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Thermostable β-galactosidases for the synthesis of human milk oligosaccharides

Paper ID Volume ID Publish Year Pages File Format Full-Text
32923 44951 2016 6 PDF Available
Title
Thermostable β-galactosidases for the synthesis of human milk oligosaccharides
Abstract

•Two thermostable GH1 β-galactosidases catalyzed formation of LacNAc from GlcNAc and lactose.•Two thermostableGH1 β-galactosidases catalyzed formation of LNnT from LNT2 and lactose.•Highest yields of LacNAc and LNnT were obtained with a GH42 β-galactosidase from B. circulans.•LacNAc formation was markedly improved by a temperature increase from 40°C to 50°C.

Human milk oligosaccharides (HMOs) designate a unique family of bioactive lactose-based molecules present in human breast milk. Using lactose as a cheap donor, some β-galactosidases (EC 3.2.1.23) can catalyze transgalactosylation to form the human milk oligosaccharide lacto-N-neotetraose (LNnT; Gal-β(1,4)-GlcNAc-β(1,3)-Gal-β(1,4)-Glc). In order to reduce reaction times and be able to work at temperatures, which are less welcoming to microbial growth, the current study investigates the possibility of using thermostable β-galactosidases for synthesis of LNnT and N-acetyllactosamine (LacNAc; Gal-β(1,4)-GlcNAc), the latter being a core structure in HMOs. Two hyperthermostable GH 1 β-galactosidases, Ttβ-gly from Thermus thermophilus HB27 and CelB from Pyrococcus furiosus, were codon-optimized for expression in Escherichia coli along with BgaD-D, a truncated version of the GH 42 β-galactosidase from Bacillus circulans showing high transgalactosylation activity at low substrate concentrations. The three β-galactosidases were compared in the current study in terms of their transgalactosylation activity in the formation of LacNAc and LNnT. In all cases, BgaD-D was the most potent transgalactosidase, but both thermostable GH 1 β-galactosidases could catalyze formation of LNnT and LacNAc, with Ttβ-gly giving higher yields than CelB. The thermal stability of the three β-galactosidases was elucidated and the results were used to optimize the reaction efficiency in the formation of LacNAc, resulting in 5–6 times higher reaction yields and significantly shorter reaction times.

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Thermostable β-galactosidases for the synthesis of human milk oligosaccharides
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Publisher
Database: Elsevier - ScienceDirect
Journal: New Biotechnology - Volume 33, Issue 3, 25 May 2016, Pages 355–360
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us