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1.
Braz. j. biol ; 83: e242536, 2023. tab, graf
Article in English | MEDLINE, LILACS, VETINDEX | ID: biblio-1339356

ABSTRACT

Abstract Chromium (VI) a highly toxic metal, a major constituent of industrial waste. It is continuously release in soil and water, causes environmental and health related issues, which is increasing public concern in developing countries like Pakistan. The basic aim of this study was isolation and screening of chromium resistant bacteria from industrial waste collected from Korangi and Lyari, Karachi (24˚52ʹ46.0ʺN 66˚59ʹ25.7ʺE and 24˚48ʹ37.5ʺN 67˚06ʹ52.6ʺE). Among total of 53 isolated strains, seven bacterial strains were selected through selective enrichment and identified on the basis of morphological and biochemical characteristics. These strains were designated as S11, S13, S17, S18, S30, S35 and S48, resistance was determined against varying concentrations of chromium (100-1500 mg/l). Two bacterial strains S35 and S48 showed maximum resistance to chromium (1600 mg/l). Bacterial strains S35 and S48 were identified through 16S rRNA sequence and showed 99% similarity to Bacillus paranthracis and Bacillus paramycoides. Furthermore, growth condition including temperature and pH were optimized for both bacterial strains, showed maximum growth at temperature 30ºC and at optimum pH 7.5 and 6.5 respectively. It is concluded that indigenous bacterial strains isolated from metal contaminated industrial effluent use their innate ability to transform toxic heavy metals to less or nontoxic form and can offer an effective tool for monitoring heavy metal contamination in the environment.


Resumo O cromo (VI), metal altamente tóxico, é um dos principais constituintes dos resíduos industriais. É liberado no solo e na água, causa problemas ambientais e de saúde de crescente preocupação pública em países em desenvolvimento como o Paquistão. O objetivo básico deste estudo foi o isolamento e a triagem de bactérias resistentes ao cromo de resíduos industriais coletados em Korangi e Lyari, Karachi (24˚52'46,0"N 66˚59'25,7"E e 24˚48'37,5"N 67˚06'52,6"E). Do total de 53 cepas isoladas, sete cepas bacterianas foram selecionadas por enriquecimento seletivo e identificadas com base em características morfológicas e bioquímicas. Essas cepas foram designadas como S11, S13, S17, S18, S30, S35 e S48, apresentaram alta resistência aos metais contra concentrações variáveis (100-1500 mg / l) de cromo. Já as cepas S35 e S48 foram identificadas por meio da sequência 16S rRNA e apresentaram 99% de similaridade com Bacillus paranthracis e Bacillus paramycoides. Além disso, as condições de crescimento incluindo temperatura e pH foram otimizadas e ambas as cepas bacterianas apresentaram crescimento máximo na temperatura de 30 ºC, enquanto seu pH ótimo foi observado em 7,5 e 6,5, respectivamente. Conclui-se que o potencial de resistência dessas bactérias resistentes ao cromo pode ser efetivamente utilizado na remoção de cromo de efluentes industriais contaminados. Técnicas de base biológica usando bactérias ajudarão a fornecer métodos mais baratos e ecológicos de remoção, recuperação e desintoxicação de cromo.


Subject(s)
Chromium , Metals, Heavy , Bacillus , Bacteria/genetics , Biodegradation, Environmental , RNA, Ribosomal, 16S/genetics , Industrial Waste/analysis
2.
Braz. j. biol ; 83: e242830, 2023. tab, graf
Article in English | MEDLINE, LILACS, VETINDEX | ID: biblio-1278540

ABSTRACT

Abstract Pesticide residues that contaminate the environment circulate within the hydrological cycle can accumulate within the food chain and cause problems to both environmental and human health. Microbes, however, are well known for their metabolic versatility and the ability to degrade chemically stable substances, including recalcitrant xenobiotics. The current study focused on bio-prospecting within Amazonian rainforest soils to find novel strains fungi capable of efficiently degrading the agriculturally and environmentally ubiquitous herbicide, glyphosate. Of 50 fungal strains isolated (using culture media supplemented with glyphosate as the sole carbon-substrate), the majority were Penicillium strains (60%) and the others were Aspergillus and Trichoderma strains (26 and 8%, respectively). All 50 fungal isolates could use glyphosate as a phosphorous source. Eight of these isolates grew better on glyphosate-supplemented media than on regular Czapek Dox medium. LC-MS revealed that glyphosate degradation by Penicillium 4A21 resulted in sarcosine and aminomethylphosphonic acid.


