Galacto-oligosaccharide production by a thermostable recombinant β-galactosidase from Thermotoga maritima

Article

DOI: 10.1007/s11274-004-5487-8

Cite this article as:
Ji, ES., Park, NH. & Oh, DK. World J Microbiol Biotechnol (2005) 21: 759. doi:10.1007/s11274-004-5487-8

Summary

A β-galactosidase from Thermotoga maritima produced galacto-oligosaccharides (GOS) from lactose by transgalactosylation when expressed in Escherichia coli. The enzyme activity for GOS production was maximal at pH 6.0 and 90 °C. In thermal stability experiments, the enzyme followed first-order kinetics of pH and thermal inactivation, and half-lives at pH 5.0, pH 8.0, 80 °C, and 95 °C were 27 h, 82 h, 41 h, and 14 min, respectively, suggesting that the enzyme was stable below 80 °C and in the pH range of 5.0–8.0. Mn2+ was the most effective divalent cation for GOS production. Cu2+ and EDTA inhibited more than 84% of enzyme activity. GOS production increased with increasing lactose concentrations and peaked at 500 g lactose/l. Among tested enzyme concentrations, the highest production of GOS was obtained at 1.5 units enzyme/ml. Under the optimal conditions of pH 6.0, 80 °C, 500 g lactose/l, and 1.5 units enzyme/ml, GOS production was 91 g/l for 300 min, with a GOS productivity of 18.2 g/l · h and a conversion yield of GOS to lactose of 18%.

Keywords

Galacto-oligosaccharide production thermostable recombinant β-galactosidase Thermotoga maritima 

Copyright information

© Springer 2005

Authors and Affiliations

  1. 1.Department of Bioscience and BiotechnologySejong UniversitySeoulKorea

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