A high-throughput method for screening of Aspergillus niger mutants with high transglycosylation activity by detecting non-fermentable reducing sugar

• Published in: World journal of microbiology & biotechnology Vol. 27; no. 6; pp. 1519 - 1523
• Main Authors: Chen, Gui-guang, Li, Wei, Zhang, Yun-kai, Qin, Yong-ling, Wu, Kong-yang, Liang, Zhi-qun
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.06.2011; Springer; Springer Nature B.V
• Subjects: Analysis; Applied Microbiology; Biochemistry; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Cassava; Environmental Engineering/Biotechnology; Enzymes; Fermentation; Fundamental and applied biological sciences. Psychology; Fungi; Glucose; Laboratories; Life Sciences; Microbiology; Mutants; Mutation; Short Communication; Studies; Sugar; Yeast; Yeasts; Isomaltooligosaccharides; Transglucosidase; High-throughput method; Fungi; Transglycosylation; Screening; Aspergillus niger; Fungi Imperfecti; Mutation; Method; Sugar
• ISSN: 0959-3993; 1573-0972
• DOI: 10.1007/s11274-010-0595-0

A novel high-throughput method was established for rapid screening of large numbers of Aspergillus niger mutants with high transglucosylation activity by exploiting that yeast can hardly hydrolyze isomaltooligosaccharides (IMO). Supernatants of A . niger fermentation were incubated with Saccharomyces cerevisiae to remove glucose and maltose, and the remaining non-reducing sugars, which is positively correlated with the amount of IMO, the products of transglucosylation reaction, were used as indicator of transglucosidase activity of A . niger and examined by dinitrosalicylic acid assay. Using this method, 15 stains that could convert liquefied cassava starch to IMO more efficiently were selected from 8721 A . niger mutants. Among them, mutant C-6181 strain had transglycosidase activity of 4.61 U/ml (increased by 122% compared to its parental strain) and IMO yield of 83.7%. Taking together, the method is easy, simple, efficient and cheap, and has great application potential in selection of transglucosidase-producing strains used in industrial IMO fermentation.