ABSTRACT
Aims: Pseudoalteromonas ruthenica KLPp3 is the marine Gram-negative strain isolated from the surface of mud crab at Pulau Perhentian Malaysia. In this work, the anti-biofilm activity of P. ruthenica supernatant was examined on Serratia marcescen and Vibrio alginolyticus. Methodology and results: The crude extract of P. ruthenica KLPp3 was obtained using ethyl acetate. The subminimum inhibitory concentration (MIC) of the crude extract was determined using the minimum inhibitory test. The subMIC crude extract was tested against two of the S. marcescen virulence factors, which are the swarming ability and production of prodigiosin. The crystal violet assay was used to test the anti-biofilm activity of the sub-MIC crude extract against S. marcescen and V. alginolyticus. The productions of prodigiosin were reduced by 72%. The swarming area was reduced by 56.06%. It inhibits 26.9% and 48.5% of biofilm production in S. marcescens and V. alginolyticus respectively. The crude extract was heat stable. Conclusion, significance and impact of study: Besides combating the S. marcescens virulence factor, P. ruthenica KLPp3 crude extract in sub-MIC reduces the formation of biofilm of S. marcescens and V. alginolyticus, which may find applications in biofilm inhibition and prevention.