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Exploiting Mannuronan C-5 Epimerases in Commercial Alginate Production

Authors :
Anne Tøndervik
Olav A. Aarstad
Randi Aune
Susan Maleki
Philip D. Rye
Arne Dessen
Gudmund Skjåk-Bræk
Håvard Sletta
Source :
Marine Drugs, Vol 18, Iss 11, p 565 (2020)
Publication Year :
2020
Publisher :
MDPI AG, 2020.

Abstract

Alginates are one of the major polysaccharide constituents of marine brown algae in commercial manufacturing. However, the content and composition of alginates differ according to the distinct parts of these macroalgae and have a direct impact on the concentration of guluronate and subsequent commercial value of the final product. The Azotobacter vinelandii mannuronan C-5 epimerases AlgE1 and AlgE4 were used to determine their potential value in tailoring the production of high guluronate low-molecular-weight alginates from two sources of high mannuronic acid alginates, the naturally occurring harvested brown algae (Ascophyllum nodosum, Durvillea potatorum, Laminaria hyperborea and Lessonia nigrescens) and a pure mannuronic acid alginate derived from fermented production of the mutant strain of Pseudomonas fluorescens NCIMB 10,525. The mannuronan C-5 epimerases used in this study increased the content of guluronate from 32% up to 81% in both the harvested seaweed and bacterial fermented alginate sources. The guluronate-rich alginate oligomers subsequently derived from these two different sources showed structural identity as determined by proton nuclear magnetic resonance (1H NMR), high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD) and size-exclusion chromatography with online multi-angle static laser light scattering (SEC-MALS). Functional identity was determined by minimum inhibitory concentration (MIC) assays with selected bacteria and antibiotics using the previously documented low-molecular-weight guluronate enriched alginate OligoG CF-5/20 as a comparator. The alginates produced using either source showed similar antibiotic potentiation effects to the drug candidate OligoG CF-5/20 currently in development as a mucolytic and anti-biofilm agent. These findings clearly illustrate the value of using epimerases to provide an alternative production route for novel low-molecular-weight alginates.

Details

Language :
English
ISSN :
16603397
Volume :
18
Issue :
11
Database :
Directory of Open Access Journals
Journal :
Marine Drugs
Publication Type :
Academic Journal
Accession number :
edsdoj.f1ebc2b6a49a4202a2c1ab15a21003e5
Document Type :
article
Full Text :
https://doi.org/10.3390/md18110565