Multi-Trait Activity of Enterobacter Sp. Strain MHR4 towards Fluorene Degradation As Well As In Plant Growth Promotion

Abstract

Polycyclic Aromatic Hydrocarbons (PAH) are ubiquitous contaminants in environments, are generated as a by-product of incomplete combustion of organic substances. PAH continuously increases and accumulate in surrounding finally affect the environment as well as crop production. Thus, appropriate treatment is required to reduce the concentration and toxicity of these substances. Bioremediation, an effective method, uses the ability of an organism to reduce the concentration of PAH to an acceptable level. This study investigated the ability of PAHs (fluorene) degrading as well plant growth promoting activity by three bacterial strains (MHR 4 , MHR 2 and MB 2) isolated from crude oil polluted soil near fuel filling stations from Haldwani and Bhowali in Uttarakhand region. These strains showed considerable growth over fluorene, as the sole carbon source with 100-500 ppm concentration in Mineral Salt Medium (MSM) agar plates after 24 h. Although, all the strains have potential towards plant growth promoting activity. Comparative study of fluorene degradation was found prominent, 81.2% in strain MHR 4 followed by strain MB 2 , 55% and strain MHR 2 , 37.5%, likewise, the efficiencies of various PGP activities in strain MHR 4 were detected quite high. This was convincing enough to investigate the strain MHR 4 for their molecular identification and to check their efficiency in pot trail experiment. Therefore, the efficient strain MHR 4 was identified on the basis of 16S rDNA sequencing and confirmed as Enterobacter sp. The multi traits strain effectively to remove fluorene both from the oil contaminated environment as well as to eliminate the chemical fertilizer by providing diverse PGP activity, is a novel achievement and suggests that Enterobacter sp. MHR 4 have extremely useful for a biotechnological process involving fluorene degradation and plant growth promotion. The unique nature of fluorene degradation as well as plant growth promotion activity has not yet been studied in the same bacterial strain to our knowledge.