Removal of flatulence-inducing sugars by using free and polyvinyl alcohol immobilized α-Galactosidase from Aspergillus oryzae

A new α-galactosidase from thermoacidophilic Alicyclobacillus sp. A4 with wide acceptor specificity for transglycosylation

An α-galactosidase gene (gal36A4) of glycosyl hydrolase family 36 was identified in the genome of Alicyclobacillus sp. A4. It contains an ORF of 2,187 bp and encodes a polypeptide of 728 amino acids with a calculated molecular mass of 82.6 kDa. Deduced Gal36A4 shows the typical GH36 organization of three domains--the N-terminal β-sheets, the catalytic (β/α)8-barrels, and the C-terminal antiparallel β-sheet. The gene product was produced in Escherichia coli and showed both hydrolysis and transglycosylation activities. The optimal pH for hydrolysis activity was 6.0, and a stable pH range of 5.0-11.0 was found. The enzyme had a temperature optimum of 60 °C. It is specific for α-1,6-glycosidic linkages and had a K m value of 1.45 mM toward pNPGal. When using melibiose as both donor and acceptor of galactose, Gal36A4 showed the transfer ratio of 23.25 % at 96 h. With respect to acceptor specificity, all tested monosaccharides, disaccharides, and oligosaccharides except for D-xylose and L-arabinose were good acceptors for transglycosylation. Thus, Gal36A4 may find diverse applications in industrial fields, especially in the food industry.

Solid-State Fermentation Production of α-Galactosidase by Aspergillus niger Zju-Y1

The agro-byproduct culture medium for α-galactosidase production by Aspergillus niger zju-Y1 was optimized with flask-SSF via response surface methodology, maximum α-galactosidase yield at the level of 230.159 U/g dry matter was achieved by using wheat bran and soybean meal as culture medium components. Furthermore, based on the flask-SSF results, the three-section-control strategy was developed for scale-up SSF, making fermentation steadily and efficiently, and the α-galactosidase activity hitting to 174.410 U/g dry matter, which is close to the result of flask-SSF. The results demonstrated that a feasible scale-up SSF mode for α-galactosidase production is successfully set up by combining the utilization of agro-byproduct culture medium and three-section-control strategy.