Purification and characterization of a new Xylanase from Humicola grisea var. Thermoidea

Brazilian Journal of Microbiology

Severino De Albuquerque Lucena-neto¹  Edivaldo Ximenes Ferreira-filho¹ 

[1] ,Universidade de Brasília Departamento de Biologia Celular Laboratório de EnzimologiaBrasília DF ,Brasil

关键词: Humicola grisea;    xylan;    xylanase;    Humicola grisea;    xilana;    xilanase;   

DOI  :  10.1590/S1517-83822004000100014

来源: SciELO

【 摘 要 】

The thermophilic fungus Humicola grisea var. thermoidea secretes extracellular xylanase when grown on solid and in liquid media containing wheat bran and banana plant residue as substrates, respectively. At 55ºC, xylanase from the culture filtrate of H. grisea var. thermoidea grown on banana stalk retained 50% of its activity after 28 h of incubation. A xylanase (X2) was isolated from solid state cultures with wheat bran as the carbon source. It was purified to apparent homogeneity by ultrafiltration followed by ion-exchange and hydrophobic interaction chromatography on DEAE-Sepharose and Phenyl-Sepharose resins, respectively. The enzyme had an apparent molecular weight of 29 kDa, as determined by SDS-PAGE. The purified enzyme was most active at pH and temperature ranges of 4.5-6.5 and 55-60ºC, respectively. In addition, X2 showed thermostability at 60ºC with a half-life of approx. 5.5 h. The apparent Km values, using soluble and insoluble arabinoxylans as substrates, were 10.87 and 11.20 mg/ml, respectively.

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