Isolation, screening and efficiency of Pseudomonas isolates in biofilm formation on organic and inorganic carriers and phenanthrene bioremediation

Microbial biofilms are one of the most important microorganism’s forms of life in the environment. The aim of this study was to use native Pseudomonas aeruginosa in biofilm form to clean up phenanthrene.

Among 63 Pseudomonas isolates from Iranian soil, bacterial isolate with high potency in biofilm formation and crude oil degradation was selected and genetically identified. The effect of inorganic (raw pumice, processed pumice and perlite) and organic (biochar and sugarcanes bagasse) carriers on biofilm formation was investigated. Biofilm structure was studied by scanning electron microscopy. Also, the effects of two growth form (biofilm, planktonic) on biochar carrier on laccase production and phenanthrene degradation in liquid media was investigated.

Purified Pseudomonas isolates were screened based on biofilm formation and crude oil degradation. B59 (Pseudomonas aeruginosa) with 56.62% showed the highest percentage of crude oil degradation. Highest and lowest CFU belonged to biochar and processed pumice with 8.8 and 2.9 respectively. Laccase activity was measured in biofilm form and planktonic form 39.8 and 33.1 Um-1 respectively. Biofilm form of Pseudomonas aeruginosa led to 97.17% phenanthrene degradation where planktonic form reached 91.37%.

Results showed that biofilm form of Pseudomonas aeruginosa compared to planktonic form by significant increase in CFU and laccase activity result in more phenanthrene degradation in liquid media.