Negative Correlations Between Cultivable Pyrene-degrading Sphingomonas and Active Soil Pyrene Degraders Explain Bioaugmentation Postpone or Failure

Abstract Background: Bioaugmentation is an effective approach to remediate soils contaminated by polycyclic aromatic hydrocarbon (PAHs), but suffers from unsatisfactory performance in engineering practices. It is hypothetically explained by the complicated interactions between indigenous microbes and introduced degrading consortium. This study isolated a cultivable pyrene degrader (Sphingomonas sp. YT1005) and an active pyrene degrading consortium consisting of Gp16, Streptomyces, Pseudonocardia, Panacagrimonas, Methylotenera and Nitrospira by magnetic-nanoparticle mediated isolation (MMI) from soils.Results: Pyrene biodegradation was postponed in bioaugmentation with Sphingomonas sp. YT1005, explained by its negative correlations with the active pyrene degraders. In contrast, amendment with the active pyrene degrading consortium, pyrene degradation efficiency increased by 30.17%. In addition, pyrene degradation efficiency was positively correlated with the abundance of pyrene dioxygenase encoding genes (nidA, nidA3 and PAH-RHDα-GP), which significantly increased in MMI-isolated consortium. Pyrene degradation by Sphingomonas sp. YT1005 only followed the phthalate pathway, whereas the MMI-isolated pyrene degrading consortium exhibited both phthalate and salicylate pathways. The results indicated that Sphingomonas sp. YT1005 was not the actual pyrene degrader in soils, and MMI could successfully isolate the active pyrene degraders that were suitable for bioaugmentation.Conclusion: This work revealed the microbial intra-correlations during the bioaugmentation process, uncovered the underlying mechanisms of bioaugmentation postpone with cultivable degraders, and provided a deeper insight into the actual pyrene degraders and degradation pathways in PAHs contaminated soils. Our findings gave new explanations for bioaugmentation postpone or failure, and offered clues to enhance bioaugmentation performance by the active degraders using MMI.

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Removal of Bound PAH Residues in Contaminated Soils by Fenton Oxidation

Catalysts ◽

10.3390/catal9070619 ◽

2019 ◽

Vol 9 (7) ◽

pp. 619 ◽

Cited By ~ 4

Author(s):

Xuqiang Zhao ◽

Li Qin ◽

Michael Gatheru Waigi ◽

Pengfei Cheng ◽

Bing Yang ◽

...

Keyword(s):

Citric Acid ◽

Oxalic Acid ◽

Contaminated Soils ◽

Chelating Agent ◽

Fenton Oxidation ◽

Valuable Insight ◽

First Order Kinetics ◽

Bound Residues ◽

Polycyclic Aromatic ◽

Insight Into

The availability of bound residues of polycyclic aromatic hydrocarbons (PAHs), in reference to their parent compounds, can be enhanced by microbial activity and chemical reactions, which pose severe risks for the ecosystems encompassing contaminated soils. Considerable attention has been raised on how to remove these bound residues from PAH-contaminated soils. This paper provides a novel application of Fenton oxidation in the removal of bound residues of model PAHs, such as naphthalene (NAP), acenaphthene (ACP), fluorene (FLU) and anthracene (ANT), from naturally contaminated soils. The citric acid-enhanced Fenton treatment resulted in the degradation of bound PAH residues that followed pseudo-first-order kinetics, with rate constants within 4.22 × 10−2, 1.25 × 10−1 and 2.72 × 10−1 h−1 for NAP, FLU, and ANT, respectively. The reactivity of bound PAH residues showed a correlation with their ionization potential (IP) values. Moreover, the degradation rate of bound PAH residues was significantly correlated with H2O2-Fe2+ ratio (m/m) and H2O2 concentrations. The highest removal efficiencies of bound PAH residues was up to 89.5% with the treatment of chelating agent oxalic acid, which was demonstrated to be superior to other acids, such as citric acid and hydrochloric acid. This study provides valuable insight into the feasibility of citric acid-Fenton and oxalic acid-Fenton treatments in rehabilitating bound PAH residues in contaminated soils.

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Comparison of oxidoreductive enzyme activities in three coal tar creosote-contaminated soils

Soil Research ◽

10.1071/sr19040 ◽

2019 ◽

Vol 57 (8) ◽

pp. 814 ◽

Cited By ~ 2

Author(s):

Arkadiusz Telesiński ◽

Teresa Krzyśko-Łupicka ◽

Krystyna Cybulska ◽

Barbara Pawłowska ◽

Robert Biczak ◽

...

