Int Aquat Res https://doi.org/10.22034/IAR.2024.1997968.1528 Bacteriocin producing Bacillus and their potential applications in fsh farming Chioma Stella Anyairo . Kridsada Unban . Kalidas Shetty . Chartchai Khanongnuch Received: 04 October 2023 / Accepted: 24 February 2024 / Published online: 03 March 2024 © The Author(s) 2024 Chioma Stella Anyairo Multidisciplinary and Interdisciplinary School, Chiang Mai University, Mueang, Chiang Mai, 50100, Thailand Multidisciplinary and Interdisciplinary School, Chiang Mai University, Mueang, Chiang Mai, 50100, Thailand Kridsada Unban Division of Food Science and Technology, School of Agro-Industry, Faculty of Agro-Industry, Chiang Mai University, Mueang, Chiang Mai, 50100, Thailand Kalidas Shetty Department of Plant Sciences, North Dakota State University, Fargo, ND 58105, USA Chartchai Khanongnuch ( ) Research Center for Multidisciplinary Approaches to Miang, Multidisciplinary Research Institute (MDRI), Chiang Mai University, Mueang, Chiang Mai 50200, Thailand Research Center of Microbial Diversity and Sustainable Utilization, Chiang Mai University, Mueang, Chiang Mai 50200, Thailand e-mail: ck_biot@yahoo.com e-mail: ck_biot@yahoo.com REVIEW Abstract Studies on the bacteriocins of Bacillus species are increasing due to enhanced research interests and benefts for diverse applications ranging from bio-preservatives to probiotics, providing natural antimicrobial functions in fsh farming and related aquaculture production needs. These benefts are due to their broad spectrum of antimicrobial activity and mode of action, their ability to secrete these important peptides in large amounts (g/L level) in a culture medium, and the ubiquitous nature of producing strains. It is well known that fsh farming industries are challenged with pathogenic infection, indiscriminate antibiotic use, and now linked to antibiotic resistance of pathogens due to poor sewage disposals and persistence in nature. To overcome these challenges and the quest to stop the unregulated use of conventional antibiotics in fsh farming industries has encouraged studies toward more eco-friendly options such as probiotics and associated bacteriocins with antimicrobial potential. Therefore, this review summarized and discussed recent studies on the efectiveness of Bacillus strains probiotic application in fsh farming, emphasizing the importance of their proper characterization, extended feld trials and the need for specifcations in the selection criteria of the potential Bacillus probiotic strains of interest before further investigations, approvals and registrations. Keywords Aquaculture . Antimicrobials . Probiotics Introduction Fish farming and related aquaculture production systems are robust global agricultural sectors contributing to food security, better nutrition and health with benefts of added economic value from a range of food products. One of the major challenges to sustainable advances in this sector is that it is afected by infec- tious pathogenic microbes (A. hydrophila, S. agalactiae, A. salmonicida, P. fuorescens, Vibrio spp. and others.), which can result in fsh production underperformance and losses from death in severe cases af- fecting farmers and associated production system of aquaculture (Banerjee et al. 2017; Haenen et al. 2023; Sanches-Fernandes et al. 2022). Of the techniques adopted by farmers (improved sanitation, light and water control and others) against these pathogens, antibiotics usage was a signifcant breakthrough in controlling