Enhanced haloarchaeal oil removal in hypersaline environments via organic nitrogen fertilization and illumination

• Published in: Extremophiles : life under extreme conditions 2012-09, Vol.16 (5), p.751-758
• Main Authors: Al-Mailem, D. M., Eliyas, M., Radwan, S. S.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Antibiotics; Archaea - growth & development; Archaea - metabolism; Bacteria; Bacteriology; Biochemistry; Biodegradation, Environmental; Biological and medical sciences; Biomedical and Life Sciences; Bioremediation; Biotechnology; Crude oil; Exiguobacterium; Fundamental and applied biological sciences. Psychology; Haloferax; Halomonas; Halomonas aquamarina; Incubation; Life Sciences; Microbial Ecology; Microbiology; Microorganisms; Moisture content; Nitrogen - metabolism; Oil removal; Organic fertilizers; Organic nitrogen; Original Paper; Petroleum - metabolism; Petroleum - microbiology; Petroleum Pollution; Ponds; Salinity; Soil Microbiology; Soil water; Water analysis; Water Microbiology; Water sampling
• ISSN: 1431-0651; 1433-4909
• DOI: 10.1007/s00792-012-0471-y

Hypersaline soil and pond water samples were mixed with 3 % crude oil, some samples were autoclaved to serve as sterile controls; experimental samples were not sterilized. After 6-week incubation at 40 °C under light/dark cycles, the soil microflora consumed 66 %, and after 4 weeks the pond water microflora consumed 63 % of the crude oil. Soil samples treated with 3 % casaminoacids lost 89 % of their oil after 6 weeks and water samples lost 86 % after 4 weeks. Samples treated with casaminoacids and antibiotics that selectively inhibited bacteria, lost even more oil, up to 94 %. Soil–water mixtures incubated under continuous illumination lost double as much more oil than samples incubated in the dark. The soil–water mixture at time zero contained 1.3 × 10 4 CFU g −1 of hydrocarbon-utilizing microorganisms which were affiliated to Halomonas aquamarina, Exiguobacterium aurantiacum , Haloferax sp., Salinococcus sp., Marinococcus sp. and Halomonas sp. After 6-week incubation with oil, these numbers were 8.7 × 10 7  CFU g −1 and the Haloferax sp. proportion in the total microflora increased from 20 to 93 %. Experiments using the individual cultures and three other haloarchaea isolated earlier from the same site confirmed that casaminoacids and light enhanced their oil consumption potential in batch cultures.