Transcriptomics‐guided identification of an algicidal protease of the marine bacterium Kordia algicida OT‐1

Abstract

In recent years, interest in algicidal bacteria has risen due to their ecological importance and their potential as biotic regulators of harmful algal blooms. Algicidal bacteria shape the plankton communities of the oceans by inhibiting or lysing microalgae and by consuming the released nutrients. Kordia algicida strain OT‐1 is a model marine algicidal bacterium that was isolated from a bloom of the diatom Skeletonema costatum. Previous work has suggested that algicidal activity is mediated by secreted proteases. Here, we utilize a transcriptomics‐guided approach to identify the serine protease gene KAOT1_RS09515, hereby named alpA1 as a key element in the algicidal activity of K. algicida. The protease AlpA1 was expressed and purified from a heterologous host and used in in vitro bioassays to validate its activity. We also show that K. algicida is the only algicidal species within a group of four members of the Kordia genus. The identification of this algicidal protease opens the possibility of real‐time monitoring of the ecological impact of algicidal bacteria in natural phytoplankton blooms.

Purification and Properties of a Plasmin-like Marine Protease from Clamworm (Perinereis aibuhitensis)

“…Due to the particular living environment, marine organisms have generated bioactive substances with significant specialization [3], especially enzymes, which have properties related to their living environment, such as thermal stability, salt tolerance, cold adaptation, etc., and offer good prospects for industrial applications [4] and biomedicine [5]. Marine organisms are important resources for the production of enzymes, and through isolation and purification from marine microorganisms, a variety of enzymes have been obtained, which exhibit antimicrobial activity [3,[6][7][8], hydrolytic activity against blood proteins [9], collagen solubilizing activity [10] and hydrolysis of alginate for efficient production of alginate oligosaccharides [11], and others. In addition to microorganisms, there are also a wide variety of enzymes, such as cellulases [12] and digestive enzymes [13], in marine animals and plants.…”