lipase preparation. The polarity and nature of the solvent and also the substrate mole ratios played an important role in the performance of this enzymatic synthesis.