Production, Purification and Characterization of Extracellular Polymeric Substances from Biofilm Forming Marine Bacteria

Abstract

The marine environment is home to different bacteria that can be exploited to produce useful compounds such as extracellular polymeric substances. EPS is currently being used as a promising biopolymer in a wide range of biotechnological applications due to its unique biological features. EPS secreted by bacterial strains BM14 and RM26 were isolated, purified, and characterised in this study. The bacterial strains BM14 and RM26 produced 1126.0 mg L-1 and 1187.2 mg L-1 of EPS, respectively. The total sugar content of BM14 and RM26 extracted EPS was found to be 50.14 µg mg-1 and 122.75 µg mg-1 respectively. Antimicrobial susceptibility assay for bacteria determined the sensitivity of particular antibiotics to bacterium and both the strains showed sensitivity to all the antibiotics tested. SEM analysis of EPS produced by BM14 and RM26 was observed to be amorphous in nature. Both EPSs exhibited strong antibacterial activity against seven pathogenic bacteria: Pseudomonas putida, Serratia liquifaciens, Escherichia coli, Serratia marcense, Klebsiella pneumoniae and Pseudomonas auregenosa in vitro. Elemental analysis by EDX confirms the presence of carbon content to be higher in EPS produced by BM14 and RM26. The bacteria selected for the current study, BM14 and RM26 were already identified by 16S rRNA gene sequencing as Staphylococcus warneri and Bacillus megaterium respectively. The heterogenous features of EPS that were discovered in this study could be used in various biotechnological applications.