Screening of biosurfactant-producing bacteria from offshore oil and gas platforms in North Atlantic Canada

Abstract

From offshore oil and gas platforms in North Atlantic Canada, crude oil, formation water, drilling mud, treated produced water and seawater samples were collected for screening potential biosurfactant producers. In total, 59 biosurfactant producers belong to 4 genera, namely, Bacillus, Rhodococcus, Halomonas, and Pseudomonas were identified and characterized. Phytogenetic trees based on 16S ribosomal deoxyribonucleic acid (16S rDNA) were constructed with isolated strains plus their closely related strains and isolated strains with biosurfactant producers in the literature, respectively. The distributions of the isolates were site and medium specific. The richness, diversity, and evenness of biosurfactant producer communities in oil and gas platform samples have been analyzed. Diverse isolates were found with featured properties such as effective reduction of surface tension, producing biosurfactants at high rate and stabilization of water-in-oil or oil-in-water emulsion. The producers and their corresponding biosurfactants had promising potential in applications such as offshore oil spill control, enhancing oil recovery and soil washing treatment of petroleum hydrocarbon-contaminated sites.

A novel bioemulsifier produced by Exiguobacterium sp. strain N4-1P isolated from petroleum hydrocarbon contaminated coastal sediment

“…The surface tension and emulsication index (E24) of the culture broth were tested. 4 The clear broths were concentrated to approximately 1/5 of the volume with lyophilisation, and then were mixed with three volumes of cold acetone. Subsequently, the solution was stored at 4 C for 3 days to fully precipitate the crude bioemulsier products.…”

“…The bioemulsier solutions were mixed with equal amount of diesel and vortexed for 2 min. Aer settling for 24 hours, E24 was determined by the fraction height of the emulsion layer out of the total height of the mixture (Cai et al, 2015). The emulsication abilities of the bioemulsier solution, against different hydrocarbons including hexadecane, mineral oil, crude oil, diesel, xylene, toluene, dodecane, and iso-octane were tested.…”

“…serving as soil washing and bioremediation enhancement agents. [4][5][6] However, chemically synthesized emulsiers suffer from toxicity concerns and have hazardous environmental impacts.…”

Isolation of nitrate-reducing bacteria from an offshore reservoir and the associated biosurfactant production

“…Cai et al 30 isolated marine biosurfactant producers from crude oil, formation water, drilling mud, and treated produced water samples in offshore oil and gas elds. The genotype and phylogenetic relation of these isolates were investigated and biosurfactant producers were primarily found in the genera of Rhodococcus and Halomonas.…”

“…The two surfactant production media with glycerol and glucose as carbon sources were used to investigate the performance of biosurfactant production. The incubation was conducted at 30 C while shaking at 200 rpm.…”