Hydrocarbon-contaminated Antarctic soil: changes in bacterial community structure during the progress of enrichment cultures with different n-alkanes as substrate

KUC V; VAZQUEZ SC; HERNANDEZ EA; MARTINEZ ALVAREZ L; VILLALBA PRIMITZ J; MAC CORMACK W.P; RUBERTO L

POLAR BIOLOGY

SPRINGER

Lugar: Berlin; Año: 2019

0722-4060

After an on-site biostimulation process of a portion of Antarctic gasoil-contaminated soil, 20% of initial hydrocarbon concentration remained undegraded (mainly C11 to C14 n-alkanes). In this work, these n-alkanes were used as substrate for enrichment cultures using the treated soil as a source of microorganisms. Three subcultures (8, 16 and 24 days) were done. Changes in bacterial communities between cultures were evidenced by Denaturing Gradient Gel Electrophoresis (DGGE). Results showed that even differences of one C in the alkane chain length led to different community structures that evolved divergently from the original one. Clusters analysis showed that samples grouped mainly by time of culture but substrate-dependent differences were also evident. Isolation of biological tools for bioremediation from the cultures showed that Pseudomonadaceae members were omnipresent whereas Rhodococcus were obtained in cultures with the longest chain-length substrates. This work provided evidence about the existence of a substrate specificity of the soil bacteria, leading to different community structures even when only small changes are introduced in the environment (a difference in only one C-atom of the alkane chain length). A collection of psychrotolerant hydrocarbon degrading strains was obtained, representing a valuable tool for the design of a bioaugmentation strategy as a second, more specific stage targeting the hydrocarbons remaining after a first bioremediation process involving biostimulation