Facile Pretreatment of Bacillus circulans β-Galactosidase Increases the Yield of Galactosyl Oligosaccharides in Milk and Lactose Reaction Systems

The commercially available preparation of β-galactosidase from Bacillus circulans, known as Biolacta FN5, has been extensively used in the production of prebiotic galactooligosaccharides (GOS). This study focuses on characterizing the production of GOS in two reaction systems: 10% lactose (w/v) in buffer and skim milk. Analysis of the temperature dependence of the GOS yield along with the relative rates of GOS synthesis and degradation leads to the finding that GOS degradation activity was selectively decreased in Biolacta FN5 above 40 C. Facile heat treatment of Biolacta FN5 solution prior to use allowed for GOS yields to be significantly increased in both reaction systems.