Complete genome of Thalassotalea piscium NK451B, an Antarctic bacterium with abundant extracellular proteases

Thalassotalea piscium NK451B is a cold-adapted marine bacterium isolated from Antarctic red algae, exhibiting remarkable extracellular proteolytic activity against gelatin, casein, and collagen. In this study, we present the complete genome sequence of strain NK451B, which consists of a single circular chromosome of 4,233,832 bp with a G + C content of 36.79 % and no plasmid. Genome annotation revealed 3776 predicted protein-coding genes, 67 tRNA genes, and 16 rRNA genes. Functional analysis using the MEROPS database identified 73 putative protease-encoding genes, including 50 predicted intracellular proteases and 23 predicted extracellular proteases based on signal peptide analysis. These proteases are classified into five categories based on their catalytic types, with metalloproteinases and serine proteases being the most prevalent. These enzymes are presumed to contribute to the strain's adaptation by enabling the degradation of environmental proteins as sources of carbon and nitrogen. Overall, the genomic insights highlight the biotechnological potential of Thalassotalea piscium NK451B and enhance our understanding of its ecological role in Antarctic marine environments.