Mining alginate lyases in sediment metagenomes from four geographically distant cold coastal environments

DIONISI, H. M.; MATOS, M.N.; ANSELMINO, L.; LOZADA, M.; MAC CORMACK, W.; CARROLL, J.; LUNDGREN, L; SJÖLING, S.; CHAVARRÍA, K.; HENRISSAT, B.; JANSSON, J.

Edinburgh

Congreso; 16th European Congress on Biotechnology; 2014

European Federation on Biotechnology

Brown macroalgae are considered an attractive option as sustainable feedstock for the production of biofuels and commodity chemicals due to their high carbohydrate content. Microbial communities from cold coastal environments represent promising sources of novel enzymes depolymerizing brown algal polysaccharides such as alginates, as these organisms constitute a large primary biomass in these environments. We used a nested sampling strategy to obtain sediment samples from four high-latitude coastal environments (Svalbard Archipelago, Norway; Baltic Sea, Sweden; Ushuaia Bay, Argentina and Potter Cove, Antarctica). Twenty three samples were sequenced using Illumina HiSeq? 1500, assembled and annotated using the IMG/M pipeline. The complete assembled metagenome dataset contains 5.6 Gb and 1.4 x 107 protein coding genes. With the goal of identifying alginate lyase homologs in the metagenomes, we mined this dataset using both blastp searches and product names assigned in the functional annotation. We retrieved 2,705 sequences between 100 and 1,166 amino acids in length, mostly belonging to the CAZy polysaccharide lyase families PL17 (30.4%), PL7 (28.2%) or PL6 (22.1%). When normalized with the protein coding gene numbers of the assembled metagenomes, Antarctic samples contained the highest abundance of identified sequences, and Baltic Sea samples contained a larger proportion of novel sequences (Kruskal-Wallis test, p < 0.05). Different levels of gene order conservation were found among scaffolds containing these genes, and with genomes of isolated alginate-degrading bacteria. This study revealed a large diversity of alginate lyase homologs from yet-to-be cultured marine microorganisms, which could aid in the engineering of microbial platforms for biorefineries.