Biofilm and Microbial Community Dynamics in Aquaculture Bioreactors for Water Quality Control: Current Status and Future Directions

A biofilm in aquaculture is a community of microorganisms, including bacteria, algae, fungi, and others, that forms a complex and structured layer attached to surfaces within water systems. Aquaculture bioreactors rely on biofilms as critical microbial consortia that drive water quality improvement through nutrient cycling and organic matter degradation. This review highlights the dynamic succession and diversity within biofilm microbial communities, particularly emphasizing key bacterial groups such as Planctomycetes, Bacteroidetes, nitrifiers, and denitrifies that mediate ammonia and nitrogen removal. Biofilms form robust structures through sequential attachment, growth, and maturation stages, influenced by physical and chemical parameters. Molecular tools like 16S rRNA gene sequencing have advanced our understanding of biofilm ecology, revealing community shifts responsive to environmental and operational conditions. Biofilms also contribute to pathogen suppression yet pose challenges through antimicrobial resistance, necessitating balanced management to optimize treatment efficiency without biomass overgrowth. Promising future directions include engineering microbial communities and incorporating probiotics to enhance functional biofilms tailored for sustainable aquaculture. This collective knowledge supports improved aquaculture sustainability by ensuring efficient water treatment, fish health, and environmental protection. Continued integration of molecular techniques and biofilm management strategies will enhance bioreactor design and operation for resilient, eco-friendly aquaculture systems. The aim of this review is to assess the role of biofilms and microbial community dynamics in aquaculture bioreactors for effective water quality control and sustainable aquaculture production.