Intensification of Ex Situ Bioremediation of Soils Polluted with Used Lubricant Oils: A Comparison of Biostimulation and Bioaugmentation with a Special Focus on the Type and Size of the Inoculum

Attila Bodor, Péter Petrovszki, Ágnes Erdeiné Kis, György Erik Vincze, Krisztián Laczi, Naila Bounedjoum, Árpád Szilágyi, Balázs Szalontai, Gábor Feigl, Kornél L. Kovács, Gábor Rákhely and Katalin Perei
Additional contact information
Attila Bodor: Department of Biotechnology, University of Szeged, H-6726 Szeged, Hungary
Péter Petrovszki: Department of Biotechnology, University of Szeged, H-6726 Szeged, Hungary
Ágnes Erdeiné Kis: Department of Biotechnology, University of Szeged, H-6726 Szeged, Hungary
György Erik Vincze: Department of Biotechnology, University of Szeged, H-6726 Szeged, Hungary
Krisztián Laczi: Department of Biotechnology, University of Szeged, H-6726 Szeged, Hungary
Naila Bounedjoum: Department of Biotechnology, University of Szeged, H-6726 Szeged, Hungary
Árpád Szilágyi: Department of Biotechnology, University of Szeged, H-6726 Szeged, Hungary
Balázs Szalontai: Institute of Biophysics, Biological Research Centre, H-6726 Szeged, Hungary
Gábor Feigl: Department of Plant Biology, University of Szeged, H-6726 Szeged, Hungary
Kornél L. Kovács: Department of Biotechnology, University of Szeged, H-6726 Szeged, Hungary
Gábor Rákhely: Department of Biotechnology, University of Szeged, H-6726 Szeged, Hungary
Katalin Perei: Department of Biotechnology, University of Szeged, H-6726 Szeged, Hungary

IJERPH, 2020, vol. 17, issue 11, 1-17

Abstract: Used lubricant oils (ULOs) strongly bind to soil particles and cause persistent pollution. In this study, soil microcosm experiments were conducted to model the ex situ bioremediation of a long term ULO-polluted area. Biostimulation and various inoculation levels of bioaugmentation were applied to determine the efficacy of total petrol hydrocarbon (TPH) removal. ULO-contaminated soil microcosms were monitored for microbial respiration, colony-forming units (CFUs) and TPH bioconversion. Biostimulation with inorganic nutrients was responsible for 22% of ULO removal after 40 days. Bioaugmentation using two hydrocarbon-degrader strains: Rhodococcus quingshengii KAG C and Rhodococcus erythropolis PR4 at a small inoculum size (10 7 CFUs g −1 soil), reduced initial TPH concentration by 24% and 29%, respectively; the application of a higher inoculum size (10 9 CFUs g −1 soil) led to 41% and 32% bioconversion, respectively. After 20 days, all augmented CFUs decreased to the same level as measured in the biostimulated cases, substantiating the challenge for the newly introduced hydrocarbon-degrading strains to cope with environmental stressors. Our results not only highlight that an increased number of degrader cells does not always correlate with enhanced TPH bioconversion, but they also indicate that biostimulation might be an economical solution to promote ULO biodegradation in long term contaminated soils.

Keywords: soil rehabilitation; intensification; TPH biodegradation; used lubricants; inoculation level; Rhodococcus (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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