Dendrimer-like nanoparticles based beta-galactosidase assembly for enhancing its selectivity toward transgalactosylation

Mailin Misson, and Du, Xin and Jin, Bo and Zhang, Hu (2016) Dendrimer-like nanoparticles based beta-galactosidase assembly for enhancing its selectivity toward transgalactosylation. Enzyme and Microbial Technology, 84. pp. 68-77. ISSN 0141-0229

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Functional nanomaterials have been pursued to assemble nanobiocatalysts since they can provide unique hierarchical nanostructures and localized nanoenvironments for enhancing enzyme specificity, stability and selectivity. Functionalized dendrimer-like hierarchically porous silica nanoparticles (HPSNs) was fabricated for assembling β-galactosidase nanobiocatalysts for bioconversion of lactose to galacto-oligosaccharides (GOS). The nanocarrier was functionalized with amino (NH2) and carboxyl (COOH) groups to facilitate enzyme binding, benchmarking with non-functionalized HPSNs. Successful conjugation of the functional groups was confirmed by FTIR, TGA and zeta potential analysis. HPSNs-NH2 showed 1.8-fold and 1.1-fold higher β-galactosidase adsorption than HPSNs-COOH and HPSNs carriers, respectively, with the highest enzyme adsorption capacity of 328 mg/g nanocarrier at an initial enzyme concentration of 8 mg/ml. The HPSNs-NH2 and β-galactosidase assembly (HPSNs-NH2-Gal) demonstrated to maintain the highest activity at all tested enzyme concentrations and exhibited activity up to 10 continuous cycles. Importantly, HPSNs-NH2-Gal was simply recycled through centrifugation, overcoming the challenging problems of separating the nanocarrier from the reaction medium. HPSNs-NH2-Gal had distinguished catalytic reaction profiles by favoring transgalactosylation, enhancing GOS production of up to 122 g/l in comparison with 56 g/l by free β-galactosidase. Furthermore, it generated up to 46 g/l GOS at a lower initial lactose concentration while the free counterpart had negligible GOS production as hydrolysis was overwhelmingly dominant in the reaction system. Our research findings show the amino-functionalized HPSNs can selectively promote the enzyme activity of β-galactosidase for transgalactosylation, which is beneficial for GOS production.

Item Type: Article
Keyword: Nanobiocatalysis, β-Galactosidase, Dendrimer-like hierarchical pores silica nanoparticles, Galacto-oligosaccharides
Subjects: Q Science > QR Microbiology
Department: INSTITUTE > Biotechnology Research Institute (BRI)
Depositing User: ADMIN ADMIN
Date Deposited: 03 Aug 2016 14:12
Last Modified: 03 Aug 2016 14:12

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