A comparative study on galactoologosaccharide synthesis by selected beta-galactosidase preparations

The transgalactosilating ability of beta-galactosidase preparations obtained from Kluyveromyces fragilis, Penicillium canescens, and Escherichia coli was investigated. In samples of hydrolysates of 20% lactose solutions without or with a 2% addition of glucose, the galactose or fructose obtained with the use of the investigated preparations and the content of saccharides was determined with the HPLC method. Under experimental conditions, the highest quantity (56.0-64.1%) of galactooligosaccharides was synthesised by beta-galactosidase obtained from E. coli, while the lowest number (11.25-25.2%) was obtained by beta-galactosidase obtained from P. canescens. Beta-galactosidase from E. coli also synthesised considerable amounts of lactulose.