Coumarin degrading microorganisms isolated from Egyptian soil

Coumarins, an old class of compounds, are naturally occurring benzopyrene derivatives. A lot of coumarins have been identified from both natural and synthetic sources. Coumarins have recently attracted intense interest because of their diverse pharmacological properties. However their cytotoxicity and accumulation in the environment have become a controversial and limiting issue. Biodegradation seems as an attractive solution to reduce their toxicity or promote safer derivatives for medical applications. In our study, coumarin degrading bacteria were screened using Minimal salt media with coumarin as a sole carbon source. A total of 23 coumarin decomposing strains were isolated from 41 soil samples previously sprayed with herbicides using 0.1% coumarin. The bacterial isolate Pseudomonas fluorescens SZ1 showed the best growth when tested against higher coumarin concentrations (0.1%-0.5%) and was furthermore identified using morphological and biochemical tests.. The bacterial isolate SZ1 was identified as a Pseudomonas fluorescens strain and assumed to be a potential strong coumarin degrading strain which may be used in further industrial and medical applications. In conclusion, the aim of the study was to screen potential coumarin degrading bacteria as a biological solution to biodegrade toxic coumarin derivatives that accumulate in the environment.