Alginate degradation potential: a comparative metagenomic analysis of four cold coastal environments

MATOS, M.N.; ANSELMINO, L.; LOZADA, M.; HENRISSAT, B.; DIONISI, H.M.

Buenos Aires

Simposio; GlycoAR 2014; 2014

Up to 40% of the dry weigh of brown macroalgae are composed of alginates, linear polysaccharides that contain units of the epimers β-D-mannuronate and/or α-L-guluronate. As brown algae are abundant in cold coastal regions, these environments represent promising sources of alginate lyases. Focusing on the study of the biogeographic distribution of these genes, we analyzed 23 sediment metagenomes from 4 cold marine environments: Svalbard Archipelago (Norway, NOR), Baltic Sea (Sweden, SWE), Ushuaia Bay (Argentina, ARG) and Potter Cove (Antarctic Peninsula, ANT). We mined alginate lyase homologs in assembled sequences, searching its product name and using blast with reference sequences. We identified 2,705 gene fragments related to alginate lyases, most of them belonging to ANT (42%) and NOR (33%) sites. Using blast algorithm, we compare these sequences with all polysaccharide lyases of the CAZy database. Most of the sequences showed homology to alginate lyases belonging to the families PL7 (33%), PL17 (32%) or PL6 (21%). Interestingly, SWE samples contained a larger proportion of novel sequences (28% had e-values ≥10-10), while sequences from NOR, ANT and ARG were less divergent than those previously reported (12%, 5% and 4% had e-values ≥10-10, respectively). This study reveals a high diversity of alginate lyase sequences in sediments of these cold environments.