Resumo Resíduos de agrotóxicos que contaminam o meio ambiente circulam no ciclo hidrológico, podendo se acumular na cadeia alimentar e causar problemas tanto à saúde ambiental quanto humana. Por sua vez, microrganismos são bem conhecidos por sua versatilidade metabólica e capacidade de degradar substâncias quimicamente estáveis, incluindo xenobióticos recalcitrantes. O estudo atual se concentrou na bioprospecção nos solos da floresta amazônica para encontrar novas linhagens de fungos capazes de degradar com eficiência o herbicida onipresente na agricultura e no meio ambiente, o glifosato. Entre os 50 fungos isolados (usando meio de cultura suplementado com glifosato como única fonte de carbono), a maioria eram isolados do gênero Penicillium (60%) e os outros eram isolados de Aspergillus e Trichoderma (26 e 8%, respectivamente). Todos os 50 isolados de fungos foram capazes de usar glifosato como fonte de fósforo. Oito desses isolados cresceram melhor em meio suplementado com glifosato do que em meio Czapek Dox regular. LC-MS revelou que a degradação do glifosato por Penicillium 4A21 resultou nos metabólitos sarcosina e ácido aminometilfosfônico.


Subject(s)
Humans , Penicillium , Trichoderma , Herbicides/toxicity , Aspergillus , Soil , Soil Microbiology , Biodegradation, Environmental , Organophosphonates , Fungi , Glycine/analogs & derivatives
3.
Braz. j. biol ; 82: e244703, 2022. tab, graf
Article in English | MEDLINE, LILACS, VETINDEX | ID: biblio-1278506

ABSTRACT

Abstract In this study, oil degrading bacteria discovered from fish living near the oil ports at Karachi in Pakistan were characterized. The bacteria isolated from skin, gills, and gut in fish could consume crude oil as a source of carbon and energy. Total 36 isolates were tested using Nutrient Agar (NA) and MSA media with different crude oil concentrations (0.2%, 0.5%, 0.7%, 1%, 2%, and 5%) and 4 out of 36 isolates (two Gram positive and two Gram negative bacteria) were selected for further identification. 16S rRNA gene sequencing revealed that the isolates are related to Bacillus velezensis, Bacillus flexus, Pseudomonas brenneri and Pseudomonas azotoforman. Oil degrading potential of these bacteria was characterized by GC-MS analysis of degradation of oil components in crude oil as well as engine oil. We found that one (2, 6, 10, 14-Tetramethylpentadecane) out of 42 components in the crude oil was fully eliminated and the other oil components were reduced. In addition, 26 out of 42 oil components in the engine oil, were fully eliminated and the rest were amended. Taken together, these studies identify that B. velezensis, B. flexus, P. brenneri and P. azotoforman have high oil degrading potential, which may be useful for degradation of oil pollutants and other commercial applications.


Resumo Neste estudo, bactérias degradadoras de óleo descobertas em peixes que vivem perto dos portos de petróleo em Karachi, no Paquistão, foram caracterizadas. As bactérias isoladas da pele, guelras e intestinos dos peixes podem consumir petróleo bruto como fonte de carbono e energia. No total, 36 isolados foram testados usando Agar Nutriente (NA) e meio MSA com diferentes concentrações de óleo bruto (0,2%, 0,5%, 0,7%, 1%, 2% e 5%) e 4 de 36 isolados (dois Gram positivos e duas bactérias Gram negativas) foram selecionadas para posterior identificação. O sequenciamento do gene 16S rRNA revelou que os isolados estão relacionados a Bacillus velezensis, Bacillus flexus, Pseudomonas brenneri e Pseudomonas azotoforman. O potencial de degradação do óleo dessas bactérias foi caracterizado pela análise de GC-MS da degradação dos componentes do óleo no óleo cru, bem como no óleo do motor. Descobrimos que um (2, 6, 10, 14-tetrametilpentadecano) de 42 componentes do óleo cru foi totalmente eliminado e os outros componentes do óleo foram reduzidos. Além disso, 26 dos 42 componentes do óleo do motor foram totalmente eliminados e o restante corrigido. Juntos, esses estudos identificam que B. velezensis, B. flexus, P. brenneri e P. azotoforman têm alto potencial de degradação de óleo, o que pode ser útil para a degradação de poluentes de óleo e outras aplicações comerciais.


