scholarly journals Nitrate Reducing and Denitrifying Bacteria in Oil/Brine Contaminated Soils

2020 ◽  
pp. 699-705
Author(s):  
Samer AbuBakr

Soil microorganisms are a fundamental part of biogeochemical cycling of nitrogen. Denitrification is an important component of nitrogen cycling, in which some microorganisms (e.g. denitrifying bacteria) use nitrate or nitrite as alternative electron acceptors. In fact, several studies have focused on various aspects of nitrogen cycling. Philippot et al. (2009) linked the distribution of the fraction of bacteria with the genetic capacity to reduce N2O to N2 to areas with low potential N2O emissions in a pasture. In addition, it was shown that a map of denitrification activity across a whole farm was reflected by maps displaying the community size and structure of a specific fraction of the denitrifyers at the site (Enwall et al., 2010). Since denitrification releases mineralized nitrogen in the soil ecosystem to the atmosphere, the balance between denitrification and N-fixation can determine the biologically available nitrogen for soils. Denitrification could be affected by soil ecosystem contaminants such as crude oil and brine as they may alter the abundance and species composition of denitrifying bacteria in predictable ways. For example, γ-Proteobacteria are known to increase in crude-oil contaminated sites and in fact, a wide diversity of γ-Proteobacteria including Pseudomonas and Vibrio species were shown to degrade hydrocarbons under nitrate reducing (NR) conditions (Rockne et al., 2000). Other studies showed that strains for several genera of γ-Proteobacteria have the ability to denitrify. In fact, it was shown that nitrate and nitrite reduction rates were increasingly inhibited at increasing NaCl concentrations when comparing treatment of fishery wastewaters. Bacterial diversity in brine-contaminated sites is expected to be less because of selection for salt-tolerant genera such as Bacillus and Pseudomonas.

2022 ◽  
Vol 10 (1) ◽  
pp. 180
Author(s):  
Youwei Zuo ◽  
Huanhuan Qu ◽  
Changying Xia ◽  
Huan Zhang ◽  
Jiahui Zhang ◽  
...  

The uncontrolled invasion of moso bamboo (Phyllostachys pubescens) dramatically alters soil nitrogen cycling and destroys the natural habitat of Alsophila spinulosa. Nevertheless, no clear evidence points out the role of denitrifying bacteria in the invasion of bamboo into the habitat of A. spinulosa. In the present study, we found that low (importance value 0.0008), moderate (0.6551), and high (0.9326) bamboo invasions dramatically altered the underground root biomass of both P. pubescens and A. spinulosa. The root biomass of A. spinulosa was maximal at moderate invasion, indicating that intermediate disturbance might contribute to the growth and survival of the colonized plant. Successful bamboo invasion significantly increased rhizospheric soil available nitrogen content of A. spinulosa, coupled with elevated denitrifying bacterial abundance and diversity. Shewanella, Chitinophaga, and Achromobacter were the primary genera in the three invasions, whereas high bamboo invasion harbored more denitrifying bacteria and higher abundance than moderate and low invasions. Further correlation analysis found that most soil denitrifying bacteria were positively correlated with soil organic matter and available nitrogen but negatively correlated with pH and water content. In addition, our findings illustrated that two denitrifying bacteria, Chitinophaga and Sorangium, might be essential indicators for evaluating the effects of bamboo invasion on the growth of A. spinulosa. Collectively, this study found that moso bamboo invasion could change the nitrogen cycling of colonized habitats through alterations of denitrifying bacteria and provided valuable perspectives for profound recognizing the invasive impacts and mechanisms of bamboo expansion.


