Sistemas reacionais ultrassônicos e irradiação por microondas para pré-tratamento de resíduos agroindustriais e incremento de atividade de queratinases

Abstract

Keratinous residues such as swine hair and chicken feathers are generated in large quantities in industrial processes and because of this they are difficult to manage because the presence of keratin. Keratinases are enzymes with a high potential to hydrolyze keratin, emerging as a promising alternative in biotechnological processes. In this sense, the objective of this work was to verify the potential of pretreatment of agro-industrial residues by ultrasonic probe and to evaluate the behavior of the keratinases activity exposed to different ultrasonic reaction systems and by microwave irradiation and subjected to the enzymatic concentration technique from enzymatic extracts produced with swine hair. In addition to comparing the activity of homemade enzymes with commercial enzymes and applying the enzymatic extracts in the degradation of keratinous residues. For this, submerged fermentation was performed with swine hair pretreated with and without ultrasonic probe, for comparative purposes. Then, the enzymatic extracts were exposed to the ultrasonic probe and bath reaction systems and microwaves, according to experimental planning. The enzymatic extracts obtained were submitted to enzymatic concentration with NaCl and acetone and to the evaluation of the potential for degradation of keratinous residues such as swine hair and chicken feathers. The results obtained show that the ultrasonic probe showed a potential for pretreatment of keratinous residues, with a degradation of 45.5% for swine hair pretreated with the macropoint and an increase in reaction rates, producing good values of enzymatic activity in less time (50.8 U/mL in 3 days). In the evaluation of the behavior of keratinases exposed the reaction systems, the ultrasonic probe showed a greater potential for increasing enzyme activity, reaching up to 38.4% increase in enzyme activity, in the shortest exposure time evaluated. The ultrasonic bath showed an increase of 30.2% and microwaves up to 15.1%, both under conditions of high temperature (80 °C). The enzymatic concentration technique with NaCl and acetone showed a potential for significant activity increase of 53.5%. In the degradation of keratinous residues, homemade enzymatic extracts have shown promise in the degradation of chicken feathers, achieving almost total degradation of waste, while swine hair has not shown visual degradation. With that, it is concluded that the results obtained in this work are promising, since the data in this area are scarce, mainly with regard to the use of reaction systems together with keratinases.