Immobilization of Bacillus circulans β-galactosidase and its application in the synthesis of galacto-oligosaccharides under repeated-batch operation

P. Urrutia, C. Mateo, J. M. Guisan, LORENA EVELYN WILSON SOTO, A. Illanes

Research output: Contribution to journalArticlepeer-review

52 Scopus citations

Abstract

A highly active and stable derivate of immobilized Bacillus circulans β-galactosidase was prepared for the synthesis of galacto-oligosaccharides (GOS) under repeated-batch operation. B. circulans β-galactosidase was immobilized on monofunctional glyoxyl agarose and three heterofunctional supports: amino-, carboxy-, and chelate-glyoxyl agarose. Glyoxyl agarose was the support with highest immobilization yield and stability being selected for the optimization of immobilization conditions and application in GOS synthesis. A central composite rotatable design was conducted to optimize contacted protein and immobilization time, using maximum catalytic potential as the objective function. Optimal conditions of immobilization were 28.9. mg/g and 36.4. h of contact, resulting in a biocatalyst with 595. IU/g and a half-life 89-fold higher than soluble enzyme. Immobilization process did not alter the synthetic capacity of β-galactosidase, obtaining the same GOS yield and product profile than the free enzyme. GOS yield and productivity remained unchanged along 10 repeated batches, with values of 39% (w/w) and 5.7. g GOS/g of biocatalyst·batch. Total product obtained after 10 batches of reaction was 56.5. g GOS/g of biocatalyst (1956. g GOS/g protein). Cumulative productivity in terms of mass of contacted protein was higher for the immobilized enzyme than for its soluble counterpart from the second batch of synthesis onwards.

Original languageEnglish
Pages (from-to)41-48
Number of pages8
JournalBiochemical Engineering Journal
Volume77
DOIs
StatePublished - 2013
Externally publishedYes

Keywords

  • β-Galactosidase
  • Agarose
  • Galacto-oligosaccharides
  • Immobilization
  • Optimization
  • Repeated-batch

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