Ederson R. Abaide

Production of Copper and Cobalt Aluminate Spinels and Their Application As Supports for Inulinase Immobilization

Copper and cobalt aluminates were obtained through the use of chitosan as template. In this synthesis route, chitosan is eliminated by heating, and a porous material is produced. These oxides were used as supports for inulinase immobilization by adsorption process. Physical properties of produced particles were analyzed by X-ray diffraction (XRD) and nitrogen adsorption-desorption isotherms. Both oxides presented particles containing mesoporous characteristics and high surface area, which is desirable for applications in enzyme immobilization processes. The results revealed that the copper and cobalt aluminates exhibit high inulinase immobilization efficiencies, which makes them promising supports for enzyme immobilization.

Preparation of Zinc Tungstate (ZnWO4) Particles by Solvo-hydrothermal Technique and their Application as Support for Inulinase Immobilization

ZnWO4 particles were synthesized as a single-phase by a simple and easy solvo-hydrothermal technique using water-ethylene glycol mixture as solvent, without using surfactant. Physical properties of produced particles were analyzed by X-ray diffraction (XRD), infrared spectroscopy (FTIR), surface area (BET), particles size distribution and atomic force microscopy (AFM). This material was used as support for inulinase immobilization by physical adsorption and the influence of temperature (30 and 50 oC) was evaluated. Material with mesoporous characteristic and with a surface area of 35.5 m2.g-1 was obtained. According to the findings, ZnWO4 present a satisfactory inulinase adsorption, and the better result was 605 U.g-1 support at 30 oC. Therefore, ZnWO4 particles prepared by one-step solvo/hydrothermal route provide a new potential support for inulinase immobilization.

Obtaining fermentable sugars and bioproducts from rice husks by subcritical water hydrolysis in a semi-continuous mode

This work aimed at producing fermentable sugars and bioproducts from rice husks by subcritical water hydrolysis at 25 MPa in a semi-continuous mode. The influences of temperature (180 °C; 220 °C; 260 °C) and liquid/solid ratio (7.5 g water/g husks; 15 g water/g husks) on reducing sugar yield (YRS), efficiency (E), kinetic profiles (0-15 min), composition of sugars, inhibitors and organic acids, and physicochemical characteristics of the remaining solid material were evaluated and discussed in the work. The highest YRS (18.0 ± 2.9 g/100 g husks) and E (39.5 ± 1.7 g sugars/100 g carbohydrates) were obtained at 220 °C and 7.5 gwater/g husks. In such condition, the hydrolyzed solutions presented cellobiose (18.0 g/L), xylose 17.7 g/L), arabinose (3.6 g/L), glucose (1.5 g/L), and levulinic acid (0.7 g/L). The fermentable sugars and bioproducts can be applied in several industrial fields, especially for the production of bioethanol and other higher value-added chemical compounds.