1990 ◽  
Vol 22 (6) ◽  
pp. 63-68 ◽  
Author(s):  
Philip Morgan ◽  
Robert J. Watkinson

Enhanced insitu biotreatment is a recent technology for the cleanup of contaminated soil and ground water but it has not yet been tested for many contaminants. This report describes the assessment of three hydrocarbon-contaminated sites, one contaminated with crude oil, one with lubricating oil and one with gasoline, with respect to their potential for biotreatment. All locations were permeable, sandy soils which contained low concentrations of extractable inorganic macronutrients. Degradative microbial populations were present, although their numbers were reduced in the most highly contaminated portions of the soil. Hydrocarbon analysis demonstrated that vertical penetration of contaminants into the soil was poor for the crude oil but had occurred at the other sites. There was some evidence that biodegradation at the crude and lubricating oil-contaminated sites may have occurred. The available data suggested that biotreatment of the lubricating and gasoline-contaminated sites by the provision of inorganic nutrients and oxygen to the soils might prove viable. However, it was found that the addition of inorganic nutrients resulted in an inhibition of mineralisation in the soils.


Genes ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 40
Author(s):  
Liang Cui ◽  
Bitong Zhu ◽  
Xiaobo Zhang ◽  
Zhuhua Chan ◽  
Chungui Zhao ◽  
...  

The elevated NH3-N and NO2-N pollution problems in mariculture have raised concerns because they pose threats to animal health and coastal and offshore environments. Supplement of Marichromatium gracile YL28 (YL28) into polluted shrimp rearing water and sediment significantly decreased ammonia and nitrite concentrations, showing that YL28 functioned as a novel safe marine probiotic in the shrimp culture industry. The diversity of aquatic bacteria in the shrimp mariculture ecosystems was studied by sequencing the V4 region of 16S rRNA genes, with respect to additions of YL28 at the low and high concentrations. It was revealed by 16S rRNA sequencing analysis that Proteobacteria, Planctomycete and Bacteroidetes dominated the community (>80% of operational taxonomic units (OTUs)). Up to 41.6% of the predominant bacterial members were placed in the classes Gammaproteobacteria (14%), Deltaproteobacteria (14%), Planctomycetacia (8%) and Alphaproteobacteria (5.6%) while 40% of OTUs belonged to unclassified ones or others, indicating that the considerable bacterial populations were novel in our shrimp mariculture. Bacterial communities were similar between YL28 supplements and control groups (without addition of YL28) revealed by the β-diversity using PCoA, demonstrating that the additions of YL28 did not disturb the microbiota in shrimp mariculture ecosystems. Instead, the addition of YL28 increased the relative abundance of ammonia-oxidizing and denitrifying bacteria. The quantitative PCR analysis further showed that key genes including nifH and amoA involved in nitrification and nitrate or nitrite reduction significantly increased with YL28 supplementation (p < 0.05). The supplement of YL28 decreased the relative abundance of potential pathogen Vibrio. Together, our studies showed that supplement of YL28 improved the water quality by increasing the relative abundance of ammonia-oxidizing and denitrifying bacteria while the microbial community structure persisted in shrimp mariculture ecosystems.


Soil Research ◽  
1992 ◽  
Vol 30 (6) ◽  
pp. 937 ◽  
Author(s):  
KG Tiller

The current knowledge of the pollution of Australian urban soils was reviewed with special reference to heavy metals. Increased community concern in recent years has resulted m a major upsurge in the investigation and rehabilitation of contaminated soils. This has led to a concomitant reassessment and development of regulatory procedures, and the establishment of some new environmental agencies. This review considers sources and extent of contamination, and approaches to the establishment of reference background levels in urban and rural areas. Assessment of contaminated sites has been largely based on overseas experience but site specific approaches relevant to Australian soils and climates are needed and are being developed by State authorities in collaboration with the Australian and New Zealand Environmental and Conservation Council and the National Health and Medical Research Council. The need for soil-based research and for standardized soil sampling procedures for site evaluation and action is stressed. Many opportunities exist for soil scientists in solving problems of soil contamination and rehabilitation.


2017 ◽  
Vol 9 (8) ◽  
pp. 1365 ◽  
Author(s):  
Diana Cocârţă ◽  
Mihaela Stoian ◽  
Aykan Karademir

2016 ◽  
Vol 167 (9-10) ◽  
pp. 731-744 ◽  
Author(s):  
Xinzi Wang ◽  
Xiaohui Zhao ◽  
Hanbing Li ◽  
Jianli Jia ◽  
Yueqiao Liu ◽  
...  

