Biofloc technology for sustainable aquaculture: Microbial regulation, nutrient dynamics, and integrated system approaches

Abstract

Biofloc Technology (BFT) stands out as a groundbreaking and sustainable method in aquaculture, adept at improving water quality, drastically reducing environmental discharge, and boosting the yield of fish and shellfish. This review offers an extensive look at BFT, dissecting its core principles and spotlighting key design considerations: constant aeration, strategic water retention, tank design, and systems that require little to no water exchange. It also delves into the critical operational factors that drive microbial floc formation and nutrient assimilation, such as the ideal carbon-to-nitrogen ratio (typically between 10:1 and 20:1), optimal stocking densities, dissolved oxygen levels, pH control (6.5-8.5), and alkalinity maintenance (above 100 mg/L). The discussion extends to the varied organic carbon sources utilized (like jaggery, molasses, and rice bran) and the vital role probiotics play in nurturing beneficial microbial communities for healthier, faster-growing aquatic species. The document meticulously examines how the system's setup (indoor or outdoor), the chosen species, growth outcomes, and health indicators (including body composition and tissue analysis) are influenced. Furthermore, it underscores BFT's capacity for circular and resilient aquaculture, showcasing its integration with efficient systems like aquaponics, hydroponics, periphyton substrates, and biochar. Current hurdles, such as system instability, foaming, and intricate operations, are acknowledged, alongside a forward-looking perspective on scaling and optimizing the technology.