Keyword(s):

Contaminated Soils ◽

Sandy Loam ◽

Coal Tar ◽

Loamy Sand ◽

Clay Loam ◽

Oxidoreductase Activity ◽

Sandy Clay Loam ◽

Sandy Clay ◽

Polycyclic Aromatic ◽

Negative Effect

This study used laboratory experiments to compare the effects of coal tar creosote on the activity of oxidoreductive enzymes in sandy loam, loamy sand and sandy clay loam soils. Different amounts of coal tar creosote were added to soil samples as follows: 0 (control), 2, 10 or 50 g kg–1 dry matter. The activity of soil dehydrogenases (DHAs), o-diphenol oxidase (o-DPO), catalase (CAT), nitrate reductase (NR) and peroxidases (POX) was determined. Contamination of soil with coal tar creosote affected oxidoreductase activity. Oxidoreductive enzyme activity following soil contamination with coal tar creosote was in the following order: DHAs > CAT > NR > POX > o-DPO in loamy sand and in sandy loam; and DHAs > POX > CAT > NR > o-DPO in sandy clay loam. The index of soil oxidoreductive activity (IOx) introduced in this study confirms the negative effect of coal tar creosote on oxidoreductase activity in soil. DHAs were the most sensitive to the contamination of soil with coal tar creosote. Moreover, the greatest changes in oxidoreductase activities were observed in loamy sand. Knowledge of the mechanism underlying the effects of coal tar creosote on oxidoreductive processes may enable development of a method for the bioremediation of polycyclic aromatic hydrocarbon-contaminated soils.

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Remediation of mercury-contaminated soils and sediments using biochar: a critical review

Biochar ◽

10.1007/s42773-021-00087-1 ◽

2021 ◽

Author(s):

Qian Yang ◽

Yongjie Wang ◽

Huan Zhong

Keyword(s):

Health Risks ◽

Contaminated Soils ◽

Functional Materials ◽

Redox Conditions ◽

Existing Problems ◽

Soils And Sediments ◽

Underlying Mechanisms ◽

Biochar Amendment

AbstractThe transformation of mercury (Hg) into the more toxic and bioaccumulative form methylmercury (MeHg) in soils and sediments can lead to the biomagnification of MeHg through the food chain, which poses ecological and health risks. In the last decade, biochar application, an in situ remediation technique, has been shown to be effective in mitigating the risks from Hg in soils and sediments. However, uncertainties associated with biochar use and its underlying mechanisms remain. Here, we summarize recent studies on the effects and advantages of biochar amendment related to Hg biogeochemistry and its bioavailability in soils and sediments and systematically analyze the progress made in understanding the underlying mechanisms responsible for reductions in Hg bioaccumulation. The existing literature indicates (1) that biochar application decreases the mobility of inorganic Hg in soils and sediments and (2) that biochar can reduce the bioavailability of MeHg and its accumulation in crops but has a complex effect on net MeHg production. In this review, two main mechanisms, a direct mechanism (e.g., Hg-biochar binding) and an indirect mechanism (e.g., biochar-impacted sulfur cycling and thus Hg-soil binding), that explain the reduction in Hg bioavailability by biochar amendment based on the interactions among biochar, soil and Hg under redox conditions are highlighted. Furthermore, the existing problems with the use of biochar to treat Hg-contaminated soils and sediments, such as the appropriate dose and the long-term effectiveness of biochar, are discussed. Further research involving laboratory tests and field applications is necessary to obtain a mechanistic understanding of the role of biochar in reducing Hg bioavailability in diverse soil types under varying redox conditions and to develop completely green and sustainable biochar-based functional materials for mitigating Hg-related health risks.

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Mechanistic Insight into the Degradation Pathways of P-cresol in Ozonation, Peroxone, and Ozone-persulfate Process

Ozone Science and Engineering ◽

10.1080/01919512.2020.1846495 ◽

2020 ◽

pp. 1-13

Author(s):

Su-Huan Kow ◽

Muhammad Ridwan Fahmi ◽

Che Zulzikrami Azner Abidin ◽

Soon-an Ong

Keyword(s):

Degradation Pathways ◽

Mechanistic Insight ◽

Insight Into

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Gut Microbiome and Metabolome Profiles Associated with High-Fat Diet in Mice

Metabolites ◽

10.3390/metabo11080482 ◽

2021 ◽

Vol 11 (8) ◽

pp. 482

Author(s):

Jae-Kwon Jo ◽

Seung-Ho Seo ◽

Seong-Eun Park ◽

Hyun-Woo Kim ◽

Eun-Ju Kim ◽

...

