Molecular cloning and biochemical characterization of an α-amylase family from Aspergillus niger
Electron. j. biotechnol
;
32: 55-62, Mar. 2018. tab, ilus, graf
Artículo
en Inglés
| LILACS
| ID: biblio-1022638
ABSTRACT
Background: α-Amylase is widely used in the starch processing, food and paper industries, hydrolyzing starch, glycogen and other polysaccharides into glucose, maltose and oligosaccharides. An α-amylase gene family from Aspergillus niger CBS513.88 encode eight putative α-amylases. The differences and similarities, biochemical properties and functional diversity among these eight α-amylases remain unknown. Results: The eight genes were cloned and expressed in Pichia pastoris GS115 by shaking-flask fermentation under the induction of methanol. The sequence alignment, biochemical characterizations and product analysis of starch hydrolysis by these α-amylases were investigated. It is found that the eight α-amylases belonged to three different groups with the typical structure of fungal α-amylase. They exhibited maximal activities at 3040°C except AmyG and were all stable at acidic pH. Ca2+ and EDTA had no effects on the activities of α-amylases except AmyF and AmyH, indicating that the six amylases were Ca2+ independent. Two novel α-amylases of AmyE and AmyF were found. AmyE hydrolyzed starch into maltose, maltotriose and a small amount of glucose, while AmyF hydrolyzed starch into mainly glucose. The excellent physical and chemical properties including high acidic stability, Ca2+-independent and high maltotriose-forming capacity make AmyE suitable in food and sugar syrup industries. Conclusions: This study illustrates that a gene family can encode multiple enzymes members having remarkable differences in biochemical properties. It provides not only new insights into evolution and functional divergence among different members of an α-amylase family, but the development of new enzymes for industrial application.
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LILACS (Américas)
Asunto principal:
Aspergillus niger
/
Alfa-Amilasas
Idioma:
Inglés
Revista:
Electron. j. biotechnol
Asunto de la revista:
Biotecnologia
Año:
2018
Tipo del documento:
Artículo
/
Documento de proyecto
País de afiliación:
China
Institución/País de afiliación:
Tianjin University of Science &Technology/CN
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