Coumarin and its derivatives are heterocyclic compounds which gives toxic effects when it is used in higher quantity. In lower amount it is also toxic to marine plants and animals like fish, phytoplanktons, zooplanktons etc. According to various data it is confirmed that coumarin can be harmful for human being also though it is used in cosmetics, pharmaceutical industries and various medicines like anti-cancer and anti-coagulant. Present investigation is focused towards isolation of Pseudomonas fluorescens from different places near Rajkot area in Gujarat state and checks their activity against 7- hydroxy-4-methylcoumarin. Total 10 isolates were isolated from these soil samples from that isolates 3 were identified as Pseudomonas fluorescens per their biochemical and morphological properties and their fluorescens under UV exposure. Different biochemical and antibiotic susceptibility test were performed for all these 10 isolates. To check the activity against 7-hydroxy-4- methylcoumarin Compound was dissolved in n- propanol and was given to all 10 isolates by making well in sterile petriplates containing King’s B Base medium. Some of these organisms were resistant to the coumarin.
