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β-Galactosidase over-production by a mig1 mutant of Kluyveromyces marxianus KM for efficient hydrolysis of lactose

Paper ID Volume ID Publish Year Pages File Format Full-Text
3379 167 2013 8 PDF Available
Title
β-Galactosidase over-production by a mig1 mutant of Kluyveromyces marxianus KM for efficient hydrolysis of lactose
Abstract

•The MIG1 gene in Kluyveromyces marxianus KM was disrupted.•β-Galactosidase activity of 121.0 U/ml was produced by the disruptant KM-15.•Lactose was actively hydrolyzed.•The end products of the lactose hydrolysis were only glucose and galactose.

In this study, the MIG1 gene in the industrial yeast Kluyveromyces marxianus KM was disrupted by integrating the HPT gene (encoding hygromycin B phosphotransferase) into ORF (Open Reading Frame) of the MIG1 gene. The disruptant (mig1 mutant) KM-15 obtained could grow in the media containing hygromycin or 2-deoxy-d-glucose, respectively. β-Galactosidase production and expression of its gene in the disruptant KM-15 were significantly enhanced compared to those in K. marxianus KM. This confirmed that Mig1, the transcriptional repressor, indeed regulated expression of the gene and biosynthesis of the enzyme in K. marxianus KM. Under the optimal conditions, the β-galactosidase activity of 121.0 U/mL was produced by the disruptant KM-15 within 60 h during 2-L fermentation. 99.2% of lactose in 9.0% of lactose solution, 99.0% of lactose in 12.0% of whey powder suspension and 99.3% of lactose in the milk were hydrolyzed by the crude β-galactosidase within 3 h, 4 h and 3 h, respectively. The end products of the lactose hydrolysis were only glucose and galactose.

Keywords
MIG1 gene; Kluyveromyces marxianus; β-Galactosidase; Biocatalysis; Metabolic engineering; Biomass
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β-Galactosidase over-production by a mig1 mutant of Kluyveromyces marxianus KM for efficient hydrolysis of lactose
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biochemical Engineering Journal - Volume 76, 15 July 2013, Pages 17–24
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