Purification and Characterization of Extracellular Polymeric Substances (EPS) with Antimicrobial Properties from s Marine Epibiotic Pseudoalteromonas sp.

We present a study to purify and characterize the extracellular polymeric substances (EPS) produced by Pseudoalteromonas sp. isolated from fish epidermal surface. The purified EPS was recovered from the culture supernatant by using cold ethanol precipitation and dialysis method. Colorimetric analysis of EPS revealed that it was primarily composed of proteins, 0.0251g/L, carbohydrates, 0.0561g/L and uronic acid, 0.0217 g/L. The EPS also exhibited high emulsification activity when being tested with hydrophobic substances such as paraffin oil, (94.5 % and 79.4%), kerosene, (56.1% and 37.2%) and Tween 80 (46.6% and 32.9%). In addition, the EPS demonstrated discernible antimicrobial activity against Gram-negative bacteria like E.coli, P.aeruginosa and E.aerogenes. The SDS-PAGE profile revealed up to eight types of unknown proteins were detected within the EPS, with the molecular weight ranging from 15.486 kDa to 113.058 kDa. The results of the study would contribute to the elucidation of antimicrobial components and its mechanism in Pseudoalteromonas sp.