Studies on a thermostable alpha-amylase from the thermophilic fungus Scytalidium thermophilum

• Published in: Applied microbiology and biotechnology Vol. 61; no. 4; pp. 323 - 328
• Main Authors: Aquino, A.C.M.M, Jorge, J.A, Terenzi, H.F, Polizeli, M.L.T.M
• Format: Journal Article
• Language: English
• Published: Berlin Springer 01.05.2003; Springer Nature B.V
• Subjects: Acids; agarose; alpha-amylase; alpha-Amylases; alpha-Amylases - antagonists & inhibitors; alpha-Amylases - chemistry; alpha-Amylases - isolation & purification; alpha-Amylases - metabolism; Amylases; Amylopectin; Amylose; antagonists & inhibitors; Ascomycota; Ascomycota - enzymology; Biological and medical sciences; calcium; Calcium ions; Carbohydrate Metabolism; Cellulose; chemistry; Chromatography; Copper chloride; Enzyme Activators; Enzyme Activators - pharmacology; Enzyme Stability; Enzymes; enzymology; Fundamental and applied biological sciences. Psychology; Fungi; gel chromatography; Gel electrophoresis; Gel filtration; Glucan; Glucose; Glycogen; Glycogens; half life; Hydrogen-Ion Concentration; Hydrolysis; Ion exchange; Ion exchange chromatography; isolation & purification; Maltose; Mercuric chloride; metabolism; Metal ions; Metals; Metals - pharmacology; Methods; Microbiological chemistry; Microbiology; Molecular Weight; Oligosaccharides; pharmacology; Physiological aspects; polyacrylamide gel electrophoresis; Proteins; Scytalidium; Sodium; Sodium lauryl sulfate; Starch; Starch - metabolism; starch products; Studies; Substrates; Temperature; thermal stability; Thermophilic fungi; Thin layer chromatography; α-Amylase; Brazil
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-003-1290-y

An alpha-amylase produced by Scytalidium thermophilum was purified using DEAE-cellulose and CM-cellulose ion exchange chromatography and Sepharose 6B gel filtration. The purified protein migrated as a single band in 6% PAGE and 7% SDS-PAGE. The estimated molecular mass was 36 kDa (SDS-PAGE) and 49 kDa (Sepharose 6B). Optima of pH and temperature were 6.0 and 60 degrees C, respectively. In the absence of substrate the purified alpha-amylase was stable for 1 h at 50 degrees C and had a half-life of 12 min at 60 degrees C, but was fully stable in the presence of starch. The enzyme was not activated by several metal ions tested, including Ca(2+) (up to 10 mM), but HgCl2 and CuCl2 inhibited its activity. The alpha-amylase produced by S. thermophilum preferentially hydrolyzed starch, and to a lesser extent amylopectin, maltose, amylose and glycogen in that order. The products of starch hydrolysis (up to 6 h of reaction) analyzed by thin layer chromatography, showed oligosaccharides such as maltotrioses, maltotetraoses and maltopentaoses. Maltose and traces of glucose were formed only after 3 h of reaction. These results confirm the character of the enzyme studied to be an alpha-amylase (1,4-alpha-glucan glucanohydrolase).