Isolation and characterisation of crude oil sludge degrading bacteria

Abstract

Background The use of microorganisms in remediating environmental contaminants such as crude oil sludge has become a promising technique owing to its economy and the fact it is environmentally friendly. Polycyclic aromatic hydrocarbons (PAHs), as the major components of oil sludge, are hydrophobic and recalcitrant. An important way of enhancing the rate of PAH desorption is to compost crude oil sludge by incorporating commercial surfactants, thereby making them available for microbial degradation. In this study, crude oil sludge was composted for 16 weeks during which surfactants were added in the form of a solution.ResultsMolecular characterisation of the 16S rRNA genes indicated that the isolates obtained on a mineral salts medium belonged to different genera, including Stenotrophmonas, Pseudomonas, Bordetella, Brucella, Bacillus, Achromobacter, Ochrobactrum, Advenella, Mycobacterium, Mesorhizobium, Klebsiella, Pusillimonas and Raoultella. The percentage degradation rates of these isolates were estimated by measuring the absorbance of the 2,6-dichlorophenol indophenol medium. Pseudomonas emerged as the top degrader with an estimated percentage degradation rate of 73.7% after 7 days of incubation at 28 °C. In addition, the presence of the catabolic gene, catechol-2,3-dioxygenase was detected in the bacteria isolates as well as in evolutionary classifications based on phylogeny.ConclusionsThe bacteria isolated in this study are potential agents for the bioremediation of crude oil sludge.

Potential microbial drivers of biodegradation of polycyclic aromatic hydrocarbons in crude oil sludge using a composting technique

“…The enrichment culture technique also produced 36 bacterial isolates that possibly utilized crude oil sludge for their energy and carbon requirements, as crude oil sludge was the sole carbon source during the enrichment. The results of the identification and characterization of bacterial isolates have been published previously . A total of 17 PAHs were quantitatively identified in the crude oil sludge used in this study, 15 of which are in the US EPA list of priority pollutants (Table ).…”

“…Several subculturing exercises resulted in the generation of pure colonies, which were stored in nutrient agar slants for further classification. Colony PCR was used to amplify the 16S rRNA region of the DNA of bacterial cells . This is the use of colonies from agar plates as DNA template for PCR.…”

“…This method lyses the bacterial cell thereby releasing the DNA from the cell into the sterile distilled water in the 2 mL tube. The method described in section 2.3 was used to prepare the amplification reaction as well as cycling conditions but the annealing temperature was set at 53 °C using the universal 16S rRNA bacterial primers, 27F (5′‐ AGA GTT TGA TCC TGG CTC AG ‐3′) and 1492R (5′‐ CGG CTA CCT TGT TAC GAC TT ‐3′) (synthesized by Inqaba biotechnological Industries PTY Ltd, Pretoria, South Africa) …”

Petroleum Degradation: Promising Biotechnological Tools for Bioremediation

“…In a more recent laboratory-based study, Pseudomonas sp. has removed 74% of PHs from the crude oil sludge in 7 days [30].…”

Community composition and functions of endophytic bacteria of Bt maize

“…DNA amplification of the isolates was done directly using the suspended cells in a colony polymerase chain reaction (PCR). 21,22 The PCR targeted the partial 16S rDNA gene of the bacterial isolates. The amplification was done using primer sets 341F (5' CCTACGGGAGGCACCAG3') and 907R (5' CCGTCAATTCCTTTGATTT3').…”