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Overexpression and characterization of a novel transgalactosylic and hydrolytic β-galactosidase from a human isolate Bifidobacterium breve B24

Paper ID Volume ID Publish Year Pages File Format Full-Text
33498 44980 2011 8 PDF Available
Title
Overexpression and characterization of a novel transgalactosylic and hydrolytic β-galactosidase from a human isolate Bifidobacterium breve B24
Abstract

After the complete gene of a β-galactosidase from human isolate Bifidobacterium breve B24 was isolated by PCR and overexpressed in E. coli, the recombinant β-galactosidase was purified to homogeneity and characterized for the glycoside transferase (GT) and glycoside hydrolase (GH) activities on lactose. One complete ORF encoding 691 amino acids (2076 bp) was the structural gene, LacA (galA) of the β-gal gene. The recombinant enzyme shown by activity staining and gel-filtration chromatography was composed of a homodimer of 75 kDa with a total molecular mass of 150 kDa. The Km value for lactose (95.58 mM) was 52.5-fold higher than the corresponding Km values for the synthetic substrate ONPG (1.82 mM). This enzyme with the optimum of pH 7.0 and 45°C could synthesize approximately 42.00% of GOS from 1 M of lactose. About 97.00% of lactose in milk was also quickly hydrolyzed by this enzyme (50 units) at 45°C for 5 h to produce 46.30% of glucose, 46.60% of galactose and 7.10% of GOS. The results suggest that this recombinant β-galactosidase derived from a human isolate B. breve B24 may be suitable for both the hydrolysis and synthesis of galacto-oligosaccharides (GOS) in milk and lactose processing.

► An over expressed β-gal gene of Bifidobacterium breve isolate is a Lac A (galA) of the β-gal gene. ► This enzyme active at neutral pH7.0 and 45 °C synthesized 42% of GOS from 1 M of lactose. ► This enzyme rapidly hydrolyzed 97.0% of lactose in milk. ► We examined a novel transgalactosylating and hydrolytic applications of Bifidobacterium breve β-gal.

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Overexpression and characterization of a novel transgalactosylic and hydrolytic β-galactosidase from a human isolate Bifidobacterium breve B24
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Publisher
Database: Elsevier - ScienceDirect
Journal: New Biotechnology - Volume 28, Issue 6, October 2011, Pages 806–813
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