scholarly journals Ecological Response in the Integrated Process of Biostimulation and Bioaugmentation of Diesel-Contaminated Soil

2021 ◽  
Vol 11 (14) ◽  
pp. 6305
Author(s):  
Xiaosen Li ◽  
Yakui Chen ◽  
Xianyuan Du ◽  
Jin Zheng ◽  
Diannan Lu ◽  
...  
Keyword(s):  
Nitrogen Cycle ◽  
Contaminated Soil ◽  
Quantitative Polymerase Chain Reaction ◽  
Chemical Properties ◽  
Gas Chromatography Mass Spectrometry ◽  
Functional Genes ◽  
Alkane Degradation ◽  
Degrading Bacteria ◽  
Polycyclic Aromatic ◽  
Amine Compounds

The study applied microbial molecular biological techniques to show that 2.5% to 3.0% (w/w) of diesel in the soil reduced the types and number of bacteria in the soil and destroyed the microbial communities responsible for the nitrogen cycle. In the meantime, the alkane degradation gene alkB and polycyclic aromatic hydrocarbons (PAHs) degradation gene nah evolved in the contaminated soil. We evaluated four different remediation procedures, in which the biostimulation-bioaugmentation joint process reached the highest degradation rate of diesel, 59.6 ± 0.25% in 27 days. Miseq sequencing and quantitative polymerase chain reaction (qPCR) showed that compared with uncontaminated soil, repaired soil provides abundant functional genes related to soil nitrogen cycle, and the most significant lifting effect on diesel degrading bacteria γ-proteobacteria. Quantitative analysis of degrading functional genes shows that degrading bacteria can be colonized in the soil. Gas chromatography-mass spectrometry (GC-MS) results show that the components remaining in the soil after diesel degradation are alcohol, lipids and a small amount of fatty amine compounds, which have very low toxicity to plants. In an on-site remediation experiment, the diesel content decreased from 2.7% ± 0.3 to 1.12% ± 0.1 after one month of treatment. The soil physical and chemical properties returned to normal levels, confirming the practicability of the biosimulation-bioaugmentation jointed remediation process.

scholarly journals Isolation and Characterization of a Bacterial Strain Enterobacter cloacae (Accession No. KX438060.1) Capable of Degrading DDTs Under Aerobic Conditions and Its Use in Bioremediation of Contaminated Soil

2021 ◽  
Vol 14 ◽  
pp. 117863612110242
Author(s):  
Sonal Suman ◽  
Tanuja
Keyword(s):  
Contaminated Soil ◽  
Growth Parameters ◽  
Chemical Properties ◽  
Enterobacter Cloacae ◽  
Maximum Growth ◽  
Bacterial Degradation ◽  
Biochemical Tests ◽  
Isolation And Characterization ◽  
16S Rna ◽  
Degrading Bacteria

DDT is one of the most persistent pesticides among all the different types of organo-chlorine pesticides used. Among all the degradation methods, bacterial degradation of DDT is most effective. The present study was conducted to isolate different bacteria present in waste samples which have the ability to degrade DDT present in the soil in the minimum possible period of time and to observe the effect of different physical and chemical properties of the soil samples. Many pesticide degrading bacteria were isolated and identified through cultural, biochemical tests and further identified by 16S RNA sequencing method. The most potent strain DDT 1 growth in mineral salt medium supplemented with DDT as the only source of carbon (5-100 PPM) and was monitored at an optical density of 600 nm. The growth parameters at different physio-chemical conditions were further optimized. The result showed that Enterobacter cloacae had maximum growth in 15 days. FTIR analysis of the residual DDT after 15 days incubation showed that Enterobacter cloacae was able to degrade pesticide into its further metabolites of DDD, DDE, DDNU and other components can be used for biodegradation of DDT present in contaminated soil and water ecosystems.

scholarly journals The Polycyclic Aromatic Hydrocarbon (PAH) degradation activities and genome analysis of a novel strain Stenotrophomonas sp. Pemsol isolated from Mexico

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8102
Author(s):  
Temidayo O. Elufisan ◽  
Isabel C. Rodríguez-Luna ◽  
Omotayo Opemipo Oyedara ◽  
Alejandro Sánchez-Varela ◽  
Armando Hernández-Mendoza ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Crude Oil ◽  
Contaminated Soil ◽  
Antimicrobial Agents ◽  
Carbon Sources ◽  
Genomic Islands ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Wide Range ◽  
Polycyclic Aromatic

