Majority of microbial infections occurring in the human body are attributed to be biofilm-mediated. Biofilms formations in industrial settings are associated with many problems. Formation of biofilm is controlled by environmental factors. This study is carried out to determine the biofilm formation in Serratia marcescens under different environmental condition. Biofilm assay in nutrient medium by microtitre plate methods under different test conditions were performed. Using a microplate assay with crystal violet staining, we examined biofilm formation by 30 strains in nutrient broth with different temperatures (fridge temperature, Room temperature and 37◦C), at different pH (4.5, 7.0 and 8.5) and with varying concentrations of sodium chloride (0.5%, 1% and 2%). The synergistic effect on biofilm formation was observed for temperature, pH and salt concentration. The strains produced more biofilm at fridge temperature than at RT and 37◦C. Biofilm production at pH 4.5, 7 and 8.5 was comparable but significantly higher at pH 4.5. This study also demonstrated the influence of NaCl on biofilm formation.
