Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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Record number 438194
Title Characterization of ß-Galactosidase Isoforms from Bacillus circulans and Their Contribution to GOS Production
Author(s) Warmerdam, A.; Paudel, E.; Wanqing, J.; Boom, R.M.; Janssen, A.E.M.
Source Applied Biochemistry and Biotechnology 170 (2013)2. - ISSN 0273-2289 - p. 340 - 358.
DOI https://doi.org/10.1007/s12010-013-0181-7
Department(s) Food Process Engineering
Onderwijsinstituut
VLAG
Publication type Refereed Article in a scientific journal
Publication year 2013
Keyword(s) lactose
Abstract A ß-galactosidase preparation from Bacillus circulans consists of four isoforms called ß-gal-A, ß-gal-B, ß-gal-C, and ß-gal-D. These isoforms differ in lactose hydrolysis and galacto-oligosaccharide (GOS) synthesis at low substrate concentrations. For this reason, using a selection of the isoforms may be relevant for GOS production, which is typically done at high substrate concentrations. At initial lactose concentrations in between 0.44% and 0.68% (w/w), ß-gal-A showed the least oligosaccharide formation, followed by ß-gal-B and ß-gal-C; most oligosaccharides were formed by ß-gal-D. The differences in behavior were confirmed by studying the thermodynamics of lactose conversion with isothermal titration calorimetry since especially ß-gal-A showed a different profile than the other isoforms. Also during the conversion of allolactose and 4-galactosyllactose at 0.44 % and 0.61 % (w/w), respectively, ß-gal-A and ß-gal-D showed clear differences. In contrast to above findings, the selectivity of the isoforms did hardly differ at an initial lactose concentration of 30 % (w/w), except for a slightly higher production of galactose with ß-gal-A. These differences were hypothesized to be related to the different accessibility of the active sites of the isoforms for different-sized reactants. The initial GOS formation rates of the isoforms indicate that ß-gal-A and ß-gal-B are the best isoforms for GOS production at high lactose concentrations
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