Subject(s)
Animals , Petroleum , Pakistan , Pseudomonas , Bacillus , Bacteria/genetics , Biodegradation, Environmental , RNA, Ribosomal, 16S/genetics , Indian Ocean , Fishes
4.
Braz. j. biol ; 82: e237386, 2022. graf
Article in English | LILACS | ID: biblio-1249227

ABSTRACT

Abstract Shewanella xiamenensis G5-03 was observed to decolorize the azo dye Congo red in synthetic wastewater. The influence of some factors on the dye decolorization efficiency was evaluated. The optimal decolorization conditions were temperature 30-35 °C, pH 10.0, incubation time 10 h, and static condition. The kinetic of Congo red decolorization fitted to the Michaelis-Menten model (Vmax = 111.11 mg L-1 h-1 and Km = 448.3 mg L-1). The bacterium was also able to degrade benzidine, a product of azo bond breakage of the Congo red, which contributed to reduce the phytotoxicity. The ability of S. xiamenensis G5-03 for simultaneous decolorization and degradation of Congo red shows its potential application for the biological treatment of wastewaters containing azo dyes.


Resumo Shewanella xiamenensis G5-03 foi capaz de descolorir o corante azo vermelho Congo em água residuária sintética. A influência de alguns fatores na eficiência da descoloração do corante foi avaliada. As condições ótimas de descoloração foram temperatura de 30-35 °C, pH 10,0 e condições estáticas. A cinética de descoloração do vermelho Congo se ajustou ao modelo de Michaelis-Menten (Vmax = 111,11 mg L-1 h-1 and Km = 448,3 mg L-1). A bactéria também foi capaz de degradar a benzidina, um produto da quebra da ligação azo do vermelho Congo, o que contribuiu para a redução da fitotoxicidade. A habilidade da S. xiamenensis G5-03 em simultaneamente descolorir e degradar o vermelho Congo demostra seu potencial de aplicação no tratamento de águas residuárias contendo corantes azo.


Subject(s)
Azo Compounds , Congo Red , Benzidines , Biodegradation, Environmental , Shewanella , Coloring Agents
5.
Arq. Inst. Biol ; 88: e00622019, 2021. graf
Article in English | LILACS, VETINDEX | ID: biblio-1146670

ABSTRACT

Aristolochia plants are notable from an ethnopharmacological viewpoint, but the relevance of these species for medicinal purposes has been debated because of their inherent toxicity. The convergence of these contrasting realities can be readily achieved using bioconversion methods, which have been shown to be useful tools for numerous applications, including the detoxification of biomass. In this context, methanolic extracts of leaves from Aristolochia triangularis and Aristolochia gibertii, as well as the feces of Battus polydamas larvae fed with leaves from these plants, were prepared, and their cytotoxic activities were evaluated on a human fibroblast cell line (GM07492). The leaf extracts were found to be cytotoxic, leading to reductions of 42.1 and 33.8% on cell viability, respectively, while the fecal extracts were considered inactive. In addition to evidencing the cytotoxicity of A. triangularis and A. gibertii, these findings demonstrated a potential bioconversion strategy for obtaining aristolochiaceous extracts with reduced toxicity using the larvae of a specialist phytophagous insect, thus renewing expectations in relation to the pharmacological importance of Aristolochia spp. The results were also ecologically relevant, as B. polydamas larvae were found to be able to detoxify compounds from host plants.(AU)


Subject(s)
Biodegradation, Environmental , Aristolochiaceae , Toxicity , Cell Line , Fibroblasts , Insecta , Larva
6.
Braz. j. biol ; 81(2): 398-405, 2021. tab, graf, ilus
Article in English | MEDLINE, LILACS, VETINDEX | ID: biblio-1153348

ABSTRACT

Continuous occurrence of heavy metals is a major cause of environmental pollution due to its toxic effects. At minimum concentrations, these metals are highly reactive and can gather in the food chains and food web, causing major dangers to public health concerns. Soil samples were collected from Paharang drain, Faisalabad. Cadmium tolerant bacteria were isolated and evaluated for their MIC against Cd. The isolated bacterial strain GCFSD01 showed MIC value upto 30 mM/L. The bacterial strain with the highest resistance against Cd was selected for further study. Molecular characterization of bacterial isolate GCFSD01 was performed by 16S rRNA which confirmed it as Bacillus cereus. Optimum growth conditions of bacterial strain were also evaluated. Strain GCFSD01 showed optimum growth at pH 7 and 37 °C temperature. Our result revealed that B. cereus strain GCFSD01 reduced 61.3% Cd after 48 hrs. Multiple metal tolerance and Cd reduction by B. cereus indicate its potential for further use for decontamination of polluted soil.


