Macroalgal surface constitutes a peculiar ecological niche and an advantageous substratum for microorganisms able to degrade the wide diversity of algal glycans. The degrading enzymatic activities of macroalgal epiphytes are of paramount interest for the industrial by-product sector and biomass resource applications. We characterized the polysaccharide hydrolytic profile of bacterial isolates obtained from three macroalgal species: the red macroalgae Asparagopsis taxiformis and Sphaerococcus coronopifolius (Rhodophyceae) and the brown Halopteris scoparia (Phaeophyceae), sampled in South Portugal. Bacterial enrichment cultures supplemented with chlorinated aliphatic compounds, typically released by marine algae, were established using as inoculum the decaying biomass of the three macroalgae, obtaining a collection of 634 bacterial strains. Although collected from the same site and exposed to the same seawater seeding microbiota, macroalgal cultivable bacterial communities in terms of functional and phylogenetic diversity showed host specificity. Isolates were tested for the hydrolysis of starch, pectin, alginate and agar, exhibiting a different hydrolytic potential according to their host: A. taxiformis showed the highest percentage of active isolates (91%), followed by S. coronopifolius (54%) and H. scoparia (46%). Only 30% of the isolates were able to degrade starch, while the other polymers were degraded by 55-58% of the isolates. Interestingly, several isolates showed promiscuous capacities to hydrolyze more than one polysaccharide. The isolate functional fingerprint was statistically correlated to bacterial phylogeny, host species and enrichment medium. In conclusion, this work depicts macroalgae as holobionts with an associated microbiota of interest for blue biotechnologies, suggesting isolation strategies and bacterial targets for polysaccharidases' discovery.

What lies on macroalgal surface: diversity of polysaccharide degraders in culturable epiphytic bacteria / M. Barbato, V.F. Vacchini, A.H. Engelen, G. Patania, F. Mapelli, S. Borin, E.S. Crotti. - In: AMB EXPRESS. - ISSN 2191-0855. - 12:1(2022 Dec), pp. 98.1-98.16. [10.1186/s13568-022-01440-8]

What lies on macroalgal surface: diversity of polysaccharide degraders in culturable epiphytic bacteria

M. Barbato
Primo
;
V.F. Vacchini
Secondo
;
G. Patania;F. Mapelli;S. Borin
Penultimo
;
E.S. Crotti
Ultimo
2022

Abstract

Macroalgal surface constitutes a peculiar ecological niche and an advantageous substratum for microorganisms able to degrade the wide diversity of algal glycans. The degrading enzymatic activities of macroalgal epiphytes are of paramount interest for the industrial by-product sector and biomass resource applications. We characterized the polysaccharide hydrolytic profile of bacterial isolates obtained from three macroalgal species: the red macroalgae Asparagopsis taxiformis and Sphaerococcus coronopifolius (Rhodophyceae) and the brown Halopteris scoparia (Phaeophyceae), sampled in South Portugal. Bacterial enrichment cultures supplemented with chlorinated aliphatic compounds, typically released by marine algae, were established using as inoculum the decaying biomass of the three macroalgae, obtaining a collection of 634 bacterial strains. Although collected from the same site and exposed to the same seawater seeding microbiota, macroalgal cultivable bacterial communities in terms of functional and phylogenetic diversity showed host specificity. Isolates were tested for the hydrolysis of starch, pectin, alginate and agar, exhibiting a different hydrolytic potential according to their host: A. taxiformis showed the highest percentage of active isolates (91%), followed by S. coronopifolius (54%) and H. scoparia (46%). Only 30% of the isolates were able to degrade starch, while the other polymers were degraded by 55-58% of the isolates. Interestingly, several isolates showed promiscuous capacities to hydrolyze more than one polysaccharide. The isolate functional fingerprint was statistically correlated to bacterial phylogeny, host species and enrichment medium. In conclusion, this work depicts macroalgae as holobionts with an associated microbiota of interest for blue biotechnologies, suggesting isolation strategies and bacterial targets for polysaccharidases' discovery.
Bioprospecting; Blue biotechnology; Cultivable microbiota; Epibiota; Polysaccharidases; Seaweeds;
Settore AGR/16 - Microbiologia Agraria
H20_RIA15SBORI_M - Industrial Applications of Marine Enzymes: Innovative screening and expression platforms to discover and use the functional protein diversity from the sea - BORIN, SARA - H20_RIA - Horizon 2020_Research & Innovation Action/Innovation Action - 2015
27-lug-2022
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/935367
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