Molecular cloning and biochemical characterization of an α-amylase family from Aspergillus niger
Electron. j. biotechnol
; Electron. j. biotechnol;32: 55-62, Mar. 2018. tab, ilus, graf
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| ID: biblio-1022638
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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.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
LILACS
Assunto principal:
Aspergillus niger
/
Alfa-Amilases
Idioma:
En
Revista:
Electron. j. biotechnol
Assunto da revista:
BIOTECNOLOGIA
Ano de publicação:
2018
Tipo de documento:
Article
/
Project document
País de afiliação:
China
País de publicação:
Chile