A ocorrência contínua de metais pesados é uma das principais causas de poluição ambiental devido aos seus efeitos tóxicos. A contaminação por metais pesados representa um grande risco para todas as formas de vida encontradas no meio ambiente. Em concentrações mínimas, esses metais são altamente reativos e podem se acumular nas cadeias alimentares e na cadeia alimentar, causando grandes perigos às preocupações com a saúde pública. Amostras de solo foram coletadas no esgoto de Paharang, Faisalabad. Bactérias tolerantes ao cádmio foram isoladas da amostra coletada pelo método da placa de ágar. As colônias separadas individuais selecionadas foram avaliadas quanto às suas concentrações inibitórias mínimas contra Cd. A cepa bacteriana isolada GCFSD01 apresentou valores de CIM de 30 mM/L. A colônia bacteriana que apresentou maior resistência contra o Cd foi selecionada para identificação. Após seleção da maior colônia bacteriana resistente ao Cd, coloração de Gram e diferentes testes bioquímicos foram realizados para a caracterização da bactéria isolada. A caracterização molecular do isolado bacteriano GCFSD01 foi realizada por PCR 16S rRNA confirmando a presença de Bacillus cereus. Após a identificação molecular, as condições ótimas de crescimento da cepa bacteriana também foram verificadas. A cepa GCFSD01 apresentou crescimento ótimo em pH 7 e temperatura de 37 °C. Nosso resultado revelou que a cepa de B. cereus GCFSD01 reduziu 61,3% de Cd após 48 horas. A tolerância a múltiplos metais e a redução de Cd por B. cereus indicam seu potencial para uso posterior na descontaminação do solo poluído.


Subject(s)
Soil Pollutants/toxicity , Bacillus cereus/genetics , Cadmium/toxicity , Industrial Effluents/adverse effects , Metals, Heavy/analysis , Soil , Soil Microbiology , Biodegradation, Environmental , RNA, Ribosomal, 16S/genetics
7.
Chinese Journal of Biotechnology ; (12): 2765-2778, 2021.
Article in Chinese | WPRIM | ID: wpr-887839

ABSTRACT

Petroleum hydrocarbon pollutants are difficult to be degraded, and bioremediation has received increasing attention for remediating the hydrocarbon polluted area. This review started by introducing the interphase adaptation and transport process of hydrocarbon by microbes. Subsequently, the advances made in the identification of hydrocarbon-degrading strains and genes as well as elucidation of metabolic pathways and underpinning mechanisms in the biodegradation of typical petroleum hydrocarbon pollutants were summarized. The capability of wild-type hydrocarbon degrading bacteria can be enhanced through genetic engineering and metabolic engineering. With the rapid development of synthetic biology, the bioremediation of hydrocarbon polluted area can be further improved by engineering the metabolic pathways of hydrocarbon-degrading microbes, or through design and construction of synthetic microbial consortia.


Subject(s)
Bacteria/genetics , Biodegradation, Environmental , Hydrocarbons , Petroleum , Petroleum Pollution/analysis , Soil Microbiology , Soil Pollutants
8.
Chinese Journal of Biotechnology ; (12): 2688-2702, 2021.
Article in Chinese | WPRIM | ID: wpr-887834

ABSTRACT

Plastics are widely used in daily life. Due to poor management and disposal, about 80% of plastic wastes were buried in landfills and eventually became land and ocean waste, causing serious environmental pollution. Recycling plastics is a desirable approach, but not applicable for most of the plastic waste. Microbial degradation offers an environmentally friendly way to degrade the plastic wastes, and this review summarizes the potential microbes, enzymes, and the underpinning mechanisms for degrading six most commonly used plastics including polyethylene terephthalate, polyethylene, polyvinyl chloride, polypropylene, polystyrene and polyurethane. The challenges and future perspectives on microbial degradation of plastics were proposed.


