Microbial and algal alginate gelation characterized by magnetic resonance

► Magnetic resonance techniques are used to quantify differences in the physical gelation of alginate from microbes and algae. ► Differences in water diffusion, T1, and T2 magnetic relaxation times are monitored as the gel forms and ages. ► O-Deacetylated alginate from Pseudomonas aeruginosa FRD1153...

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Veröffentlicht in:Journal of biotechnology 2012-10, Vol.161 (3), p.320-327
Hauptverfasser: Fabich, Hilary T., Vogt, Sarah J., Sherick, Matthew L., Seymour, Joseph D., Brown, Jennifer R., Franklin, Michael J., Codd, Sarah L.
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Sprache:eng
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Zusammenfassung:► Magnetic resonance techniques are used to quantify differences in the physical gelation of alginate from microbes and algae. ► Differences in water diffusion, T1, and T2 magnetic relaxation times are monitored as the gel forms and ages. ► O-Deacetylated alginate from Pseudomonas aeruginosa FRD1153 forms the most rigid and heterogeneous gel. ► Bacterial alginates form a more rigid and heterogeneous gel than algal alginate. ► Bacterial alginates contract and expel water more than algal alginate indicating larger molecular stress during gelation. Advanced magnetic resonance (MR) relaxation and diffusion correlation measurements and imaging provide a means to non-invasively monitor gelation for biotechnology applications. In this study, MR is used to characterize physical gelation of three alginates with distinct chemical structures; an algal alginate, which is not O-acetylated but contains poly guluronate (G) blocks, bacterial alginate from Pseudomonas aeruginosa, which does not have poly-G blocks, but is O-acetylated at the C2 and/or C3 of the mannuronate residues, and alginate from a P. aeruginosa mutant that lacks O-acetyl groups. The MR data indicate that diffusion-reaction front gelation with Ca2+ ions generates gels of different bulk homogeneities dependent on the alginate structure. Shorter spin–spin T2 magnetic relaxation times in the alginate gels that lack O-acetyl groups indicate stronger molecular interaction between the water and biopolymer. The data characterize gel differences over a hierarchy of scales from molecular to system size.
ISSN:0168-1656
1873-4863
DOI:10.1016/j.jbiotec.2012.04.016