Valoração de peroxidases não comerciais visando aplicação em reações de interesse ambiental

Abstract

The enzymes are mainly proteins responsible for catalyze a wide range of biochemical reactions in several living systems and the parameters that most interfere in these reactions are substrate concentration, pH and temperature. Due to advantages such as action in mild environmental conditions, low aggressiveness to the environment and high specificity, enzymes are gaining space in industrial processes. Peroxidase is one of them, presenting the ability to oxidize several substrates in a stable way. The study of enzymatic concentration techniques of non-commercial peroxidases is becoming relevant in order to improve its catalytic properties and to develop environmental interest reactions. Therefore, this work aim to characterize the catalytic properties of rice bran peroxidase (RBP), to evaluate it through concentration techniques and to analyze its insertion in wastewater treatment processes of the textile industry, whose activities cause problems for human and environmental health. In the crude enzyme extract characterization, its resistance was analyzed in different temperature and pH conditions, which demonstrated application possibilities in processes that can occur between 20 and 70°C and in a pH range between 4 and 8 without occurring enzyme denaturation. The highest reduction potential (+0.325 V vs SHE) corresponded to RBP submitted to a pH 5.5 and a temperature 25°C. In this condition, the enzymatic activity had a larger decay within 24 hours of reaction and the redox potential and pH remained practically constant. Then, the enzyme valuation was carried out through enzymatic concentration, being possible to increase the specific enzymatic activity by up to 2.9 times through Aqueous Two-Phase System (ATPS) with polyethylene glycol and sodium chloride and up to 1.9 times through Precipitation with acetone and sodium chloride. The RBP insertion in advanced oxidative processes was also analyzed, creating configurations for its application in synthetic textile effluent with degradation and dye removal purpose. It was possible to obtain up to 100% color removal applying RBP precipitated in shaker system, giving to the textile industries an economically and environmentally viable alternative to treat effluents. Thus, the peroxidase valuation techniques and its application in textile effluent are promising and have the potential to be exploited in industrial processes, since rice bran peroxidase has demonstrated affinity with dyes.