Subject(s)
Biodegradation, Environmental , Plastics , Polyurethanes , Recycling
9.
Chinese Journal of Biotechnology ; (12): 2474-2482, 2021.
Article in Chinese | WPRIM | ID: wpr-887813

ABSTRACT

Spirodela polyrrhiza is a floating plant widely used in biomass utilization and eutrophication phytoremediation. It becomes a common aquatic plant everywhere with the increasingly serious eutrophication. It has been reported that S. polyrrhiza has a good effect on the remediation of eutrophication water. In order to study the absorption and transportation of phosphorus in S. polyrrhiza, we extracted RNA from S. polyrrhiza and then reverse transcribed it into cDNA, which was used as a template to amplify a specific fragment. The full-length sequence of the open reading frame (ORF) was 1 620 bp, encoding 539 amino acids, named SpPHT1;1, and the accession number in GenBank was MN720003. Bioinformatical analysis showed that SpPHT1;1 had no intron. The protein it encoded was a stable, hydrophobic protein with 11 transmembrane domains. SpPHT1;1 structure was similar to that of major facilitator superfamily (MFS) superfamily members. The cluster analysis showed that SpPHT1;1 was closely related to ZMPHT2 in maize and SBPHT1-8 in sorghum. So, it might belong to plant PHT1 family. The expression of SpPHT1;1 in leaf was significantly more than that of root under normal phosphorus condition. Low phosphorus condition could promote gene expression, and the relative expression level of SpPHT1;1 arrived at the peak at 48 h both in root and leaf. High phosphorus condition could inhibit gene expression. These results indicated that SpPHT1;1 expression would be affected by external phosphorus concentration. The results of this study are helpful for further research on the function of phosphate transporter. It also can provide theoretical basis for further development and utilization of S. polyrrhiza.


Subject(s)
Araceae/genetics , Biodegradation, Environmental , Cloning, Molecular , DNA, Complementary , Phosphate Transport Proteins/genetics
10.
Chinese Journal of Biotechnology ; (12): 3696-3707, 2021.
Article in Chinese | WPRIM | ID: wpr-921458

ABSTRACT

Polycyclic aromatic hydrocarbons (PAHs) are a class of common environmental pollutants that pose threats to human health. In this study, a mesophilic bacterial strain CFP312 (grown at 15-37 °C, optimal at 30 °C) was isolated from PAHs-contaminated soil samples. It was identified as Moraxella sp. by morphological observation, physiological and biochemical test, and 16S rRNA gene phylogeny analysis. This is the first reported PAHs degrading strains in Moraxella. Degradation analysis showed that 84% and 90% of the loaded phenanthrene (400 mg/L) were degraded within 48 h and 60 h, and the degradation rates reached 1.21 and 1.29 mg/(L·h), respectively. During the degradation of phenanthrene, phenanthrene-3,4-dihydrodiol was detected as an intermediate. Based on this, it was proposed that double oxygenation at the positions 3 and 4 of phenanthrene was the first step of biodegradation. Adaptability of strain CFP312 to different enhanced phenanthrene-degradation systems was tested in aqueous-organic system, micellar aqueous system, and cloud point system. Strain CFP312 showed good adaptability to different systems. In addition, the bacterium can rapidly degrade the phenanthrene in contaminated soil in slurry-aqueous system, indicating great potential in environmental remediation.


Subject(s)
Biodegradation, Environmental , Humans , Phenanthrenes , Polycyclic Aromatic Hydrocarbons , RNA, Ribosomal, 16S/genetics , Soil Microbiology , Soil Pollutants
11.
Chinese Journal of Biotechnology ; (12): 3675-3684, 2021.
Article in Chinese | WPRIM | ID: wpr-921456

ABSTRACT

Biodegradation of polyurethane (PUR) pollutants by microorganisms has received widespread attention currently. Identification of microorganisms capable of efficiently degrading PUR plastics is a key point. In this study, a strain P10 capable of degrading PUR was isolated from the plastic wastes, and identified as a bacterium belonging to the genus of Brevibacillus based on colony morphology and 16S rDNA phylogenetic analysis. Brevibacillus sp. P10 was capable of degrading 71.4% of waterborne polyurethane (Impranil DLN) after 6 days growth in MSM medium with DLN as a sole carbon source. In addition, strain P10 can use commercial PUR foam as the sole carbon source for growth. Brevibacillus sp. P10 can degrade 50 mg PUR foam after 6 days growth in MSM medium supplemented with 5% (V/V) LB after optimization of degradation conditions. This indicates that Brevibacillus sp. P10 has potential to be used in biodegradation of PUR waste.


