Galacto-oligosaccharides Synthesis from Lactose and Whey by β-Galactosidase Immobilized in PVA

Autor: Eleonora Winkelhausen, Ruzica Jovanovic-Malinovska, Luís P. Fonseca, Pedro Fernandes
Rok vydání: 2012
Předmět:
Zdroj: Applied Biochemistry and Biotechnology. 168:1197-1211
ISSN: 1559-0291
0273-2289
DOI: 10.1007/s12010-012-9850-1
Popis: The synthesis of galacto-oligosaccharides (GOS) by β-galactosidase immobilized in both polyvinyl alcohol (PVA) lenses and sol-gel carriers was studied and compared with the performance of the free enzyme. PVA-immobilized β-galactosidase retained 95 % of the initial activity after seven repeated uses and retained 51 % of the initial activity after 3 months of storage, while sol-gel-immobilized β-galactosidase only retained 39 % of the initial activity under storage. Lactose conversion takes place at a higher rate in the PVA-immobilized β-galactosidase, while the lowest rate of lactose conversion was noticed with immobilized β-galactosidase in sol-gel. Continuous production of GOS from either lactose or whey, with PVA-immobilized β-galactosidase, was performed in a packed-bed reactor. A maximum GOS production of 30 % of total sugars was attained for a 40-% lactose feed solution with a feed rate of 10.8 ml/h, at pH 4.5 and 40 °C, corresponding to a productivity of 117 g/l h. The maximum GOS productivity of 344 g/l h was obtained at a flow rate of 28.7 ml/h. 3-OS and 4-OS were the major types of GOS formed. Conversion of whey in continuous mode resulted in GOS production of 15 % of total sugars and formation of 45 % 3-OS, 40 % 4-OS, and 15 % 5-OS.
Databáze: OpenAIRE
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