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Characterisation of a novel cellobiose 2-epimerase from thermophilic Caldicellulosiruptor obsidiansis for lactulose production.
- Source :
-
Journal of the science of food and agriculture [J Sci Food Agric] 2017 Aug; Vol. 97 (10), pp. 3095-3105. Date of Electronic Publication: 2016 Dec 30. - Publication Year :
- 2017
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Abstract
- Background: Lactulose, a bioactive lactose derivative, has been widely used in food and pharmaceutical industries. Isomerisation of lactose to lactulose by cellobiose 2-epimerase (CE) has recently attracted increasing attention, since CE produces lactulose with high yield from lactose as a single substrate. In this study, a new lactulose-producing CE from Caldicellulosiruptor obsidiansis was extensively characterised.<br />Results: The recombinant enzyme exhibited maximal activity at pH 7.5 and 70 °C. It displayed high thermostability with T <subscript>m</subscript> of 86.7 °C. The half-life was calculated to be 8.1, 2.8 and 0.6 h at 75, 80, and 85 °C, respectively. When lactose was used as substrate, epilactose was rapidly produced in a short period, and afterwards both epilactose and lactose were steadily isomerised to lactulose, with a final ratio of 35:11:54 for lactose:epilactose:lactulose. When the reverse reaction was investigated using lactulose as substrate, both lactose and epilactose appeared to be steadily produced from the start.<br />Conclusion: The recombinant CE showed both epimerisation and isomerisation activities against lactose, making it an alternative promising biocatalyst candidate for lactulose production. © 2016 Society of Chemical Industry.<br /> (© 2016 Society of Chemical Industry.)
- Subjects :
- Bacterial Proteins chemistry
Bacterial Proteins genetics
Cellobiose chemistry
Enzyme Stability
Firmicutes chemistry
Firmicutes genetics
Hot Temperature
Hydrogen-Ion Concentration
Kinetics
Lactose chemistry
Lactose metabolism
Lactulose chemistry
Racemases and Epimerases chemistry
Racemases and Epimerases genetics
Substrate Specificity
Bacterial Proteins metabolism
Cellobiose metabolism
Firmicutes enzymology
Lactulose metabolism
Racemases and Epimerases metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1097-0010
- Volume :
- 97
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- Journal of the science of food and agriculture
- Publication Type :
- Academic Journal
- Accession number :
- 27873314
- Full Text :
- https://doi.org/10.1002/jsfa.8148