Produção, purificação, caracterização e aplicação de tanase de Aspergillus melleus URM 5827 produzida por fermentação em estado sólido utilizando sementes de achachairú (Garcinia humilis (Vahl) C. D. Adam)

Abstract

Tannin acylhydrolase (TAH) known as tannase (E.C:3.1.1.20) is an enzyme which hydrolizes esters and lateral bonds of hydrolizable tannins. The tannic acid is a typical hydrolizable tannin, which can be hydrolized by tannase along with glucose and gallic acid. Tannase can be obtained from vegetables, animal and microbial sources. From those, the last is the most important source to obtain the enzyme. Green tea has several substances, among which catechins are a major source of antioxidant, which help in maintaining the organism.The activity and purification of tannase produced by Aspergillus melleus URM 5827 was evaluated by semi solid fermentation using seeds of mangosteen (Garcinia humilis (Vahl) C. D. Adam) as substract. Forty two cultures fungical cultures of Aspergillus were used for qualitative selection purposes in order to verify potential for tannase production. After selecting cultures, it was performed a semi solid fermentation using seeds of mangosteen as substrate. A factorial planning (2³) was used to verify the influence of production variables such as: quantity of substrate; initial moisture and amount of tannic acid over tannase activity. The purification was evaluated by ionic change chromatography at DEAE-Sephadex. Maximum activity was produced by Aspergillus melleus URM 5827 with 452.55 units per gram of dry-based substract (U/gss) using 5.0 grams of substrate, with initial moisture of 60% and 2% of tannic acid through 48 hours fermentation. The purified enzyme has a molecular weight of 69.52 kDa on Superdex G-75, while on SDS-PAGE electrophoresis showed 66.5 kDa. As for the characterization, the optimum pH and temperature was 5.5 and 40ºC, respectively, achieving thermostability at 30ºC. Coughing increases the antioxidant activity of green tea significantly. The results obtained in this study show the promising potential of tannase produced by Aspergillus melleus URM 5827 and its use in improving the antioxidant potential of green tea.