A Study on Screening and Characterization of Algal Antimicrobials Act against the Aquatic Bacterial Pathogens Infecting Marine Shrimp, Penaeus Monodon (Fabricius 1798)

By : Serine Michael M. , Alrich Michael M. , Mahesh T. C. , Citarasu T. , Michael Babu. M.

Page No: 26-42

Abstract
Shrimp aquaculture is a major contributor to India's export revenue but is severely affected by bacterial diseases. This study screened bioactive compounds from marine microalgae—Chlorella vulgaris, Dunaliella salina, and Nannochloropsis oculata—for antibacterial activity against shrimp pathogens (Bacillus cereus, Pseudomonas aeruginosa, Vibrio harveyi, V. alginolyticus, and Aeromonas hydrophila). Organic solvent extracts were tested, with the butanolic extract of N. oculata showing the strongest broad-spectrum activity. Phytochemical analysis revealed the presence of flavonoids, phytosterols, phenolics, alkaloids, and terpenoids. Column chromatography and FTIR confirmed functional groups (-COOH and -NO₂), and TLC showed a single active compound (Rf = 0.82). MIC and MBC were 8 μg and 12 μg, respectively, with the compound causing cell wall damage in pathogens. In vivo tests using Penaeus monodon confirmed the compound’s efficacy. This study highlights the potential of N. oculata as a natural antibacterial agent in shrimp aquaculture.

Authors :
Serine Michael M.And Mahesh T. C.: Research Department of Zoology, Vivekananda College, Kanyakumari District, Tamil Nadu, India.
Alrich Michael M. : Research Department of Zoology, St. Hindu College, Nagercoil, Tamil Nadu, India.
Citarasu T. And Michael Babu. M. : Centre for Marine Science and Technology, Manonmaniam Sundaranar University, Rajakkamangalam, Kanyakumari District, Tamil Nadu, India.
 

DOI: http://doi.org/10.32381/JAT.2025.40.1-4.5