Fed-batch synthesis of galacto-oligosaccharides with Aspergillus oryzae β-galactosidase using optimal control strategy

Carlos Vera, Cecilia Guerrero, Andrés Illanes, Raúl Conejeros

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

Fed-batch synthesis of galacto-oligosaccharides (GOS) from lactose with β-galactosidase from Aspergillus oryzae was evaluated experimentally and reaction yield was maximized via optimal control technique. The optimal lactose and enzyme feed flow rate profiles were determined using a model for GOS synthesis previously reported by the authors. Experimentally it was found that fed-batch synthesis allowed an increase on the maximum total GOS concentration from 115 (batch synthesis) to 218 g L-1 as consequence of the increase in total sugars concentration from 40 to 58% w/w. Such high concentration of total sugars was not attainable in batch operation because of the low solubility of lactose at the reaction temperature (40°C). Simulations predicted a GOS yield of 32.5 g g-1 in fed-batch synthesis under optimal conditions, while experimentally the same yield as in batch synthesis was obtained (28 g g-1). Besides, an enrichment of total oligosaccharides in GOS with a high polymerization degree (GOS-5 and GOS-6) was observed in the fed-batch synthesis. Experimental profiles for all sugars were similar to the ones predicted by simulation, which supports the use of this methodology for the optimization of GOS synthesis.

Original languageEnglish
Pages (from-to)59-67
Number of pages9
JournalBiotechnology Progress
Volume30
Issue number1
DOIs
StatePublished - Jan 2014
Externally publishedYes

Keywords

  • Aspergillus oryzae
  • Fed-batch enzymatic synthesis
  • GOS
  • Galacto-oligosaccharides
  • Prebiotics
  • β-galactosidase

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