Keyword(s):

Gut Microbiota ◽

Relative Abundance ◽

High Fat Diet ◽

Amplicon Sequencing ◽

Gas Chromatography Mass Spectrometry ◽

Control Group ◽

Rrna Gene ◽

High Fat ◽

Underlying Mechanisms ◽

Insight Into

Obesity can be caused by microbes producing metabolites; it is thus important to determine the correlation between gut microbes and metabolites. This study aimed to identify gut microbiota-metabolomic signatures that change with a high-fat diet and understand the underlying mechanisms. To investigate the profiles of the gut microbiota and metabolites that changed after a 60% fat diet for 8 weeks, 16S rRNA gene amplicon sequencing and gas chromatography-mass spectrometry (GC-MS)-based metabolomic analyses were performed. Mice belonging to the HFD group showed a significant decrease in the relative abundance of Bacteroidetes but an increase in the relative abundance of Firmicutes compared to the control group. The relative abundance of Firmicutes, such as Lactococcus, Blautia, Lachnoclostridium, Oscillibacter, Ruminiclostridium, Harryflintia, Lactobacillus, Oscillospira, and Erysipelatoclostridium, was significantly higher in the HFD group than in the control group. The increased relative abundance of Firmicutes in the HFD group was positively correlated with fecal ribose, hypoxanthine, fructose, glycolic acid, ornithine, serum inositol, tyrosine, and glycine. Metabolic pathways affected by a high fat diet on serum were involved in aminoacyl-tRNA biosynthesis, glycine, serine and threonine metabolism, cysteine and methionine metabolism, glyoxylate and dicarboxylate metabolism, and phenylalanine, tyrosine, and trypto-phan biosynthesis. This study provides insight into the dysbiosis of gut microbiota and metabolites altered by HFD and may help to understand the mechanisms underlying obesity mediated by gut microbiota.

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Advancing prediction of polycyclic aromatic hydrocarbon bioaccumulation in plants for historically contaminated soils using Lolium multiflorum and simple chemical in-vitro methodologies

The Science of The Total Environment ◽

10.1016/j.scitotenv.2020.144783 ◽

2021 ◽

Vol 772 ◽

pp. 144783

Author(s):

Atefeh Esmaeili ◽

Oliver Knox ◽

Albert Juhasz ◽

Susan C. Wilson

Keyword(s):

Polycyclic Aromatic Hydrocarbon ◽

Aromatic Hydrocarbon ◽

Contaminated Soils ◽

Lolium Multiflorum ◽

Simple Chemical ◽

Polycyclic Aromatic

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Specificities and Synergistic Actions of Novel PL8 and PL7 Alginate Lyases from the Marine Fungus Paradendryphiella salina

Journal of Fungi ◽

10.3390/jof7020080 ◽

2021 ◽

Vol 7 (2) ◽

pp. 80

Author(s):

Bo Pilgaard ◽

Marlene Vuillemin ◽

Jesper Holck ◽

Casper Wilkens ◽

Anne S. Meyer

Keyword(s):

Alginate Lyase ◽

Marine Fungus ◽

Brown Macroalgae ◽

Polysaccharide Lyases ◽

Alginate Lyases ◽

Encoding Genes ◽

Substrate Affinities ◽

Alginate Degradation ◽

Insight Into

Alginate is an anionic polysaccharide abundantly present in the cell walls of brown macroalgae. The enzymatic depolymerization is performed solely by alginate lyases (EC 4.2.2.x), categorized as polysaccharide lyases (PLs) belonging to 12 different PL families. Until now, the vast majority of the alginate lyases have been found in bacteria. We report here the first extensive characterization of four alginate lyases from a marine fungus, the ascomycete Paradendryphiella salina, a known saprophyte of seaweeds. We have identified four polysaccharide lyase encoding genes bioinformatically in P. salina, one PL8 (PsMan8A), and three PL7 alginate lyases (PsAlg7A, -B, and -C). PsMan8A was demonstrated to exert exo-action on polymannuronic acid, and no action on alginate, indicating that this enzyme is most likely an exo-acting polymannuronic acid specific lyase. This enzyme is the first alginate lyase assigned to PL8 and polymannuronic acid thus represents a new substrate specificity in this family. The PL7 lyases (PsAlg7A, -B, and -C) were found to be endo-acting alginate lyases with different activity optima, substrate affinities, and product profiles. PsAlg7A and PsMan8A showed a clear synergistic action for the complete depolymerization of polyM at pH 5. PsAlg7A depolymerized polyM to mainly DP5 and DP3 oligomers and PsMan8A to dimers and monosaccharides. PsAlg7B and PsAlg7C showed substrate affinities towards both polyM and polyG at pH 8, depolymerizing both substrates to DP9-DP2 oligomers. The findings elucidate how P. salina accomplishes alginate depolymerization and provide insight into an efficient synergistic cooperation that may provide a new foundation for enzyme selection for alginate degradation in seaweed bioprocessing.

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