Title |
Development of a strategy for the screening of α-glucosidase-producing microorganisms |
Author |
Bo Zhou+, Nan Huang+, Wei Zeng+, Hao Zhang, Guiguang Chen, and Zhiqun Liang* |
Address |
State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Microorganism and Enzyme Research Center of Engineering Technology, College of Life Science and Technology, Guangxi University, 100 Daxue Road, Nanning 530004, Guangxi, P. R. China |
Bibliography |
Journal of Microbiology, 58(2),163-172, 2020,
|
DOI |
10.1007/s12275-020-9267-4
|
Key Words |
α-D-methylglucoside, α-glucosidase, eosin y, hydrolysis,
transglycosylation, Aspergillus niger |
Abstract |
α-Glucosidase is a crucial enzyme for the production of isomaltooligosaccharide.
In this study, a novel method comprising
eosin Y (EY) and α-D-methylglucoside (AMG) in glass
plates was tested for the primary screening of α-glucosidaseproducing
strains. First, α-glucosidase-producing Aspergillus
niger strains were selected on plates containing EY and AMG
based on transparent zone formation resulting from the solubilization
of EY by the hydrolyzed product. Conventional
methods that use trypan blue (TB) and p-nitrophenyl-α-Dglucopyranoside
(pPNP) as indicators were then compared
with the new strategy. The results showed that EY-containing
plates provide the advantages of low price and higher specificity
for the screening of α-glucosidase-producing strains.
We then evaluated the correlation between the hydrolytic activity
of α-glucosidase and diffusion distance, and found that
good linearity could be established within a 6–75 U/ml enzyme
concentration range. Finally, the hydrolytic and transglycosylation
activities of α-glucosidase obtained from the
target isolates were determined by EY plate assay and 3,5-
dinitrosalicylic acid-Saccharomyces cerevisiae assay, respectively.
The results showed that the diameter of the transparent
zone varied among isolates was positively correlated with
α-glucosidase hydrolytic activity, while good linearity could
also be established between α-glucosidase transglycosylation
activity and non-fermentable reducing sugars content. With
this strategy, 7 Aspergillus niger mutants with high yield of
α-glucosidase from 200 obvious single colonies on the primary
screen plate were obtained. |