scholarly journals Bacterial community shift in nutrient-treated oil-bearing sandstones from the subsurface strata of an onshore oil reservoir and its potential use in Microbial Enhanced Oil Recovery

2018 ◽  
Author(s):  
Thanachai Phetcharat ◽  
Pinan Dawkrajai ◽  
Thararat Chitov ◽  
Pisanu Wongpornchai ◽  
Schradh Saenton ◽  
...  

AbstractMicrobial Enhanced Oil Recovery (MEOR) is a promising strategy to improve recovery of residual oil in reservoirs, which can be performed by promoting specific indigenous microorganisms. In this study, bacterial communities and the effects of elemental nutrient treatment of oil-bearing sandstone cores originated from six oil wells of an onshore reservoir was determined by tagged 16S rRNA gene amplicon sequencing, using Ion Torrent Metagenomic Sequencing Analysis. A total number of sequences were taxonomically classified into 43 phyla, 320 families, and 584 genera, with the dominant bacterial populations being related to Deinococcus-Thermus, and Betaproteobacteria. The nutrient treatment resulted in markedly increase in the relative abundance of Gammaproteobacteria. Thermus, Acinetobacter, and Pseudomonas were the most abundant genera. To our knowledge, this is the first report on the effect of elemental nutrients on alteration of bacteria communities attached to the oil-bearing rock. It provides comprehensive data on bacterial, physical, and chemical structures within a reservoir and demonstrates how these parameters can be co-analyzed to serve as a basis for designing a MEOR process. It also provides a model of how a bacterial community in reservoirs’ strata can be altered by nutrient treatment to enhance the efficiency of MEOR applications.

2020 ◽  
Vol 86 (14) ◽  
Author(s):  
Veronika Storck ◽  
Sara Gallego ◽  
Sotirios Vasileiadis ◽  
Sabir Hussain ◽  
Jérémie Béguet ◽  
...  

ABSTRACT Biobeds, designed to minimize pesticide point source contamination, rely mainly on biodegradation processes. We studied the interactions of a biobed microbial community with the herbicide isoproturon (IPU) to explore the role of the pdmA gene, encoding the large subunit of an N-demethylase responsible for the initial demethylation of IPU, via quantitative PCR (qPCR) and reverse transcription-PCR (RT-qPCR) and the effect of IPU on the diversity of the total bacterial community and its active fraction through amplicon sequencing of DNA and RNA, respectively. We further investigated the localization and dispersal mechanisms of pdmAB in the biobed packing material by measuring the abundance of the plasmid pSH (harboring pdmAB) of the IPU-degrading Sphingomonas sp. strain SH (previously isolated from the soil used in the biobed) compared with the abundance of the pdmA gene and metagenomic fosmid library screening. pdmA abundance and expression increased concomitantly with IPU mineralization, verifying its major role in IPU transformation in the biobed system. DNA- and RNA-based 16S rRNA gene sequencing analysis showed no effects on bacterial diversity. The pdmAB-harboring plasmid pSH showed a consistently lower abundance than pdmA, suggesting the localization of pdmAB in replicons other than pSH. Metagenomic analysis identified four pdmAB-carrying fosmids. In three of these fosmids, the pdmAB genes were organized in a well-conserved operon carried by sphingomonad plasmids with low synteny with pSH, while the fourth fosmid contained an incomplete pdmAB cassette localized in a genomic fragment of a Rhodanobacter strain. Further analysis suggested a potentially crucial role of IS6 and IS256 in the transposition and activation of the pdmAB operon. IMPORTANCE Our study provides novel insights into the interactions of IPU with the bacterial community of biobed systems, reinforces the assumption of a transposable nature of IPU-degrading genes, and verifies that on-farm biobed systems are hot spots for the evolution of pesticide catabolic traits.


Author(s):  
Jianlong Xiu ◽  
Tianyuan Wang ◽  
Ying Guo ◽  
Qingfeng Cui ◽  
Lixin Huang ◽  
...  

Microbiome ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Yusuke Okazaki ◽  
Shohei Fujinaga ◽  
Michaela M. Salcher ◽  
Cristiana Callieri ◽  
Atsushi Tanaka ◽  
...  

Abstract Background Freshwater ecosystems are inhabited by members of cosmopolitan bacterioplankton lineages despite the disconnected nature of these habitats. The lineages are delineated based on > 97% 16S rRNA gene sequence similarity, but their intra-lineage microdiversity and phylogeography, which are key to understanding the eco-evolutional processes behind their ubiquity, remain unresolved. Here, we applied long-read amplicon sequencing targeting nearly full-length 16S rRNA genes and the adjacent ribosomal internal transcribed spacer sequences to reveal the intra-lineage diversities of pelagic bacterioplankton assemblages in 11 deep freshwater lakes in Japan and Europe. Results Our single nucleotide-resolved analysis, which was validated using shotgun metagenomic sequencing, uncovered 7–101 amplicon sequence variants for each of the 11 predominant bacterial lineages and demonstrated sympatric, allopatric, and temporal microdiversities that could not be resolved through conventional approaches. Clusters of samples with similar intra-lineage population compositions were identified, which consistently supported genetic isolation between Japan and Europe. At a regional scale (up to hundreds of kilometers), dispersal between lakes was unlikely to be a limiting factor, and environmental factors or genetic drift were potential determinants of population composition. The extent of microdiversification varied among lineages, suggesting that highly diversified lineages (e.g., Iluma-A2 and acI-A1) achieve their ubiquity by containing a consortium of genotypes specific to each habitat, while less diversified lineages (e.g., CL500-11) may be ubiquitous due to a small number of widespread genotypes. The lowest extent of intra-lineage diversification was observed among the dominant hypolimnion-specific lineage (CL500-11), suggesting that their dispersal among lakes is not limited despite the hypolimnion being a more isolated habitat than the epilimnion. Conclusions Our novel approach complemented the limited resolution of short-read amplicon sequencing and limited sensitivity of the metagenome assembly-based approach, and highlighted the complex ecological processes underlying the ubiquity of freshwater bacterioplankton lineages. To fully exploit the performance of the method, its relatively low read throughput is the major bottleneck to be overcome in the future.


Author(s):  
Jéssica Correia ◽  
Lígia R. Rodrigues ◽  
José A. Teixeira ◽  
Eduardo J. Gudiña

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