Enhanced β-Galactosidase Production from Whey Powder by a Mutant of the Psychrotolerant Yeast Guehomyces pullulans 17-1 for Hydrolysis of Lactose.
Summary of "Enhanced β-Galactosidase Production from Whey Powder by a Mutant of the Psychrotolerant Yeast Guehomyces pullulans 17-1 for Hydrolysis of Lactose."
In order to isolate β-galactosidase overproducers of the psychrotolerant yeast Guehomyces pullulans 17-1, its cells were mutated by using nitrosoguanidine (NTG). One mutant (NTG-133) with enhanced β-galactosidase production was obtained. The mutant grown in the production medium with 30.0 g/l lactose and 2.0 g/l glucose could produce more β-galactosidase than the same mutant grown in the production medium with only 30.0 g/l lactose while β-galactosidase production by its wild type was sensitive to the presence of glucose in the medium. It was found that 40.0 g/l of the whey powder was the most suitable for β-galactosidase production by the mutant. After optimization of the medium and cultivation conditions, the mutant could produce 29.2 U/ml of total β-galactosidase activity within 132 h at the flask level while the mutant could produce 48.1 U/ml of total β-galactosidase activity within 144 h in 2-l fermentor. Over 77.1% of lactose in the whey powder (5.0% w/v) was hydrolyzed in the presence of the β-galactosidase activity of 280 U/g of lactose within 9 h while over 77.0% of lactose in the whey was hydrolyzed in the presence of β-galactosidase activity of 280 U/g of lactose within 6 h. This was the first time to show that the β-galactosidase produced by the psychrotolerant yeast could be used for hydrolysis of lactose in the whey powder and whey.
Affiliation
UNESCO Chinese Center of Marine Biotechnology and Institute of Marine Biodiversity and Evolution , Ocean University of China, Yushan Road, No. 5, Qingdao, 266003, China.
Journal Details
This article was published in the following journal.
Name: Applied biochemistry and biotechnology
ISSN: 1559-0291
Pages:
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22086565
- DOI: http://dx.doi.org/10.1007/s12010-011-9451-4
Medical and Biotech [MESH] Definitions
Beta-galactosidase
A group of enzymes that catalyzes the hydrolysis of terminal, non-reducing beta-D-galactose residues in beta-galactosides. Deficiency of beta-Galactosidase A1 may cause GANGLIOSIDOSIS, GM1.
Dry Powder Inhalers
A device that delivers medication to the lungs in the form of a dry powder.
Genetic Complementation Test
A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.
Mice, Mutant Strains
Mice bearing mutant genes which are phenotypically expressed in the animals.
Rats, Mutant Strains
Rats bearing mutant genes which are phenotypically expressed in the animals.
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