Crude oil degradation efficiency of a recombinant Acinetobacter baumannii strain and its survival in crude oil-contaminated soil microcosm

Abstract

A hydrocarbon degrading Acinetobacter baumannii S30 strain, isolated from crude oil-contaminated soil, was inserted with the lux gene from the luciferase gene cassette luxCDABE. Soil microcosms were designed to study the degradation efficacy for total petroleum hydrocarbon (TPH) of crude oil by lux-tagged A. baumannii S30 pJES. Bioaugmentation of a TPH-contaminated microcosm with A baumannii S30 pJES showed that TPH levels were reduced from 89.3 to 53.9 g/kg soil in 90 days. Biodegradation of TPH by A baumannii S30 pJES was also monitored in shake flask conditions, which showed a reduction of initial TPH levels by over 50% at the end of 120 h. A lux-PCR-based approach along with the standard dilution plating with selective antibiotics was successfully utilized to monitor the survivability of the lux-tagged strain A. baumannii S30 pJES in soil microcosms and stability of the lux insert in the host strain A. baumannii S30. The selective plating technique indicated the population of A. baumannii S30 pJES to be 6.5+/-0.13 x 10(8) CFU/g at day zero (just after bioaugmentation) and 2.09+/-0.08 x 10(8) CFU/g of soil after 90 days of incubation. lux-PCR confirmed the stability of the insert in all the randomly selected colonies of A. baumannii strains from the antibiotic plates. The lux insert was stable after 50 generations in Luria Bertini broth and storage at -70 degrees C as glycerol stocks for over a year. These results revealed that the lux insert was stable and lux-tagged A. baumannii S30 strain could survive in a TPH-contaminated soil microcosm and could degrade TPH in the soil microcosm conditions. It can be used as an effective marker to monitor the survival of augmented strains at a bioremediation site.

Natural Attenuation of Oily Sludge Used for the Maintenance of an Unpaved Road in Arauca (Colombia)

“…The following bacteria were identified during the study: Pseudomonas aeruginosa (16%), Pseudomonas fluorescens (5%), Acinetobacter (5%), Stenotrophomonas maltophilia (5%), Ochrobactrum intermedium (5%), Stenotrophomonas acidaminiphila (11%), Microbacterium arborescens (5%), and Microbacterium barkeri (5%). All these bacteria have been previously reported as HC-degrading microorganisms (Röling et al, 2002;Saadoun, 2002;Margesin et al, 2003;Andreoni et al, 2004;Mishra et al, 2004;Moody et al, 2004;Dey and Roy, 2009;Owsianiak et al, 2009). Similar results were reported by Morelli et al (2005) who found that Pseudomonas and Acinetobacter were the predominant genera in hydrocarbon contaminated soils, and A. baumanii, has been reported to be a crude-degrader under laboratory conditions (Koren et al, 2003).…”

Degradation of pyrene by an enteric bacterium, Leclercia adecarboxylata PS4040

“…Oily sludge, a major petroleum refinery effluent, contains considerable amounts of PAH compounds (Seo et al 2009;Silva et al 2009). Accidental spillage and improper disposal of these materials have resulted in a number of contaminated sites presenting serious health and ecological risks (Mishra et al 2004;Tam and Wong 2008). Bioremediation technologies have increasingly been proposed to decontaminate these sites (Bhattacharya et al 2003;Silva et al 2009).…”

Response Surface Analysis to Improve Dispersed Crude Oil Biodegradation

“…The highest removal on un‐optimized condition of 68.1% were observed by using nitrogen of 20.00 mg/L and phosphorus 2.00 mg/L in 28 days while optimization process exhibited a crude oil removal of 69.5% via nitrogen of 16.05 mg/L and phosphorus 1.34 mg/L in 27 days, thus optimization can improve biodegradation in shorter time and with less nutrient consumption. The efficacy is more than other similar works; crude oil degradation of 42.9% in 28 days trial 32, 40% 33 and 40.5% 34 were reported before. Gentili et al 35 removed 60% of crude oil hydrocarbons from polluted seawater.…”