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Process development for the production of prebiotic galacto‐oligosaccharides from lactose using β‐galactosidase from Lactobacillus sp.
Author(s) -
Splechtna Barbara,
Nguyen ThuHa,
Zehetner Romana,
Lettner Hans Peter,
Lorenz Werner,
Haltrich Dietmar
Publication year - 2007
Publication title -
biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.144
H-Index - 84
eISSN - 1860-7314
pISSN - 1860-6768
DOI - 10.1002/biot.200600230
Subject(s) - lactose , chemistry , yield (engineering) , substrate (aquarium) , prebiotic , beta galactosidase , enzyme , sugar , trisaccharide , chromatography , food science , biochemistry , escherichia coli , materials science , biology , ecology , metallurgy , gene
Galacto‐oligosaccharides (GOS) are formed from lactose in discontinuous mode of conversion using β‐galactosidase from Lactobacillus sp. (β‐gal). The discontinuous process was optimized for technical application with regard to GOS yield, enzyme preparation, reaction temperature and substrate source. It proved to be advantageous to directly apply the crude cell‐free enzyme extract for the conversion, since similar GOS yields and composition were obtained as when using the pure enzyme preparation, but expensive purification could be avoided. Reaction temperature was lowered to 17°C to limit microbial contamination when using technical substrates. Thereby GOS yield decreased from 30% to 28% of total sugars and enzyme demand increased 2.7‐fold. Whey permeate was compared to buffered lactose solution as a substrate source. The initial reaction rate was found to be 1.8 times higher for the whey permeate substrate; however, GOS yield was slightly lower (approximately 25% of total sugar at 17°C) mainly due to smaller amounts of allolactose[β‐ D ‐Gal p ‐(1→6)‐ D ‐Glc] and the trisaccharide β‐ D ‐Gal p ‐(1→6)‐ D ‐Lac formed.