scholarly journals Enhanced rhizodegradation of polycyclic aromatic hydrocarbons in corn straw-amended soil related to changing of bacterial community and functional gene expression

2021 ◽  
Author(s):  
Huanyu Bao ◽  
Jinfeng Wang ◽  
He Zhang ◽  
Jiao Li ◽  
Fuyong Wu
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Citric Acid ◽  
Bacterial Community ◽  
Root Exudates ◽  
Aromatic Hydrocarbons ◽  
Contaminated Soil ◽  
Corn Straw ◽  
Combined Application ◽  
Polycyclic Aromatic ◽  
Amended Soil

Abstract Root exudates can stimulate microbial degradation in rhizosphere, but it remains unclear whether the rhizodegradation of polycyclic aromatic hydrocarbons (PAHs) occurs in corn straw-amended soil. Hence, in the present study, either citric acid, a common low molecular weight organic acid in the root exudates, or corn straw was added into aged PAHs-contaminated soil to investigate their effectiveness in the biodegradation of PAHs. The present study showed that either corn straw (Y) or combined application of corn straw and citric acid (YN100) significantly (P < 0.05) enhanced the degradation of total PAHs in soil after 28 days incubation, which increased by 8.43% and 18.62% compared with control (CK), respectively. High-throughput sequencing suggested that both Y and YN100 treatments led to a shift in bacterial community in soil and increased the abundance of PAHs degraders. Interestingly, the copies of PAHs ring-hydroxylating-dioxygenase (PAH-RHD) Gram-negative bacteria (GN) genes under YN100 treatment was significantly (P < 0.05) higher than those under Y treatment in the soil. Network analysis showed that the potential hosts of PAH-RHDα genes were Lysobacter, Rhizobium, Bacillus, Devosia, Ohtaekwangia, Ramlibacter, Massilia, Steroidobacter, Phenylobacterium and Microvirga. Bacillus, Lysobacter, Rhizobium and Ohtaekwangia and all ten genera obviously increased under Y and YN100 treatments. These results indicate that combined application of corn straw and citric acid increased the PAH-degrading bacteria and PAH-RHDα genes, thus improving the biodegradability of PAHs in the soil. As these results verified, a combined corn straw-rhizosphere approach should be a feasible remediation strategy for PAHs-contaminated soil.

scholarly journals Remediation of Anthracene-Contaminated Soil with Sophorolipids-SDBS-Na2SiO3 and Treatment of Eluting Wastewater

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2188
Author(s):  
Wei Li ◽  
Xiaofeng Wang ◽  
Lixiang Shi ◽  
Xianyuan Du ◽  
Zhansheng Wang
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Organic Pollutants ◽  
Aromatic Hydrocarbons ◽  
Contaminated Soil ◽  
Ring Opening ◽  
Single Factor ◽  
Elution Time ◽  
Factor B ◽  
Ring Opening Reaction ◽  
Polycyclic Aromatic

The soil pollution of polycyclic aromatic hydrocarbons (PAHs) is serious in China, which not only affects the living and growing environment of plants and animals but also has a great impact on people’s health. The use of hydrophobic organic compounds to make use of surfactant ectopic elution processing is more convenient and cheaper as a repair scheme and can effectively wash out the polycyclic aromatic hydrocarbons in the soil. Therefore, we mixed sophorolipids:sodium dodecylbenzene sulfonate (SDBS):Na2SiO3 according to the mass ratio of 1:15:150. We explored the influencing factors of high and low concentrations of PAH-contaminated soil using a single factor test and four factors at a two-level factorial design. Then, the elution wastewater was treated by ultrasonic oxidation technology and the alkali-activated sodium persulfate technology. The results showed that: (1) In the single factor test, when the elution time is 8 h, the concentration of the compounded surfactant is 1200 mg/L, the particle size is 60 mesh, the concentration of NaCl is 100 mmol/L, and the concentration of KCl is 50 mmol/L, and the effect of the PAH-contaminated soil eluted by the composite surfactant is the best. Externally added NaCl and KCl salt ions have a more obvious promotion effect on the polycyclic aromatic hydrocarbon-contaminated soil; (2) in the interaction experiment, single factor B (elution time) and D (NaCl concentration) have a significant main effect. There is also a certain interaction between factor A (concentration agent concentration) and factor D, factor B, and factor C (KCl concentration); (3) the treatment of anthracene in the eluate by ultrasonic completely mineralizes the organic pollutants by the thermal and chemical effects produced by the ultrasonic cavitation phenomenon, so that the organic pollutants in the eluate are oxidized and degraded into simple environmentally friendly small molecular substances. When the optimal ultrasonic time is 60 min and the ratio of oxidant to activator is 1:2, the removal rate of contaminants in the eluent can reach 63.7%. At the same time, the turbidity of the eluent is significantly lower than that of the liquid after centrifugal separation, indicating that oxidants can not only remove the pollutants in elution water but also remove the residual soil particulate matter; and (4) by comparing the infrared spectrum of the eluted waste liquid before and after oxidation, it can be seen that during the oxidation process, the inner part of eluent waste liquid underwent a ring-opening reaction, and the ring-opening reaction also occurred in the part of the cyclic ester group of the surfactant, which changed from a ring to non-ring.

