RESUMO
Xylanases have raised interest because of their potential applications in various industrial fields, including the pulp and paper industries, bioethanol production, and the feed industry. In bioethanol production from lignocellulosic compounds, xylanase can improve the hydrolysis of cellulose into fermentable sugars, since the xylan restricts the cellulases from acting efficiently. In this work, a new thermophilic Streptomyces sp. was selected for its ability to produce xylanase. Carbon source selection is an important factor in the production of hemicellulases. The highest activity was obtained when Streptomyces sp. I3 was grown in the presence of wheat bran. Xylanase activity was partially characterized concerning the effect of pH and temperature on activity and thermostability, and the effects of different metal ions were also tested. The pH and temperature profile showed optimal activity at pH 6.0/70 °C. Zymogram analysis showed multiple xylanases (39, 21, 18, and 17 kDa). Xylanases studied in this work are thermophilic, thermostable, and active in a wide pH range; they have potential to be used in the development of new processes of biotechnological interest.