Subject(s)
Bacteria , Biodegradation, Environmental , Phylogeny , Polyurethanes
12.
Chinese Journal of Biotechnology ; (12): 3653-3662, 2021.
Article in Chinese | WPRIM | ID: wpr-921454

ABSTRACT

Microorganisms are the dominant players driving the degradation and transformation of chloramphenicol (CAP) in the environment. However, little bacterial strains are able to efficiently degrade and mineralize CAP, and the CAP degrading pathways mediated by oxidative reactions remain unclear. In this study, a highly efficient CAP-degrading microbial consortium, which mainly consists of Rhodococcus (relative abundance >70%), was obtained through an enrichment process using CAP-contaminated activated sludge as the inoculum. A bacterial strain CAP-2 capable of efficiently degrading CAP was isolated from the consortium and identified as Rhodococcus sp. by 16S rRNA gene analysis. Strain CAP-2 can efficiently degrade CAP under different nutrient conditions. Based on the biotransformation characteristics of the detected metabolite p-nitrobenzoic acid and the reported metabolites p-nitrobenzaldehyde and protocatechuate by strain CAP-2, a new oxidative pathway for the degradation of CAP was proposed. The side chain of CAP was oxidized and broken to generate p-nitrobenzaldehyde, which was further oxidized to p-nitrobenzoic acid. Strain CAP-2 can be used to further study the molecular mechanism of CAP catabolism, and has the potential to be used in in situ bioremediation of CAP-contaminated environment.


Subject(s)
Biodegradation, Environmental , Chloramphenicol , RNA, Ribosomal, 16S/genetics , Rhodococcus/genetics , Sewage
13.
Chinese Journal of Biotechnology ; (12): 3636-3652, 2021.
Article in Chinese | WPRIM | ID: wpr-921453

ABSTRACT

With continuous improvement of people's living standards, great efforts have been paid to environmental protection. Among those environmental issues, soil contamination by petroleum hydrocarbons has received widespread concerns due to the persistence and the degradation difficulty of the pollutants. Among the various remediation technologies, in-situ microbial remediation enhancement technologies have become the current hotspot because of its low cost, environmental friendliness, and in-situ availability. This review summarizes several in-situ microbial remediation technologies such as bioaugmentation, biostimulation, and integrated remediation, as well as their engineering applications, providing references for the selection of in-situ bioremediation technologies in engineering applications. Moreover, this review discusses future research directions in this area.


Subject(s)
Biodegradation, Environmental , Humans , Hydrocarbons , Petroleum , Soil , Soil Microbiology , Soil Pollutants
14.
Chinese Journal of Biotechnology ; (12): 3622-3635, 2021.
Article in Chinese | WPRIM | ID: wpr-921452

ABSTRACT

Bioremediation is considered as a cost-effective, efficient and free-of-secondary-pollution technology for petroleum pollution remediation. Due to the limitation of soil environmental conditions and the nature of petroleum pollutants, the insufficient number and the low growth rate of indigenous petroleum-degrading microorganisms in soil lead to long remediation cycle and poor remediation efficiency. Bioaugmentation can effectively improve the biodegradation efficiency. By supplying functional microbes or microbial consortia, immobilized microbes, surfactants and growth substrates, the remediation effect of indigenous microorganisms on petroleum pollutants in soil can be boosted. This article summarizes the reported petroleum-degrading microbes and the main factors influencing microbial remediation of petroleum contaminated soil. Moreover, this article discusses a variety of effective strategies to enhance the bioremediation efficiency, as well as future directions of bioaugmentation strategies.


