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

Abstract

a Biosurfactant producing nitrate-reducing bacteria (NRB) in anaerobic reservoir environments are closely associated with souring (H 2 S) control in the offshore oil and gas industry. Five NRB strains were screened from offshore produced water samples and all were identified as Pseudomonas stutzeri. Their biosurfactant producing abilities when fed on either glucose or glycerol media were investigated. P. stutzeri CX3 reduced the medium surface tension to 33.5 and 29.6 mN m À1, respectively, while growing on glucose or glycerol media. The CX3 strain was further inoculated to examine its growth performance, resulting in 32.4% and 94.5% of nitrate consumption over 228 hours of monitoring in two media, respectively. The composition analysis of the biosurfactant product generated by P. stutzeri CX3 was conducted through thin-layer chromatography, gas chromatography with a flame ionization detector

Prospects of Microbial Bio‐surfactants To Endorse Prolonged Conservation in the Pharmaceutical and Agriculture Industries

“…In both laboratory and large‐scale industrial fermenters, the type and amount of C and N present in the medium, as well as their ratio, directly impact microbial growth and biosurfactant production. In most experiments, glycerol, sucrose, and glucose are employed as C and yeast extract as N sources [47,48] . Furthermore, soya broth, urea, and NaNO 3 have been documented as N sources in the culture medium [49,50] .…”

“…In most experiments, glycerol, sucrose, and glucose are employed as C and yeast extract as N sources. [47,48] Furthermore, soya broth, urea, and NaNO 3 have been documented as N sources in the culture medium. [49,50] However, for optimal biosurfactant formation, conditions in which C sources are abundant while nitrogen is limited are recommended.…”

Impact of Bio-Competitive Exclusion on Nitrate-Reducing Bacteria in Oil Reservoir Water Treatment

“…There was a low concentration of toluene and other alkylbenzenes in the oil that was extracted from these wells, suggesting that they were not suitable substrates for hNRB. Alkylbenzeneoxidizing bacteria, such as Thauera and Azoarcus, have been shown to form part of the bacterial community in MHGCs [14]. Nitrate reduction seems to be impeded by the presence of any alkylbenzenes, however minute.…”

Nutrient Stimulation of Indigenous Microorganisms for Oil-in-Water Emulsion in a Medium Temperature Petroleum Reservoir with Ca2+-Rich Brine

“…IMEOR is a multidiscipline process that increases oil recovery through stimulation of microorganisms in a reservoir with an injection of specific nutrients for artificially directing metabolic activities to exert functions such as the degradation of heavy friction of crude oil, the formation of stable oil-water emulsions, low interfacial tension, increment of inner pressure, change of wettability, and redirection of injection fluids through clogging high permeable zones [3,4]. Among these beneficial effects, the formation of stable oil-in-water (o/w) emulsion by biosurfactant has been well acknowledged with extensive evidences from worldwide laboratories and oilfield trials [5,6]. Therefore, numerous literatures have reported the biosurfactant and its related producer from ex situ and indigenous environment [7][8][9].…”