Petroleum degradation by endophytic Streptomyces spp. isolated from plants grown in contaminated soil of southern Algeria

Petroleum hydrocarbons are well known by their high toxicity and recalcitrant properties. Their increasing utilization around worldwide led to environmental contamination. Phytoremediation using plant-associated microbe is an interesting approach for petroleum degradation and actinobacteria have a great potential for that. For this purpose, our study aimed to isolate, characterize, and assess the ability of endophytic actinobacteria to degrade crude petroleum, as well as to produce plant growth promoting traits. Seventeen endophytic actinobacteria were isolated from roots of plants grown naturally in sandy contaminated soil. Among them, six isolates were selected on the basis of their tolerance to petroleum on solid minimal medium and characterized by 16S rDNA gene sequencing. All petroleum-tolerant isolates belonged to the Streptomyces genus. Determination by crude oil degradation by gas chromatorgraph-flame ionization detector revealed that five strains could use petroleum as sole carbon and energy source and the petroleum removal achieved up to 98% after 7 days of incubation. These isolates displayed an important role in the degradation of the n-alkanes (C6-C30), aromatic and polycyclic aromatic hydrocarbons. All strains showed a wide range of plant growth promoting features such as siderophores, phosphate solubilization, 1-aminocyclopropane-1-carboxylate deaminase, nitrogen fixation and indole-3-acetic acid production as well as biosurfactant production. This is the first study highlighting the petroleum degradation ability and plant growth promoting attributes of endophytic Streptomyces. The finding suggests that the endophytic actinobacteria isolated are promising candidates for improving phytoremediation efficiency of petroleum contaminated soil.Fil: Baoune, Hafida. No especifíca;Fil: Ould El Hadj-Khelil, Aminata. No especifíca;Fil: Pucci, Graciela. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Sineli, Pedro Eugenio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Loucif, Lotfi. No especifíca;Fil: Polti, Marta Alejandra. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentin

Bioremediation of petroleum-contaminated soils using Streptomyces sp. Hlh1

Purpose Bioremediation using microorganisms is a promising strategy to remediate soil with petroleum hydrocarbons.Streptomycessp. Hlh1, an endophytic strain, has previously demonstrated the ability to degrade crude petroleum in liquid culture.To apply this strain at field scale, it is necessary to test its ability to colonize the soil, compete with native microbiota, and removethe petroleum hydrocarbons under unfavorable conditions. Herein, a study was conducted to evaluate the performance ofStreptomyces sp. Hlh1 to remove crude petroleum from contaminated sterilized and non-sterilized soils.Materials and methods Soils samples, contaminated with 2%, 5%, and 10% of petroleum, were inoculated with Streptomycessp.Hlh1, and incubated at 30 °C for 4 weeks. At the end of bioremediation assays, the pollutant concentrations were determined byGas chromatography flame ionization detector and the degradation rates were also calculated. The survival of the strain in the soilwas estimated and the toxicity of metabolites was evaluated on Lactuca sativa.Results and discussion Streptomyces sp. Hlh1 was able to grow and remove total petroleum hydrocarbons (TPH), n-alkanes, andaromatic hydrocarbons found in soil samples. In sterilized soil samples, Streptomyces sp. Hlh1 removed up to 40% of TPH at aninitial concentration of 10%. Whereas, the maximum TPH removal reached was 55% in non-sterilized soil at an initial concentration of 2%. In addition, it was observed that the degradation of aromatic hydrocarbons was more active than n-alkanes. Thestrain grew well and produced high biomass in contaminated soil. Lettuce seedling was found to be the adequate bioindicator toassess the toxicity of petroleum end products. Streptomyces sp. Hlh1 performed a successful bioremediation, which was confirmed through the phytotoxicity test.Conclusions The study shows the first insight of the contribution of free endophytic actinobacterial strain in the bioremediation ofpetroleum-contaminated soil; therefore, it suggests that Streptomyces sp. Hl1 can be usefully exploited at field scale.Fil: Baoune, Hafida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Université Kasdi Merbah Ouragla; ArgeliaFil: Aparicio, Juan Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Pucci, Graciela. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Ould El Hadj-Khelil, Aminata. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Université Kasdi Merbah Ouragla; ArgeliaFil: Polti, Marta Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentin

Effectiveness of the Zea mays-Streptomyces association for the phytoremediation of petroleum hydrocarbons impacted soils

Restoring polluted sites by petroleum hydrocarbons is a challenge because of their complexity and persistence in the environment. The main objective of the present study was to investigate the performance of plant-actinobacteria system for the remediation of crude petroleum and pure-polycyclic aromatic hydrocarbons (PAHs) contaminated soils. The endophytic strain Streptomyces sp. Hlh1 was tested for its ability to degrade model PAHs (phenanthrene, pyrene and anthracene) in liquid minimal medium. Streptomyces sp. Hlh1 demonstrated the ability to grow on PAHs as sole carbon and energy source, reaching hydrocarbons removal of 63%, 93% and 83% for phenanthrene, pyrene and anthracene, respectively. Maize plant was chosen to study the impact of Streptomyces sp. Hlh1 inoculation on the dissipation of contaminants and plant growth. Thus, maize seedlings grown in soils contaminated with crude petroleum and pure-PAHs were inoculated with Streptomyces sp. Hlh1. Results showed that the endophyte inoculation increased contaminants removal. Maximum hydrocarbons removal (70%) was achieved in inoculated and planted soil contaminated with crude oil, while 61%, 59%, and 46% of hydrocarbons dissipation were registered for phenanthrene, pyrene and anthracene, respectively. These degradations rates were significantly higher compared to non-inoculated systems in all the treatments evaluated. Further, it was revealed that hydrocarbons (C8–C30) were efficiently degraded in plant-Streptomyces Hlh1 system. Moreover, the inoculation with the actinobacteria resulted significant plant development and enhanced photosynthetic pigments compared to plants grown in the other experimental conditions. The present study provide evidence that the inoculation of maize plants with Streptomyces sp. Hlh1 play a remarkable role in the removal of petroleum hydrocarbons, enhancing plant development in contaminated soils.Fil: Baoune, Hafida. Laboratoire de Protection Des Écosystème En Zones Aride; ArgeliaFil: Aparicio, Juan Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Acuña, Adrian Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Tecnológica Nacional. Facultad Regional Santa Cruz. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia de Santa Cruz; ArgentinaFil: El Hadj-khelil, Aminata Ould. Laboratoire de Protection Des Écosystème En Zones Aride; ArgeliaFil: Sanchez, Leandro Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Polti, Marta Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Alvarez, Analia. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentin