Biocontrol Potential of Serratia Marcescens (B8) and sp. (B13) Isolated from Urban Mangroves in Raposa, Brazil.

This study analyzed the antifungal potential of 16 bacterial strains isolated from mangrove sediment. Bacterial selection was conducted in a solid medium. This was followed by the production and extraction of metabolites using ethyl acetate to evaluate chitinase production, antifungal activity, and toxicity toward and . Bacterial strains B8, B11, and B13 produced the largest inhibition halos (>30 mm) toward , , and fungi. Strains B1, B3, B6, B8, B11, B13, B14, and B16 produced chitinases. In assays using liquid media, B8 and B13 produced the largest inhibition halos. Exposing the fungal inocula to metabolic extracts of strains B6, B8, B11, B13, B14, B15, and B16 caused micromorphological alterations in the inocula, culminating in the inhibition of sporulation and spore germination. Toxicity tests using and revealed that the metabolites showed low toxicity. Six of the bacterial strains were molecularly identified to species levels, and a further two to genus level. These included (B8), which exhibited activity in all tests. Mangroves provide a useful resource for the isolation of microorganisms for biocontrol. Among the isolates, and spp. showed the greatest potential to produce metabolites for use as biocontrol agents in agriculture.