RESUMO
The oil-oxidizing potential of associative rhizobacteria of the genus Azospirillum was studied under laboratory conditions. After screening, A. brasilense strain SR80 was chosen for further investigation. The strain was capable of degrading 56.5% of crude oil (added in a concentration of 1%) over 14 days in a medium containing malate as an additional source of carbon and energy. Studies of associative properties showed that the strain had positive chemotaxis to wheat root exudates, colonized wheat roots, and produced indolyl-3-acetic acid. The synthesis of indolyl-3-acetic acid was not inhibited by oil. Under hydroponic conditions, crude oil stimulated growth of A. brasilense SR80, which promoted development of the wheat root system in the presence of oil and enhanced the level of oil degradation by the plant-microbial association.
Assuntos
Azospirillum/metabolismo , Petróleo/metabolismo , Reguladores de Crescimento de Plantas/metabolismo , Triticum/microbiologia , Azospirillum/crescimento & desenvolvimento , Biodegradação Ambiental , Quimiotaxia , Meios de Cultura , Ácidos Indolacéticos/metabolismo , Malatos , Oxirredução , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Triticum/metabolismoRESUMO
The Acinetobacter calcoaceticus strain TM-31 has been isolated from a microbial assemblage of a pilot plant purifying waste water polluted with mineral oil. This strain is capable of efficient degradation of components of mineral oil (alkanes, isoalkanes, and alkyl residues of the naphthene and arene fraction. The strain bears stably inherited plasmids of sizes 120, 9, and 8 kb, which can be transferred into plasmid-free cells of the parental strain and into bacteria of the genus Pseudomonas and ensure the degradation of hexadecane and mineral oil.