Optimal Conditions for Naphthalene Biodegradation by Local Bacterial Isolates

Polycyclic aromatic hydrocarbons (PAHs) are non-polar organic compounds consist of two or more fused benzene rings, arranged in linear, angular or clustered structures. The present study aims to find the optimal conditions for studied bacterial isolates (PS6, DR10 and Ja.2) to degrade naphthalene in liquid BH medium using the bacterial growth and biodegradation percentage of naphthalene as indicators. The three isolate were identified as Pseudomonas putida, Burkholderia cepacia and Acinetobacter baumannii respectively according to the results obtained from biochemical tests and vitek2 system. The optimum incubation period, temperature, pH and naphthalene concentration for Pseudomonas putida, Burkholderia cepacia and Acinetobacter baumannii were determined. Results showed that the maximum growth and biodegradation for naphthalene by three isolates happened after 10 days of incubation at 35C, in BH medium adjusted to pH 7 and supplemented with 100 mg/l of naphthalene. The Pseudomonas putida gave highest biodegradation of naphthalene compared with other two isolates.