Enhanced Phenanthrene Biodegradation by Bacillus brevis Using Response Surface Methodology

The current investigation assessed the capability of a well-adapted and enriched bacterial strain known as Bacillus brevis for the biodegradation of phenanthrene. To enhance the removal efficiency of phenanthrene, employed Response Surface Methodology (RSM) in conjunction with a Box-Behnken design (BBD) model. The experiments were designed to explore the impact of pH (6.0 to 9.0), temperature (20 to 40°C), initial phenanthrene concentration (50 and 100 ppm), and incubation time (7 to 21 days) on biodegradation of phenanthrene. The highest level of phenanthrene biodegradation, approximately 55.0%, was achieved by Bacillus brevis when the optimal conditions were met as pH of 7.0, temperature 30oC, and initial phenanthrene concentration (70 ppm) after 21 days of incubation time. This study underscores the significance of employing statistical tools like RSM to enhance the microbial degradation of contaminants.