Bacteria from Jatropha curcas rhizosphere, degrades aromatic hydrocarbons and promotes growth in Zea mays

Abstract

The rhizosphere is one of the most important reservoirs of microorganisms. Because of the microbial metabolic activities, these can be used for various biotechnological, agricultural and environmental purposes. In this study we evaluated five genetically related bacterial strains; Pseudomonas aeruginosa N7B1 (MG457074), Pseudomonas sp. (MG457075), Pseudomonas sp., Bf1 (MG457076) and Pseudomonas aeruginosa F23 (MG457077), isolated from Jatropha curcas rhizosphere, capable of growing and degradating benzene and phenanthrene. The hydrocarbon degradation by these strains was quantified by gas chromatography coupled to mass spectrophotometry. The Pseudomonas aeruginosa N7B1 strain removed 84% of phenanthrene and 45% of benzene in a seven-day period, while the other strains showed a lower hydrocarbon degradation capacity. Another biotechno-logical feature of these strains is maize growth promotion, in a substrate enriched with 0.5% of phenanthrene and 1.0% of benzene. Pseudomonas aeruginosa N7B1 and Pseudomonas aeruginosa F23 showed an increase in root and shoot fresh and dry weight, plant height and root length variables. These results open the possible use of these strains as bioinoculants to promote the growth of maize plants in phenanthrene and benzene polluted soils.

Keywords

• pseudomonas
• phenanthrene
• benzene
• growth promotion
• biodegradation