2019 ◽  
Vol 37 ◽  
Author(s):  
M.J. KHAN ◽  
N. AHMED ◽  
W. HASSAN ◽  
T. SABA ◽  
S. KHAN ◽  
...  

ABSTRACT: Phytoremediation is a useful tool to restore heavy metals contaminated soils. This study was carried out to test two castor (Ricinus communis) cultivars [Local and DS-30] for phytoextraction of heavy metals from the soil spiked by known concentrations of seven metals (Cu, Cr, Fe, Mn, Ni, Pb and Zn). A pot experiment was laid out by using a completely randomized design. Soil and plant samples were analyzed at 100 days after planting. The data on heavy metal uptake by plant tissues (roots, leaves and shoots) of the two castor cultivars suggested that a considerable amount of metals (Fe = 27.18 mg L-1; Cu = 5.06 mg L-1; Cr = 2.95 mg L-1; Mn = 0.22 mg L-1; Ni = 4.66 mg L-1; Pb = 3.33 mg L-1; Zn = 15.04 mg L-1) was accumulated in the plant biomass. The soil heavy metal content at the end of experiment significantly decreased with both cultivars, resulting in improved soil quality. Therefore, it is concluded that both castor cultivars, Local and DS-30, can be used for phytoremediation of heavy metal-contaminated sites.


Author(s):  
Tudararo-Aherobo Laurelta ◽  
Okotie Sylvester ◽  
Ataikiru Tega ◽  
Stephen Avwerosuoghene

Aim: The research aims to assess the biodegradability of crude oil polluted aquatic environment using indigenous hydrocarbon degrading bacteria. Place and Duration of Study: The research was conducted in the Environmental Management and Toxicology Laboratory, Federal University of Petroleum Resources, Effurun, Delta State. Methodology: Hydrocarbon degrading bacteria species were isolated from hydrocarbon contaminated soils, screened and used for the degradation of crude oil. 5% and 10% crude oil were used to spike the test microcosm. Physicochemical parameters such as, pH, turbidity, total petroleum hydrocarbon (TPH) and bacterial counts of the bioremediated crude oil contaminated water were monitored on Day 0, 7 and 14. The biodegradation of the crude oil was done with the various bacteria isolates singly and as a consortium. Standard methods of American Public Health Association (APHA) and American Society for Testing and Materials (ASTM) were used for the analysis. Results: The isolates identified and used for the biodegradation process were, Azomonas sp., Enterococcus sp., Klebsiella sp. and Rhizobactersp. On day 14, in the microcosms with 5% crude oil contamination, Azomonas sp. recorded the highest turbidity reading of 328 ± 2.0 NTU, while Rhizobacter sp. recorded the least with 57.67 ± 0.58 NTU. The bacterial countswere between 7.68 ± 0.002 CFU/ml and 8.05 ± 0.10x 107 CFU/ml for Rhizobacter sp. and Azomonas sp. respectively.The crude oil was also degraded most in the microcosm treated with Azomonas sp. with a residual TPH concentration of 0.0013± 0.005 mg/l.For the 10% crude oil contaminated microcosms, TPH was also biodegraded most by Azomonas sp. with a value of 0.0026 ± 0.002mg/l. Turbidity readings were between 82 ± 1.0 NTU and 375.33 ± 0.57 NTU for Rhizobacter sp. and Azomonas sp. respectively. Bacterial counts were between (7.71± 0.012)x 107CFU/ml – (8.13± 0.001) x 107CFU/ml for Rhizobacter sp. and Azomonassp. respectively. Conclusion:There wasincreased microbial countsand decrease of residual crude oil concentration, indicating degradation of the crude oil by all the isolates.However, Azomonas sp. recorded the highest TPH degradation for both the 5% and 10% crude oil contaminated microcosms.Thus, findings from the research indicate that hydrocarbon degrading bacteria exist in our environment and can be used in the remediation of aquatic polluted environment.


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