Subject(s)
Biodegradation, Environmental , Petroleum , Soil , Soil Microbiology , Soil Pollutants
15.
Chinese Journal of Biotechnology ; (12): 3604-3621, 2021.
Article in Chinese | WPRIM | ID: wpr-921451

ABSTRACT

The remediation of heavy-metal (HM) contaminated soil using hyperaccumulators is one of the important solutions to address the inorganic contamination widely occurred worldwide. Hyperaccumulators are able to hyperaccumulate HMs, but their planting, growth, and extraction capacities are greatly affected by HM stress. The application of arbuscular mycorrhizal fungi (AMF) enhances the function of hyperaccumulators by combining the functional advantages of both, improving the efficiency of remediation, shortening the remediation cycle, and maintaining the stability and persistence of the remediation. Thus, the combined use of AMF with hyperaccumulators has broad prospects for application in the management of increasingly complex and severe HM pollution. This review starts by defining the concept of hyperaccumulators, followed by describing the typical hyperaccumulators that were firstly reported in China as well as those known to form symbioses with AMF. This review provides a systematic and in-depth discussion of the effects of AMF on the growth of hyperaccumulators, as well as the absorption and accumulation of HMs, the effects and mechanism on the hyperaccumulator plus AMF symbiosis to absorb and accumulate HMs. AMF enhances the function of hyperaccumulators on the absorption and accumulation of HMs by regulating the physicochemical and biological conditions in the plant rhizosphere, the situation of elements homeostasis, the physiological metabolism and gene expression. Moreover, the symbiotic systems established by hyperaccumulators plus AMF have the potential to combine their abilities to remediate HMs-contaminated habitat. Finally, challenges for the combined use of remediation technologies for hyperaccumulator plus AMF symbiosis and future directions were prospected.


Subject(s)
Biodegradation, Environmental , Metals, Heavy , Mycorrhizae/chemistry , Plant Roots/chemistry , Soil Pollutants , Symbiosis
16.
Chinese Journal of Biotechnology ; (12): 3591-3603, 2021.
Article in Chinese | WPRIM | ID: wpr-921450

ABSTRACT

Wet detoxification has traditionally been seen as the most promising technology for treating chromium-contaminated sites. However, the addition of chemicals in the wet detoxification process not only increases the cost but also introduces extra pollutants. Moreover, the chromium-containing slag may be re-dissolved in the form of Cr(VI), and the increased concentration of Cr(VI) results in a serious "returning to yellow" phenomenon in the chromium-contaminated sites, causing undesirable secondary pollution. Microbial remediation is a promising technology to address the re-dissolution of chromium-containing slag after wet detoxification, and this article reviews the advances in this area. Firstly, the toxicity, current situation and conventional technologies for treating the chromium-containing slag were briefly summarized. The mechanisms of the inevitable re-dissolution of chromium-containing slag after wet detoxification were summarized. Three main mechanisms, namely bioreduction, biosorption and biomineralization, which are involved in the environmental-friendly and efficient microbial remediation technology, were reviewed. The variation of microbial species and the succession of microbial community during the bioremediation of chromium-contaminated sites were discussed. Finally, future research directions were prospected with the aim to develop long-term, stable and sustainable technologies for remediating the chromium-contaminated sites.


Subject(s)
Biodegradation, Environmental , Chromium/toxicity , Environmental Pollutants/toxicity
17.
Chinese Journal of Biotechnology ; (12): 3578-3590, 2021.
Article in Chinese | WPRIM | ID: wpr-921449

ABSTRACT

1,2,3-trichloropropane (TCP) is an industrially synthesized aliphatic chlorinated hydrocarbon and an intermediate product in the industrial production of epichlorohydrin, which can be used as a precursor for the manufacture of soil fumigant and organic solvents. Due to its biological toxicity, environmental persistence and strong environmental migration ability, 1,2,3-TCP is listed as an emerging organochlorine pollutant in the environment and regulated by many international organizations. Currently, the degradation of 1,2,3-TCP and the remediation of 1,2,3-TCP-contaminated sites receive great attention, but the degradation mechanism of 1,2,3-TCP has not been summarized in depth. This article discussed the origin of 1,2,3-TCP, its environmental impact and ecological effects, and the physical and chemical degradation techniques. This was followed by summarizing the degradation mechanisms of 1,2,3-TCP (e.g., aerobic co-biodegradation, anaerobic biodegradation). Specially, the pathways and mechanisms of microbial biodegradation and transformation of 1,2,3-TCP in anoxic environments (e.g., groundwater) were thoroughly reviewed. The feasibility of using 1,2,3-TCP as an electron acceptor by organohalide-respiring bacteria under anoxic conditions was predicted based on thermodynamic analysis. Last but not least, in situ bioremediation of 1,2,3-TCP contaminated sites was summarized, and prospects for future research were discussed.


