Antibacterial Activity of Tunicate-Associated Bacteria from Karimunjawa Sea Against Aquaculture Pathogens | ||||
| Egyptian Journal of Aquatic Biology and Fisheries | ||||
| Article 207, Volume 29, Issue 4, July and August 2025, Page 2775-2787 PDF (673.92 K) | ||||
| DOI: 10.21608/ejabf.2025.448463 | ||||
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| Author | ||||
| Sirumapea et al. | ||||
| Abstract | ||||
| The primary challenge in shrimp aquaculture lies in pathogenic bacterial infections, which frequently result in mass mortality and substantial economic losses. Environmentally sustainable antibacterial agents are urgently needed to mitigate infections caused by Pseudomonas aeruginosa and Escherichia coli, both of which are known to induce hepatopancreatic and muscle tissue infections in shrimp. This study aimed to assess the antibacterial potential of tunicate-associated bacteria and to identify candidate antibacterial agents effective against P. aeruginosa and E. coli. A descriptive–exploratory approach was employed, including bacterial isolation using the spread plate method, purification via the streak plate method, antibacterial activity screening through agar plug diffusion, and molecular identification based on 16S rRNA gene sequencing. A total of 51 bacterial isolates were obtained from six tunicate samples, with 9.8% exhibiting antibacterial activity against at least one test pathogen. The most significant activity was observed in bacteria associated with Didemnum sp., which demonstrated an inhibition zone diameter of 11.2mm against P. aeruginosa. These findings suggest that bacterial diversity does not directly correlate with bioactive compound diversity, as the production of secondary metabolites appears to be driven by specific microbial interactions. Among the isolates, Bacillus haynesii exhibited the highest antibacterial activity, highlighting its potential as a promising candidate antibacterial agent for application in shrimp aquaculture. | ||||
| Keywords | ||||
| Antibacterial; Associated bacteria; Bacillus haynesii; Tunicate | ||||
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