Aislamiento e identificación microbiológica de consorcios de bacillus aislados del manglar de puerto hualtaco para su uso en acuicultura.

Abstract

This study aimed to isolate and identify Bacillus strains from mangrove sediments in Puerto Hualtaco, Ecuador, to evaluate their potential in aquaculture applications, as well as to analyze the microbial communities present. Sediments were collected at three representative sites (shrimp farm gate, virgin mangrove, and dock). In the laboratory, samples were divided into two groups: controls (without inputs) and treatments enriched with molasses (84 mg/L) and silicate (34 mg/L). After 7 days, microbiological analyses were performed for strain isolation and metagenomic analyses to characterize the bacterial communities. The microbiological isolation of Bacillus was carried out by culture on chromogenic agar, followed by biochemical tests (Gram, catalase, spores, among others), growth tests at different pH and salinity levels, and Vibrio inhibition assays. Nine strains of Bacillus were identified, all Gram-positive, catalase-positive, with active motility and the ability to hydrolyze proteins; in addition, some showed high tolerance to extreme conditions of salinity and pH. In the inhibition assays, certain strains presented antagonistic activity against Vibrio, highlighting their potential as aquaculture probiotics. Metagenomic analysis revealed that the addition of inputs significantly altered the microbial communities, evidencing their sensitivity and adaptability. Shrimp farm gates presented the greatest diversity of Bacillus strains. These results highlight the value of mangroves as a source of strains with probiotic applications, and underline the importance of understanding microbial interactions and their response to aquaculture practices in complex ecosystems such as mangroves.