Isolation and characterization of Pseudomonas aeruginosa and Brevibacillus species and their potential to biodegrade polyethylene material

Abstract

This study was conducted to screen for Pseudomonas aeruginosa and Brevibacillus species from soil and investigate their ability to biodegrade low density polyethylene materials. The organisms were isolated using phenotypic characterization and molecular identification by polymerase chain reaction (PCR). The PCR confirmed the presence of two different strains of Pseudomonas aeruginosa and absence of Brevibacillus specie from the soil sample. The bacteria were inoculated in a nutrient broth to which 2% polyethylene was amended for a period of three weeks in a shaker incubator at 180rpm. Effect of temperature, pH and concentration of polyethylene on the biodegradation process was also studied. The initial and final dry weights of the polyethylene were recorded and the % degraded was calculated. It was found that both strains of Pseudomonas aeruginosa were capable of degrading the polyethylene. Strain C3 produced a maximum degradation of 20% at 37°C and pH 6. Strain B3 achieved a maximum degradation of 15% at 37°C at pH 6 and 7. In addition, it was found that both strains of Pseudomonas aeruginosa were able to survive up to 6% of polyethylene producing a maximum degradation of 55%. Therefore strains B3 and C3 of Pseudomonas aeruginosa can be effective in biodegradation of polyethylene in dump sites if their potentials are well exploited.