Isolation and characterisation of crude oil sludge degrading bacteria.

Linda U Obi,Rasheed A Adeleke,Harrison I Atagana

doi:10.1186/s40064-016-3617-z

Linda U Obi, Rasheed A Adeleke + Show 1 more

Open Access

https://doi.org/10.1186/s40064-016-3617-z

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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.

Highlights

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
One of the major limitations of polycyclic aromatic hydrocarbons (PAHs) biodegradation is the low bioavailability of pollutants to the degrading microorganisms
Isolation of bacteria After the enrichment cultivation, a total of 36 bacterial isolates were obtained from the compost samples and the control (Table 1)

Summary

Introduction

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. High demand for petroleum products all over the world has led to an increase in crude oil extraction and processing. This has resulted in an increased generation of large amounts of oily waste (Bhattacharyya and Shekdar 2003). The incorporation of commercially available surfactants in bioremediation techniques is a possible option for increasing the bioavailability of polycyclic aromatic hydrocarbons (PAHs) (Wong et al 2004; Wyrwas et al 2011)

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