Abstract Biofloc technology (BFT) relies on EPS-producing heterotrophic bacteria to initiate biofloc aggregation, improving nutrient recycling and microbial stability in aquaculture systems. However, commercial starter cultures may perform inconsistently under local conditions, and information on indigenous EPS-forming bacteria remains limited. Therefore, this study aimed to identify indigenous EPS-producing bacteria from shrimp pond sediments with potential as candidate biofloc starter isolates. Heterotrophic bacteria isolated and purified from pond sediments were screened for EPS production using a microtiter-plate assay and subsequently evaluated for biofloc formation in a laboratory-scale jar assay with a 450 mL working volume for 7 days. High-performing isolates were then identified using morphological and biochemical analyses. Three isolates, B1, B3, and B4, showed EPS production and successfully induced biofloc formation. Among these isolates, B4 showed superior performance by initiating floc formation within four days, producing the largest flocs, 889 µm, the highest floc volume, 245 mL L⁻¹, and the richest microscopically observed floc-associated assemblage. Under the conditions of this short-term laboratory screening assay, Bacillus sp. B4 represents a promising indigenous candidate for further biofloc starter development. However, this isolate requires molecular identification and validation in longer-term tank- or pond-scale trials with shrimp.
Amin et al. (Thu,) studied this question.