Microbial Properties and Degradation of Polycyclic Aromatic Hydrocarbons in the Contaminated Farmland Soil with Bioremediation

2014 ◽  
Vol 665 ◽  
pp. 534-537
Author(s):  
Hong Wang ◽  
Hai Bo Li ◽  
Xin Wang ◽  
Ji Fu Ma
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Contaminated Soil ◽  
Significant Positive Correlation ◽  
Removal Rate ◽  
Microbial Properties ◽  
Total Pahs ◽  
Farmland Soil ◽  
Polycyclic Aromatic ◽  
Microbial Agent

Degradation of polycyclic aromatic hydrocarbons (PAHs) and microbial quantity were investigated in aged PAHs-contaminated soil in a pot experiment with regrass and alfalfa. After 60 days germination the concentration of total PAHs in soil decreased by 37.57% and 38.41% with the treatment of ryegrass-microbe agent and alfalfa-microbe agent. The processes of ryegrass and alfalfa were 18.72% and 19.34%. The root system promoted the quantity of microbe and the microbial agent was benefit for the PAHs degrading microbe. And there was significant positive correlation between the number of PAHs degrading microorganisms and the removal rate of PAHs in the soil.

scholarly journals Stenotrophomonas sp. Pemsol isolated from crude oil contaminated soil in Mexico that can degrade polycyclic aromatic hydrocarbons and its whole genome sequence analyzed

2019 ◽  
Author(s):  
Temidayo O Elufisan ◽  
Isabel C Rodríguez-Luna ◽  
Omotayo O Oyedara ◽  
Alejandro Sánchez-Varela ◽  
Armando Hernandez Mendoza ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Crude Oil ◽  
Aromatic Hydrocarbons ◽  
Genome Analysis ◽  
Contaminated Soil ◽  
Antimicrobial Agents ◽  
Whole Genome ◽  
Chromatography Mass Spectrometry ◽  
Polycyclic Aromatic

Background: Stenotrophomonas are ubiquitous gram-negative bacteria which 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 antimicrobial agents because of their recalcitrant nature to many toxic compounds. Method. Stenotrophomonas sp. Pemsol was isolated from a crude oil contaminated soil. The capability of this isolate to tolerate and degrade polycyclic aromatic hydrocarbons (PAHs) (anthracene, anthraquinone, biphenyl, naphthalene, phenanthrene, phenanthridine and xylene) was evaluated on Bush Nell Hass medium containing PAHs as the unique 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). Results. Complete degradation of naphthalene at a concentration of 1 mg/mL was obtained and a newly formed catechol peak obtained from the UPLC-MS and GC-MS confirmed the degradation. The strain Pemsol lacked the ability to produce biosurfactant so that it cannot bio-emulsify PAHs. The whole genome analysis of Stenotrophomonas sp. Pemsol revealed a wealth of genes for hydrocarbon utilization and interaction with the environment and the presence of 147 genes associated with the degradation of PAHs, some of which are strain-specific on the genomic islands. Few genes are associated with bio-emulsification indicated that Pemsol without biosurfactant production has a genetic basis. This is the first report of the complete genome analysis sequence of a PAH-degrading Stenotrophomonas. Stenotrophomonas sp. Pemsol possesses features that makes it a good bacterium for genetic engineering and will therefore be a good tool for the remediation of crude oil or PAH-contaminated soil.

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