|318-3||Characterization of partially purified Penicillium glabrum xylanase using brewer’s spent grain as substrate|
|Autores:||Adriana Knob (UNICENTRO - Universidade Estadual do Centro-Oeste) ; Rosilene Rebeca (UNICENTRO - Universidade Estadual do Centro-Oeste) ; Alex Fernando de Almeida (UNESP - Universidade Estadual Paulista) ; César Rafael Fanchini Terrasan (UFSCAR - Universidade Federal de São Carlos) |
In recent years, xylanases have received attention due to their potential application in biotechnology. As well as other enzymes, industrial production of xylanases on large scale is associated mainly with substrate. The use of agro-industrial residues as low-cost substrates for the industrial enzymes production is a significant way to reduce production cost. Brewer’s spent grain (BSG), the main residue of brewing industry, is rich in cellulose and non-cellulosic polysaccharides. In Brazil, the world’s fourth largest beer producer (8.5 billion litres/year) approximately 1.7 million tonnes of BSG were generated per year. Although the large amounts produced, BSG has received little attention as a low-cost by-product and its use is still limited, mainly as animal feed. This work aimed to partially purified and biochemically characterize the xylanase produced by Penicillium glabrum using brewer’s spent grain as substrate. Xylanase activity was assayed at 50 °C using 1.0 % (w/v) birchwood xylan in McIlvaine buffer pH 6.5. The reducing sugars released were quantified by the dinitrosalicylic acid method, using xylose as standard. After ammonium sulfate fractionation, the partially purified enzyme was characterized by native PAGE and SDS-PAGE and presented 18.65 kDa molecular weight. The optimum activity was observed at 60 ºC, in pH 3.0. The enzyme was very stable at 50 ºC, with half-life of 150 min. High pH stability was verified from pH 2.5 to 5.0. The ion Mn2+ and the reducing agents β-mercaptoethanol and DTT enhanced xylanase activity, while the ions Hg2+, Zn2+ and Cu2+, as well as the detergent SDS were strong inhibitors of the enzyme. This enzyme presented interesting characteristics for biotechnological process such as for animal feed, and in juice and wine industries. The use of brewer’s spent grain, an abundant and low-cost residue, as substrate for fungal growth and xylanase production can not only add value and decrease the amount of this waste, but also substantially reduce the xylanase production cost.
Palavras-chave: Biochemical properties, Filamentous fungi, Xylanolitic enzymes