Isolation of Indigenous Hydrocarbon Transforming Bacteria from Oil Contaminated Soils in Libya: Selection for Use as Potential Inocula for Soil Bioremediation

The Libyan oil industry has left a significant legacy of contamination and methods are required to remediate oil-contaminated soils in the area. In this work hydrocarbon utilizing microorganisms were isolated and identified from contaminated soil samples obtained from an oil Refinery (Zawia, Libya). After initial screening of eleven isolates capable of growth on hexadecane, the five most promising hydrocarbon–utilizing bacteria were isolated and tested for biosurfactant production and emulsification activity. They were identified (using 16S rRNA sequence analysis) as Pseudomonas putida, Pseudomonas species, Betaproteobacterium, Actinomyces species, and Bacillus species. Among the five species tested, Pseudomonas putida showed superior performance in terms of growth on hydrocarbons (1.0×10 10 CFU (ml)), E24 emulsifying activity (86%) and ability to transform hydrocarbons in pure culture. Interestingly, gas chromatographic analysis of crude oil treated with P. putida showed a decrease in heavy hydrocarbon fractions demonstrating a clear potential for this microbe to be used as a soil inoculant in bioremediation

A Novel Approach to Enhance Crude Oil Recovery Ratio Using Selected Bacterial Species

The high viscosity and low flow properties of some crude oil make them difficult to extract from oil reservoirs. This study investigated the mechanisms responsible for the enhancement of oil recovery using fractured dolomite core models. Bacterial strains, Nocardia cyriacigeorgica, Bacillus species, and Pseudomonasputida, isolated from Libyan oil fields, had the ability to biotransform heavy crude oil by reducing its viscosity and converting heavier components into lighter ones. The efficiencies of the three bacterial strains were assessed using sand-packed column experiments through the injection of bacteria to mimic in-situ oil recovery. The optimum biotransformation values of Libyan Bouri crude oil were determined as 77.1, 61.2, and 61.1% using the Bacillus sp., P. putida, and Nocardia cyriacigeorgica, respectively, at 55 °C. Viscosity analyses showed that these strains resulted in the reduction of the viscosity of the crude oil at two different temperatures of 37 and 55 °C. The highest recovery of residual oil was about 11.3% using Bacillus sp. The study confirmed that the selected bacterial species were capable of displacing additional oil under simulated oil field conditions

Laboratory and pilot-scale studies on the bioremediation of oil contaminated soil

Petroleum contamination of sandy soils is a severe environmental problem in Libya but relatively little work has been carried out to optimize the bioremediation of such soils. The purpose of this thesis was to determine the potential for bioremediation 0 hydrocarbon-contaminated soil obtained from the Zawia refinery field, Libya. Initial work involved chemical and microbial characterisation of the contaminated soil. Chemical analysis revealed high levels of petroleum contamination (up to 26532 mg TPH per kg soil) and that the soil was contaminated with a mixture of crude oil an, diesel oil. Five isolates from the contaminated soil were identified as potential hydrocarbon degraders and were able to grow on crude oil and diesel oil as a sole carbon source, Two isolates, Pseudomonas putida and Bacillus sp., were chosen for us as potential microbial inoculants because they showed superior pertormance in terms growth on hydrocarbons, emulsifying activity and ability to transform hydrocarbons in pure culture.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Correction: Althalb et al. A Novel Approach to Enhance Crude Oil Recovery Ratio Using Selected Bacterial Species. Appl. Sci. 2021, 11, 10492

In the original publication [...