A crustin isoform from black tiger shrimp, Penaeus monodon exhibits broad spectrum anti-bacterial activity

• An isoform of crustin antimicrobial peptide was cloned and expressed from black tiger shrimp.
• Recombinant crustin exhibited broad spectrum antibacterial activity against both Gram positive and Gram negative bacteria.
• Low minimum inhibitory concentration against vibrio pathogens of shrimp showed its potential for use in aquaculture.

Crustaceans have a powerful non-specific immune mechanism that responds to pathogen invasion and together with cellular responses, generates powerful humoral factors such as antimicrobial peptides. Crustins are a diverse class of antimicrobial peptides that are expressed by the circulating haemocytes of crustaceans. Several isoforms of this molecule are reported and in this study, one isoform from the black tiger shrimp, Penaeus monodon was cloned and expressed in Escherichia coli SG 13009. The purified recombinant crustin peptide had a molecular weight of 22 kDa and exhibited potent anti-bacterial activity in vitro against several Gram positive and Gram negative bacteria that included pathogens of aquatic animals and humans. The recombinant crustin showed a minimal inhibitory concentration of 0.5 μg ml−1 against the vibrio pathogens of shrimp, which suggests its promise for application in aquaculture.