The GlaA signal peptide substantially increases the expression and secretion of α-galactosidase in Aspergillus niger
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α-Galactosidases are widely used in many fields. It is necessary to improve the production of enzymes through microbiological processes. The aim of this study was to construct recombinant Aspergillus niger strains with high α-galactosidase production.
Two recombinant A. niger strains were constructed: AB and AGB. The recombinant AB strain contained the α-galactosidase aglB gene from A. niger with its native AglB signal peptide regulated by the glucoamylase promoter. In the AGB recombinant strain, the AglB signal peptide was replaced with the glucoamylase (GlaA) signal peptide. The extracellular maximum α-galactosidase activity of the AGB strain was 215.7 U/ml and that of the AB strain was 9.8 U/mL. The optimal conditions for α-galactosidase were pH 3.5 and 35 °C.
The GlaA signal peptide substantially increased the yield of secreted α-galactosidase in A. niger. This recombinant strain holds great potential for industrial applications.
KeywordsAspergillus niger α-galactosidase Secretion Signal peptide
This work was supported by the Special Scientific Research Fund of Grain Public Welfare Profession of China (Project No. 201513006), and the Major Program of Application Technology Research and Development Program of Heilongjiang Province of China (Grant No. GA15B203).
Supplementary Table 1—List of primers used in this study.
Supplementary Fig. 1—Product of PCR amplification of aglB gene and aglB2 gene fragment from Aspergillus niger CICC2462.
Supplementary Fig. 2—Analysis of transformants of Aspergillus niger by agarose gel electrophoresis using PCR products digested by the restriction enzyme HindIII.
Supplementary Fig. 3—Predicted N-glycosylation sites in AglB.
Supplementary Fig. 4—Minimum free energy plain structure drawing of the mRNAs encoding.
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