Effect of particle size and enzyme load on the simultaneous reactions of lactose hydrolysis and transgalactosylation with glyoxyl-agarose immobilized β-galactosidase from Aspergillus oryzae. (October 2018)

• Record Type: Journal Article
• Authors: Suárez, Sebastián; Guerrero, Cecilia; Vera, Carlos; Illanes, Andrés
• Is Part Of: Process biochemistry. Volume 73(2018)
• Page Start: 56
• Page End: 64
• Publication Date: 2018-10
• Subjects: β-Galactosidase -- Glyoxyl-agarose -- Lactose hydrolysis -- Lactose transgalactosylation -- Galacto-oligosaccharides -- Diffusional restrictions; Biochemical engineering -- Periodicals; Biotechnology -- Periodicals; Biochemistry -- periodicals; Biotechnology -- periodicals; Chemical Engineering -- periodicals; Génie biochimique -- Périodiques; Biotechnologie -- Périodiques; Biochemical engineering; Biotechnology; Periodicals; 660.63
• DOI: 10.1016/j.procbio.2018.08.016
• Languages: English
• ISSNs: 1359-5113

Abstract

Graphical abstract: Highlights: β-galactosidase was immobilized in glyoxyl agarose of different size and enzyme load. Galactose-glucose ratio increased with the increase in diffusional restrictions. Ratio of initial reaction rates allow determining the prevalence of each reaction. A small sized catalyst makes transgalactosylation prevail over hydrolysis. A low loaded catalyst makes transgalactosylation prevail over hydrolysis. Abstract: The simultaneous reactions of lactose hydrolysis and transgalactosylation in the production of galacto-oligosaccharides (GOS) were evaluated with immobilized Aspergillus oryzae β-galactosidase in glyoxyl-agarose of different particle sizes (fine and macro) and enzyme loads (1, 10 and 30 mgprotein /gsupport ) to produce biocatalysts subjected to different magnitudes of internal diffusional restrictions. The ratio of initial reaction rates depended on the initial concentration of lactose: at values higher than 800 mM, the ratio of hydrolysis to total reaction rate (rhydr /rtotal ), which reflects the hydrolytic potential, had values of 16 and 30%, and the ratio of transgalactosylation to total reaction rates (rtransgal /rtotal ), which reflects the transgalactosylation potential, had values of 84 and 70% with the biocatalysts of smaller size and enzyme load, and bigger size and enzyme load, respectively. Results obtained highlight the fact that the biocatalyst should be optimized with regard to its intended use; β-galactosidase biocatalysts that have been optimized for lactose hydrolysis can be quite inadequate for performing GOS synthesis.