September 22, 2019  |  

Alpha- and beta-mannan utilization by marine Bacteroidetes.

Authors: Chen, Jing and Robb, Craig S and Unfried, Frank and Kappelmann, Lennart and Markert, Stephanie and Song, Tao and Harder, Jens and Avci, Burak and Becher, Dörte and Xie, Ping and Amann, Rudolf I and Hehemann, Jan-Hendrik and Schweder, Thomas and Teeling, Hanno

Marine microscopic algae carry out about half of the global carbon dioxide fixation into organic matter. They provide organic substrates for marine microbes such as members of the Bacteroidetes that degrade algal polysaccharides using carbohydrate-active enzymes (CAZymes). In Bacteroidetes genomes CAZyme encoding genes are mostly grouped in distinct regions termed polysaccharide utilization loci (PULs). While some studies have shown involvement of PULs in the degradation of algal polysaccharides, the specific substrates are for the most part still unknown. We investigated four marine Bacteroidetes isolated from the southern North Sea that harbour putative mannan-specific PULs. These PULs are similarly organized as PULs in human gut Bacteroides that digest a- and ß-mannans from yeasts and plants respectively. Using proteomics and defined growth experiments with polysaccharides as sole carbon sources we could show that the investigated marine Bacteroidetes express the predicted functional proteins required for a- and ß-mannan degradation. Our data suggest that algal mannans play an as yet unknown important role in the marine carbon cycle, and that biochemical principles established for gut or terrestrial microbes also apply to marine bacteria, even though their PULs are evolutionarily distant.© 2018 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

Journal: Environmental microbiology
DOI: 10.1111/1462-2920.14414
Year: 2018

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