Bioremediation of oil-based drill cuttings by a halophilic consortium isolated from oil-contaminated saline soil

• Published in: 3 Biotech Vol. 8; no. 5; pp. 229 - 13
• Main Authors: Rezaei Somee, Maryam, Shavandi, Mahmoud, Dastgheib, Seyed Mohammad Mehdi, Amoozegar, Mohammad Ali
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-05-2018; Springer Nature B.V
• Subjects: Agriculture; Arthrobacter; Bacteria; Biodegradation; Bioinformatics; Biological activity; Biomaterials; Bioremediation; Biotechnology; Cancer Research; Chemistry; Chemistry and Materials Science; Chips; Communities; Consortia; Coordination compounds; Degradation; Diesel fuels; Dilution; Electrophoresis; Gel electrophoresis; Hazardous wastes; Heavy metals; Hydrocarbons; Microcosms; Microorganisms; Oil; Original; Original Article; Remediation; rRNA 16S; Saline soils; Saline water; Sand; Soil contamination; Soil dynamics; Soil pollution; Stem Cells; Halophilic consortium; Bioremediation; DGGE; Drilling fluids; Drill cuttings
• ISSN: 2190-572X; 2190-5738
• DOI: 10.1007/s13205-018-1261-8

Oil-based drill cuttings are hazardous wastes containing complex hydrocarbons, heavy metals, and brine. Their remediation is a crucial step before release to the environment. In this work, we enriched a halophilic consortium, from oil-polluted saline soil, which is capable of degrading diesel as the main pollutant of oil-based drill cuttings. The degradation ability of the consortium was evaluated in microcosms using two different diluting agents (fine sand and biologically active soil). During the bioremediation process, the bacterial community dynamics of the microcosms was surveyed using PCR amplification of a fragment of 16S rRNA gene followed by denaturing gradient gel electrophoresis (DGGE). The diesel degradation rates were monitored by total petroleum hydrocarbon (TPH) measurement and the total count of heterotrophic and diesel-degrading bacteria. After 3 months, the microcosm containing fine sand and drill cuttings with the ratio of 1:1 (initial TPH of 36,000 mg/kg) showed the highest TPH removal (40%) and its dominant bacterial isolates belonged to the genera
Dietzia, Arthrobacter
, and
Halomonas
. DGGE results also confirmed the role of these genera in drill cuttings remediation. DGGE analysis of the bacterial diversity showed that
Propionibacterium, Salinimicrobium, Marinobacter
, and
Dietzia
are dominant in active soil microcosm; whereas
Bacillus, Salinibacillus
, and
Marinobacter
are abundant in sand microcosm. Our results suggest that the bioaugmentation strategy would be more successful if the diluting agent does not contain a complex microbial community.