Background Stenotrophomonas are ubiquitous gram-negative bacteria, which can survive in a wide range of environments. They can use many substances for their growth and are known to be intrinsically resistant to many antimicrobial agents. They have been tested for biotechnological applications, bioremediation, and production of antimicrobial agents. Method Stenotrophomonas sp. Pemsol was isolated from a crude oil contaminated soil. The capability of this isolate to tolerate and degrade polycyclic aromatic hydrocarbons (PAH) such as anthraquinone, biphenyl, naphthalene, phenanthrene, phenanthridine, and xylene was evaluated in Bushnell Hass medium containing PAHs as the sole carbon sources. The metabolites formed after 30-day degradation of naphthalene by Pemsol were analyzed using Fourier Transform Infra-red Spectroscopic (FTIR), Ultra-Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS) and Gas Chromatography-Mass Spectrometry (GC-MS). The genome of Pemsol was also sequenced and analyzed. Results Anthraquinone, biphenyl, naphthalene, phenanthrene, and phenanthridine except xylene can be used as sole carbon sources for Pemsol’s growth in Bushnell Hass medium. The degradation of naphthalene at a concentration of 1 mg/mL within 30 days was tested. A newly formed catechol peak and the disappearance of naphthalene peak detected on the UPLC-MS, and GC-MS analyses spectra respectively confirmed the complete degradation of naphthalene. Pemsol does not produce biosurfactant and neither bio-emulsify PAHs. The whole genome was sequenced and assembled into one scaffold with a length of 4,373,402 bp. A total of 145 genes involved in the degradation of PAHs were found in its genome, some of which are Pemsol-specific as compared with other 11 Stenotrophomonas genomes. Most specific genes are located on the genomic islands. Stenotrophomonas sp. Pemsol’s possession of few genes that are associated with bio-emulsification gives the genetic basis for its inability to bio-emulsify PAH. A possible degradation pathway for naphthalene in Pemsol was proposed following the analysis of Pemsol’s genome. ANI and GGDH analysis indicated that Pemsol is likely a new species of Stenotrophomonas. It is the first report on a complete genome sequence analysis of a PAH-degrading Stenotrophomonas. Stenotrophomonas sp. Pemsol possesses features that make it a good bacterium for genetic engineering and will be an excellent tool for the remediation of crude oil or PAH-contaminated soil.

scholarly journals Evaluation of Inoculum Addition To Stimulate In Situ Bioremediation of Oily-Sludge-Contaminated Soil

2001 ◽  
Vol 67 (4) ◽  
pp. 1675-1681 ◽  
Author(s):  
Sanjeet Mishra ◽  
Jeevan Jyot ◽  
Ramesh C. Kuhad ◽  
Banwari Lal
Keyword(s):  
Feasibility Study ◽  
Contaminated Soil ◽  
Chemical Properties ◽  
Bacterial Consortium ◽  
Full Scale ◽  
Oil Refinery ◽  
Oily Sludge ◽  
In Situ Bioremediation ◽  
Degrading Bacteria

ABSTRACT A full-scale study evaluating an inoculum addition to stimulate in situ bioremediation of oily-sludge-contaminated soil was conducted at an oil refinery where the indigenous population of hydrocarbon-degrading bacteria in the soil was very low (103 to 104 CFU/g of soil). A feasibility study was conducted prior to the full-scale bioremediation study. In this feasibility study, out of six treatments, the application of a bacterial consortium and nutrients resulted in maximum biodegradation of total petroleum hydrocarbon (TPH) in 120 days. Therefore, this treatment was selected for the full-scale study. In the full-scale study, plots A and B were treated with a bacterial consortium and nutrients, which resulted in 92.0 and 89.7% removal of TPH, respectively, in 1 year, compared to 14.0% removal of TPH in the control plot C. In plot A, the alkane fraction of TPH was reduced by 94.2%, the aromatic fraction of TPH was reduced by 91.9%, and NSO (nitrogen-, sulfur-, and oxygen-containing compound) and asphaltene fractions of TPH were reduced by 85.2% in 1 year. Similarly, in plot B the degradation of alkane, aromatic, and NSO plus asphaltene fractions of TPH was 95.1, 94.8, and 63.5%, respectively, in 345 days. However, in plot C, removal of alkane (17.3%), aromatic (12.9%), and NSO plus asphaltene (5.8%) fractions was much less. The population of introduced Acinetobacter baumannii strains in plots A and B was stable even after 1 year. Physical and chemical properties of the soil at the bioremediation site improved significantly in 1 year.

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