| Title | A Specific Short Dextrin-Hydrolyzing Extracellular Glucosidase from the Thermophilic Fungus Thermoascus aurantiacus 179-5 |
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| Author | Ana Flavia Azevedo Carvalho, Aline Zorzetto Gonclves, Roberto da Silva, and Eleni Gomes* |
| Address | Laboratory of Biochemistry and Applied Microbiology, IBILCE, Sa˝o Paulo State University, Brazil. |
| Bibliography | Journal of Microbiology, 44(3),276-283, 2006, |
| DOI | |
| Key Words | glucosidase, Thermoascus, submerged fermentation, solid-state fermentation, thermophilic, thermostable |
| Abstract | The thermophilic fungus Thermoascus aurantiacus 179-5 produced large quantities of a glucosidase which preferentially hydrolyzed maltose over starch. Enzyme production was high in submerged fermentation, with a maximal activity of 30 U/ml after 336 h of fermentation. In solid-state fermentation, the activity of the enzyme was 22 U/ml at 144 h in medium containing wheat bran and 5.8 U/ml at 48 h when cassava pulp was used as the culture medium. The enzyme was specific for maltose, very slowly hydrolyzed starch, dextrins (2-7G) and the synthetic substrate (α-PNPG), and did not hydrolyze sucrose. These properties suggest that the enzyme is a type II α-glucosidase. The optimum temperature of the enzyme was 70?. In addition, the enzyme was highly thermostable (100% stability for 10 h at 60? and a half-life of 15 min at 80?), and stable within a wide pH range. |
| Download PDF | JM2005-150.pdf |