Subject(s)
Biodegradation, Environmental , Environmental Restoration and Remediation , Hydrocarbons, Chlorinated , Propane/analogs & derivatives , Technology
18.
Chinese Journal of Biotechnology ; (12): 3565-3577, 2021.
Article in Chinese | WPRIM | ID: wpr-921448

ABSTRACT

The genus Dehalogenimonas (Dhgm) is a recently discovered taxonomic group within the class Dehalococcoidia of the phylum Chloroflexi. To date, Dhgm consists of three formally described species including Dehalogenimonas lykanthroporepellens, Dehalogenimonas alkenigignens and Dehalogenimonas formicexedens. All isolates of these three Dhgm species are obligate organohalide-respiring bacteria. They use hydrogen and formate as electron donors and chlorinated ethanes (e.g., 1,2,3-trichloropropane, 1,2-dichloropropane, 1,2-dichloroethane) as electron acceptors in energy-conserving reductive dechlorination reaction. Chlorinated ethanes are common groundwater contaminants in China. The unique metabolic capacities of Dhgm strains implicate it may play important roles in site remediation. The recently reported Dhgm sp. strain WBC-2 and 'Candidatus Dehalogenimonas etheniformans' strain GP are capable of dechlorinating certain chlorinated ethenes. More importantly, strain GP can completely detoxify the carcinogenic vinyl chloride (VC) to ethene. These findings expand the diversity of microorganisms involved in the respiratory VC reductive dechlorination and improve the understanding of Dhgm's ecological functions. Here, we summarize the advances in physiological and biochemical characteristics, ecological functions and genomic features of Dhgm, with the aim to develop effective and sustainable strategies to facilitate the bioremediation of chlorinated compounds contaminated sites.


Subject(s)
Anaerobiosis , Biodegradation, Environmental , Chloroflexi , Water Pollutants, Chemical
19.
Chinese Journal of Biotechnology ; (12): 3549-3564, 2021.
Article in Chinese | WPRIM | ID: wpr-921447

ABSTRACT

Bioremediation is regarded as one of the most promising methods for the remediation of the soil and groundwater contaminated with organic compounds, mainly due to its cost-effectiveness and environmental friendliness. Using VOSviewer and CiteSpace, we analyzed all publications in this area in core database of Web of Science from 1990 to 2020. The number of publications in this area showed an increasing trend worldwide. The country with the largest total number of publications was USA, followed by China and India. Since 2012, the number of annual publications of China exceeded USA and ranked the first. The top three journals which published papers in this area were Chemosphere, Environmental Science & Technology, and Science of the Total Environment. The Chinese Academy of Sciences published the largest number of papers among the research institutions globally, but the University of California in USA had the highest total citations and h-index. Bibliometric analysis indicated that it is important to develop biotechnologies of bioremediation coupled with chemical/physical remediation to overcome the challenge of low efficiency and long remediation duration associated with bioremediation. In addition, the bioremediation on the mixed contaminants, such as organic contaminants and heavy metals, or mixtures of different organic contaminants, is an important direction. Finally, the rapid development of microbiome technologies will further promote the exploration of mechanisms involved in bioremediation on the genetic and molecular level.


Subject(s)
Bibliometrics , Biodegradation, Environmental , Groundwater , Publications , Soil
20.
Chinese Journal of Biotechnology ; (12): 3535-3548, 2021.
Article in Chinese | WPRIM | ID: wpr-921446

ABSTRACT

Polycyclic aromatic hydrocarbons (PAHs) are a class of persistent pollutants that are widely distributed in the environment. Due to their stable structure and poor degradability, PAHs exhibit carcinogenic, teratogenic, and mutagenic toxicity to the ecological environment and organisms, thus increasing attentions have been paid to their removals and remediation. Green, safe and economical technologies are widely used in the bioremediation of PAHs-contaminated soil. This article summarizes the present status of PAHs pollution in soil of China from the aspects of origin, migration, fate, and pollution level. Meanwhile, the types of microorganisms and plants capable of degrading PAHs, as well as the underlying mechanisms, are summarized. The features of three major bioremediation technologies, i.e., microbial remediation, phytoremediation, and joint remediation, are compared. Analysis of the interaction mechanisms between plants and microorganisms, selection and cultivation of stress-resistant strains and plants, as well as safety and efficacy evaluation of practical applications, are expected to become future directions in this field.


Subject(s)
Biodegradation, Environmental , Polycyclic Aromatic Hydrocarbons/toxicity , Soil , Soil Microbiology , Soil Pollutants
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