Temperature and carbon source affect the production and secretion of a thermostable β-xylosidase by Aspergillus fumigatus |
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Authors: | Veridiana Lenartovicz Cristina Giatti Marques de Souza Fabiana Guillen Moreira Rosane Marina Peralta |
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Affiliation: | Departamento de Bioquímica, Universidade Estadual de Maringá, 87017-900, Maringá, Brazil |
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Abstract: | The effect of the temperature of growth and carbon source on the production and secretion of β-xylosidase (EC 3.2.1.37) by the thermotolerant fungi Aspergillus fumigatus was studied in submerged cultures. In cultures developed at optimal temperature (30 °C), the enzyme was predominantly cell-bound, while in cultures developed at higher temperature (42 °C), the β-xylosidase activity was predominantly found in the cell-free filtrates. The use of corn cob powder instead of xylan as substrate increased considerably the secretion of enzyme. The highest level of extracellular β-xylosidase (45 U/ml or 360 U/mg protein) was obtained in 3% corn cob cultures grown at 42 °C for 72 h. The partially purified enzyme was active and stable at high temperatures. The presence of high titres of β-xylosidase activity in association with xylanase in the culture filtrates enhanced the efficiency of the pulp hydrolysis process. |
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Keywords: | Aspergillus fumigatus Extracellular β-xylosidase Protein secretion Thermostability Xylanolytic enzymes |
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