Harnessing Marine Bacterial Lipopeptides for Sustainable Disease Management in Open Sea Cage Aquaculture

The open ocean cage aquaculture system is facing considerable challenges with disease outbreaks resulting from over-farming and the rise of resistance to antimicrobial treatment. Although antibiotics can deal with some health issues, they have other implications for the environment, so more judicious options are warranted. Lipopeptides, which are a compound that can be produced by marine bacteria such as Bacillus amyloliquefaciens or Bacillus subtilis, could represent a new solution, and this review will assess their feasibility. Lipopeptides, including surfactins, fengycins, iturins, and the clinically-used daptomycin, have notable antiviral, antifungal, and antimicrobial properties, and can have positive effects on the immune system. Notably, lipopeptides have a remarkable antioxidant profile, and have excellent free radical scavenging ability, making them interesting candidates for improving disease resistance in fish relating to oxidative stress. The surfactins and iturins have amphiphilic structure and can destabilize pathogen cell membranes, inhibit biofilm formation and elicit host immune responses. This completely changes the game with regards to multi targeting pathogens of aquaculture like Vibrio spp. and Aeromonas spp. Surfactins and iturins show broad-spectrum activity while fengycins are selectively active against fungal threats. Daptomycin, which is primarily derived from Streptomyces, demonstrates the potential of the lipopeptide class to develop therapeutically, which is something that tends to be overlooked. Unlike synthetic antibiotics, they are also biodegradable therefore there is much less environmental impact from lipopeptides. The complexity of the structure may have also some impact on the rate of development of resistance, if any. Their commercialization is possible however, the main hurdles that need to be solved to improve aquaculture are the biologically scalable production, the economically viable purification, and the stability for practical application at sea. Fast-evolving fermentation techniques, genetic manipulation and the use of nanodrug systems have the potential to enhance aquaculture processes and productivity, and treatment. Implementing lipopeptides into disease management systems could also ensure the sustainability of open ocean cage aquaculture and reduce unnecessary antibiotic application. This review has drawn attention to an area that has immense value, the marine lipopeptides, and as it is clear from this review that we need multiple disciplines to work create user-friendly pathways to transition research into action to address global aquaculture sustainability.