Abstract
In this study, 9 bacterial strains were collected from the surface of seaweeds (Sargassum sp., Gracillaria sp. and Ulva sp.) and screened for their antibacterial activity against three biofilm forming bacteria. All the 9 strains inhibited the growth of biofilm-forming bacteria and the best active strains were selected for in vitro and in vivo biofilm control assays. The results showed that the extract of strain S8 controlled the biofilm formation considerably. The toxicity of bacterial extracts was studied by determining the LC50 value against Anemia sp. The LC50 values obtained were found to be 0.061 and 0.105 mg/ml for the extracts of strain Si and S8 respectively. The best active strain S8 was identified as Psendomonas taiwanensis based on 16S rRNA gene sequencing. The bioactive EPS was partially purified by TLC and HPLC analysis. Besides, the functional groups present in the EPS was analysed using FT-IR, which showed the presence of alcohol, alkenes, amines, esters and carboxylic acid groups.