PHENANTHRENE BIODEGRADATION BY ISOLATED STRAINS-KINETIC STUDIES

摘要

Two bacterial Strains were isolated from petroleum contaminated soil with phenanthrene as sole energy and carbon source. Biochemical and 16S rRNA gene sequence analysis confirmed the strains to be Bacillus sp. MVMB4 and Rhodopseudomonas sp. MVMB5. The effect of inoculum concentration (2.0 to 6.0 % (v/v)), pH (6.0 to 7.5) and substrate concentration (20- 100 mg/l) on the biodegradation of phenanthrene by the two strains were experimented considering bacterial growth and phenanthrene concentrations as measured parameters. The optimum inoculum concentration and pH for both the strains were same which was 4.0 % (v/v) and 7.0 respectively. But, the optimum initial phenanthrene concentrations was 60 mg/l for strain MVMB4 which was slightly greater when compared to strain MVMB5 (40 mg/l). Five kinetic models were applied to the experimental growth data to predict substrate inhibition on growth of the microorganism using MATLAB? 7.0. It is evident that the kinetic constants obtained coincided well with the literature. Thus the isolated bacterial strains Bacillus sp. and Rhodopseudomonas sp. seems to be promising strains for using in the processes of the bioaugmentation because of their ability to degrade phenanthrene and to grow on the substrate.