Isolation and characterization of heterocyclic hydrocarbon degrading bacteria from mangrove environment

Heterocyclic hydrocarbons and other PAHs are commonly detected in the polluted groundwater, seawater, marine, sediments soil sites. They are toxic and carcinogenic in nature as well as recalcitrant in the environment. The common members of hydrocarbons are carbazole (CAR), dibenzothiophene (DBT) and dibenzofuran (DBF) and Fluorene (FN). Microbial degradation has been an effective means to remove and transform the harmful hydrocarbons into innocuous end products. In past study, most heterocyclic degrading bacteria belong to the genera of Pseudomonas and Sphingomonas. Five bacteria strains that are capable of utilizing heterocyclic hydrocarbons as sole carbon source had been isolated from mangrove soil samples. The two tested strains involving in identification tests show different reactions to Gram staining, catalase test, citrate utilization test and motility test, while same reactions to MRVP test and indole test. The bacteria isolates show better growth at 0%,2% and 6% NaCI concentrations, while optimal growth was recorded at 6% salinity. This indicated the bacteria isolates are moderately halophilic. In addition, the DBF utilizing bacterial isolate, F002 was capable to degrade DBT, CAR and FN at the same time. However, the growth is poor and the occurrence of clear zone is beyond observation in the time allocated. At the end of this project, isolation of bacteria with ability to degrade heterocyclic hydrocarbons as sole carbon sources leads to the optimization and steering of bioremediation for contaminated environments or oil spill sites