Identification and characterization of novel transglycosylating α‐glucosidase from Aspergillus neoniger

Abstract

Aim Aspergillus niger is well established for secreting α‐glucosidase having transglycosylation activity, which is used as processing aid for synthesis of isomaltooligosaccharides. The present study focuses on identification and characterization of a non‐niger Aspergillus isolate and its gene conferring strong transglycosylation activity. Methods and Results The soil isolate was identified as Aspergillus neoniger belonging to Aspergillus section Nigri using ITS (internal transcribed spacer) and β‐tubulin analysis. The sequence analysis of gene responsible for α‐glucosidase synthesis revealed significant nucleotide variations when compared to other Aspergillus species. Molecular docking studies using the homology model revealed the presence of threonine at 694 subsite position instead of asparagine as in case of A. niger's α‐glucosidase. The enzyme was purified to several fold using DEAE Sepharose‐CL6B column and on SDS‐PAGE analysis, it was found to be 145 kDa. MS/MS analysis of the purified enzyme validated the presence of threonine at 694 position. Commercial α‐glucosidase (Transglucosidase L ‘Amano’) derived from A. niger and the α‐glucosidase from isolate were compared for transglycosylation activity using constant test conditions. α‐glucosidase from the isolate produced 27·4% higher panose when compared to that of commercial enzyme. Moreover, the rate of secondary hydrolysis of panose is much lower in case of the isolate's enzyme. Conclusions Fungal isolate A. neoniger was characterized, and its gene conferring α‐glucosidase activity was established for strong transglycosylation activity having higher panose yields. Significance and Impact of the Study To the best of our knowledge, this is the first report to establish a variant of α‐glucosidase having strong transglycosylation activity from A. neoniger strain. We have demonstrated that this enzyme when used as processing aid could improve panose significantly, which is a potential prebiotic. Also, the sequence analysis established in our studies could provide pointers for directed evolution of this enzyme to further improve transglycosylation activity.

Synergistic effects of multiple enzymes from industrial Aspergillus niger strain O1 on starch saccharification

“…Additionally, endoglucanase A is an enzyme belonging to GH12 with the annotation of cellulase activity. Although α-glucosidase is a starch-degrading glycoside hydrolase in fermentation cultures, it is undesirable for starch saccharification because of its transglycosylation activity for producing unfermentable sugars [ 32 – 34 ]. Other glycoside hydrolases detected in fermentation supernatants are related to the degradation of other polysaccharides not starch (Additional file 1 : Fig.…”

Production of a Series of Long-Chain Isomaltooligosaccharides from Maltose by Bacillus subtilis AP-1 and Associated Prebiotic Properties

“…Further, α-glucosidases are mainly derived from microorganisms, with only a few from plants and animals. Some microorganisms are reported to produce α-glucosidases with transglucosylation activity, including Aspergillus neoniger [ 15 ], Aspergillus niger [ 16 ], Bacillus licheniformis strain TH4-2 [ 17 ], Geobacillus stearothermophilus [ 18 ], Xanthophyllomyces dendrorhous [ 19 ] and Bacillus subtilis SS-76 [ 20 ].…”

Biochemical characterization of glycoside hydrolase family 31 α-glucosidases from Myceliophthora thermophila for α-glucooligosaccharide synthesis

“…GH31 α-glucosidases from Aspergillus sojae (AsojAgdL) [15], Aspergillus neoniger (AG) [16,17], Xantophyllomyces dendrorhous [18], and Aspergillus oryzae ZL-1 (AgdA) [19] have also been reported to catalyze the synthesis of α-(1→6) linked glucooligosaccharides. Besides, GH31 α-glucosidases from Acremonium implicatum (AiG) [20], Paecilomyces lilacinus [21] and A. niger (AgdB) [9,22] α-glucooligosaccharides are reported to exhibit prebiotic effects [23][24][25][26].…”