The use of crude cell extracts of lactic acid bacteria optimized for beta-galactosidase activity to form galactooligosaccharides with lactose, mannose, fucose, and N-acetylglucosamine

  • Author / Creator
    Lee, Vivian Shin Yuan
  • Several lactic acid bacteria contain β-galactosidases. Beta galactosidases catalyze lactose hydrolysis and transfer acceptor sugars onto galactose, producing galactooligosaccharides. The aim of this work was to exploit β-galactosidases of lactic acid bacteria as crude cell extracts to produce novel oligosaccharides with mannose, N-acetylglucosamine, and fucose. Of 17 strains of lactic acid bacteria, transferase activity was the strongest in crude cell extracts of Lactobacillus delbrueckii subsp. bulgaricus, followed by Streptococcus thermophilus, Lactobacillus animalis, and Lactobacillus reuteri in a buffered 19% (w/w) lactose solution. Incorporation of 6 % (w/w) glycerol increased transferase activity and enzyme stability at higher incubation temperatures. Incorporation of 10% (w/w) mannose, N-acetylglucosamine and fucose as acceptor sugars yielded three distinct oligosaccharides with mannose and two with N-acetylglucosamine and fucose, with the composition confirmed using gas chromatography-mass spectrometry. This is the first public report indicating production of oligosaccharides containing N-acetylglucosamine and fucose from β-galactosidases of lactic acid bacteria.

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  • Degree
    Master of Science
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