Genomovar assignment of Pseudomonas stutzeri populations inhabiting produced oil reservoirs.

Fan Zhang,Ibrahim M Banat,Shao‐Jin Yi,Zheng‐Liang Wang,Du‐Jie Hou,Yue‐Hui She,Liu‐Qin Huang,Lu‐Jun Chai,Hai‐Liang Dong

doi:10.1002/mbo3.179

Abstract

Oil reservoirs are specific habitats for the survival and growth of microorganisms in general. Pseudomonas stutzeri which is believed to be an exogenous organism inoculated into oil reservoirs during the process of oil production was detected frequently in samples from oil reservoirs. Very little is known, however, about the distribution and genetic structure of P. stutzeri in the special environment of oil reservoirs. In this study, we collected 59 P. stutzeri 16S rRNA gene sequences that were identified in 42 samples from 25 different oil reservoirs and we isolated 11 cultured strains from two representative oil reservoirs aiming to analyze the diversity and genomovar assignment of the species in oil reservoirs. High diversity of P. stutzeri was observed, which was exemplified in the detection of sequences assigned to four known genomovars 1, 2, 3, 20 and eight unknown genomic groups of P. stutzeri. The frequent detection and predominance of strains belonging to genomovar 1 in most of the oil reservoirs under study indicated an association of genomovars of P. stutzeri with the oil field environments.

Highlights

Pseudomonas stutzeri is a nonfluorescent widely distributed species of the genus Pseudomonas belonging to the gamma subclass of Proteobacteria (Bennasar et al 1996; Lalucat et al 2006)
These sequences affiliated to P. stutzeri were reported/detected in samples collected from production wellheads, injection wells, crude oils, and cores of oil reservoirs in Malaysia (Li et al 2012), Alaska (Pham et al 2009), Brazil (Silva et al 2013), Middle East (Yamane et al 2008), Japan (Nunoura et al 2006; Yamane et al 2008) and China (Li et al 2007; Ren et al 2011; Tang et al.2012; Zhang et al 2012; Zhao et al 2012)
These reservoirs had an in situ temperature range of 25–80°C, depth range of 535.5–2800 m, pH of produced fluids range of 6.7–9.2, and a ClÀ range concentration of 502–150513 mg/L. Most of these oil reservoirs have been subjected to water-flooding for decades to enhance oil recovery with the fraction of water being coproduced with oil ranging from 70% to 97%

Summary

Introduction

Pseudomonas stutzeri is a nonfluorescent widely distributed species of the genus Pseudomonas belonging to the gamma subclass of Proteobacteria (Bennasar et al 1996; Lalucat et al 2006). The species has great physiological capacities including the ability to degrade environmental pollutants such as high-molecular-weight polyethylene glycols and other xenobiotics (Criddle et al 1990; Chauhan et al 1998; Coates et al 1999) and the cleavage of C–N bonds in oil compounds (Kilbane et al 2003). It has been considered of relevance as a possible environmental reservoir of antibiotic resistance genes (Garcıa-Valdes et al 2010) and in applications related to microbial enhanced oil recovery (EOR) (Keeler et al 2013).

Objectives

Results

Conclusion