scholarly journals Influence of Root Exudates on the Bacterial Degradation of Chlorobenzoic Acids

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Blanka Vrchotová ◽  
Petra Lovecká ◽  
Milena Dražková ◽  
Martina Macková ◽  
Tomas Macek

Degradation of chlorobenzoic acids (e.g., products of microbial degradation of PCB) by strains of microorganisms isolated from PCB contaminated soils was assessed. From seven bulk-soil isolates two strains unique in ability to degrade a wider range of chlorobenzoic acids than others were selected, individually and even in a complex mixture of 11 different chlorobenzoic acids. Such a feature is lacking in most tested degraders. To investigate the influence of vegetation on chlorobenzoic acids degraders, root exudates of two plant species known for supporting PCB degradation in soil were tested. While with individual chlorobenzoic acids the presence of plant exudates leads to a decrease of degradation yield, in case of a mixture of chlorobenzoic acids either a change in bacterial degradation specificity, associated with 3- and 4-chlorobenzoic acid, or an extension of the spectrum of degraded chlorobenzoic acids was observed.

2005 ◽  
Vol 60 (3-4) ◽  
pp. 331-339 ◽  
Author(s):  
Clayton L. Rugha ◽  
Endang Susilawati ◽  
Alexandra N. Kravchenko ◽  
John C. Thomas

Abstract Root-microbe interactions are considered to be the primary process of polyaromatic hydrocarbon (PAH) phytoremediation, since bacterial degradation has been shown to be the dominant pathway for environmental PAH dissipation. However, the precise mechanisms driving PAH rhizostimulation symbiosis remain largely unresolved. In this study, we assessed PAH degrading bacterial abundance in contaminated soils planted with 18 different native Michigan plant species. Phenanthrene metabolism assays suggested that each plant species differentially influenced the relative abundance of PAH biodegraders, though they generally were observed to increase heterotrophic and biodegradative cell numbers relative to unplanted soils. Further study of > 1800 phenanthrene degrading isolates indicated that most of the tested plant species stimulated biodegradation of a broader range of PAH compounds relative to the unplanted soil bacterial consortia. These observations suggest that a principal contribution of planted systems for PAH bioremediation may be via expanded metabolic range of the rhizosphere bacterial community.


2021 ◽  
Vol 11 (4) ◽  
pp. 1769
Author(s):  
María Noelia Jiménez ◽  
Gianluigi Bacchetta ◽  
Francisco Bruno Navarro ◽  
Mauro Casti ◽  
Emilia Fernández-Ondoño

The use of plant species to stabilize and accumulate trace elements in contaminated soils is considered of great usefulness given the difficulty of decontaminating large areas subjected to mining for long periods. In this work, the bioaccumulation of trace elements is studied by relating the concentrations in leaves and roots of three plants of Mediterranean distribution (Dittrichia viscosa, Cistus salviifolius, Euphorbia pithyusa subsp. cupanii) with the concentrations of trace elements in contaminated and uncontaminated soils. Furthermore, in the case of D. viscosa, to know the concentration of each element by biomass, the pool of trace elements was determined both in the aerial part and in the roots. The bioaccumulation factor was not high enough in any of the species studied to be considered as phytoextractors. However, species like the ones studied in this work that live on soils with a wide range of concentration of trace elements and that develop a considerable biomass could be considered for stabilization of contaminated soils. The plant species studied in this work are good candidates for gentle-remediation options in the polluted Mediterranean.


2021 ◽  
Vol 232 (7) ◽  
Author(s):  
N. Matanzas ◽  
E. Afif ◽  
T. E. Díaz ◽  
J. R. Gallego

AbstractPhytomanagement techniques using native species allow the recovery of contaminated soils at low cost and circumvent the ecological risks associated with the use of non-native species. In this context, a paradigmatic brownfield megasite highly contaminated by As and Pb was sampled in order to analyze soil–plant interactions and identify plant species with phytoremediation potential. A survey was first carried out in a 20-ha area to obtain an inventory of species growing spontaneously throughout the site. We then performed another survey in the most polluted sub-area (1 ha) within the site. Pseudototal concentrations of contaminants in the soil, aerial parts of the plants, and roots were measured by ICP-MS. A detailed habitat classification was done, and a specific index of coverage was applied by means of a 1-year quadrat study in various sampling stations. Results converged in the selection of six herbaceous species (Dysphania botrys, Lotus corniculatus, Lotus hispidus, Plantago lanceolata, Trifolium repens, Medicago lupulina). All of these plants are fast-growing, thereby making them suitable for use in phytostabilization strategies. Furthermore, they are all easy to grow and propagate and are generally self-sustaining. All six plants showed accumulation factors below 1, thus revealing them as pseudomethallophytes and excluders. However, L. hispidus and M. lupulina showed translocation capacity and are considered worthy of further study.


1995 ◽  
Vol 29 (6) ◽  
pp. 1615-1621 ◽  
Author(s):  
Claude-Henri. ChaIneau ◽  
Jean-Louis. Morel ◽  
Jean. Oudot

Agronomy ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1750
Author(s):  
María Pilar Bernal ◽  
Donatella Grippi ◽  
Rafael Clemente

Phytomanagement of trace element-contaminated soils combines sustainable soil remediation with the use of plant biomass for different applications. Consequently, phytostabilization using plant species useful for bioenergy production has recently received increasing attention. However, the water requirement of most of these species is a limitation for their use under Mediterranean climatic conditions. In this work, eight plant species growing naturally in mine soils contaminated by trace elements were evaluated for their use as bioenergy crops using thermochemical (combustion) and biochemical (anaerobic digestion) methods. The higher heating values of the biomass of the plants studied were all within a narrow range (16.03–18.75 MJ kg−1), while their biochemical methane potentials ranged from 86.0 to 227.4 mL CH4 (g VS)−1. The anaerobic degradation was not influenced by the presence of trace elements in the plants, but the mineral content (mainly Na) negatively affected the potential thermal energy released by combustion (HHV). The highest annual energy yields from biogas or combustion could be obtained by the cultivation of Phragmites australis and Arundo donax, followed by Piptatherum miliaceum. Both options can be considered to be suitable final destinations for the biomass obtained in the phytostabilization of trace element-contaminated soils and may contribute to the implementation of these remediation techniques in Mediterranean areas.


2021 ◽  
Author(s):  
Wenyin Wang ◽  
Tianhua Jia ◽  
Tianyun Qi ◽  
Shanshan Li ◽  
Degen A.Allan ◽  
...  

Abstract Background The interaction between rhizosphere microorganisms and rhizosphere exudates is considered a ‘novel weapon’ for poisonous plants’ colonization, but the relationship between them in facilitating the expansion of poisonous plants in degraded or barren land is poorly understood. We examined this relationship in different degradation levels of alpine grasslands on the Tibetan plateau (3,700 m a.s.l) by determining the composition of root exudates, soil physical and chemical properties, rhizosphere microbial diversity and carbon metabolism of the main poisonous and non-poisonous plant species. Results Soil nutrients, including total organic carbon, total nitrogen and available phosphorous, diversity of microorganisms and microbial carbon metabolism were greater in the rhizosphere of poisonous than in non-poisonous plant species (P < 0.05). The distribution of bacteria and root exudates were plant species specific. Soil microbial communities were affected by habitat and plant species in degraded grassland, and more so for bacteria than fungi. The cell growth and death pathway for the poisonous species Ligularia virgaurea was greater than for other poisonous species (P < 0.05), and the difference increased with an increase in grassland degradation and a decrease in soil nutrients (P < 0.05), which could explain how L. virgaurea became the dominant poisonous species in degraded alpine grassland. The roots of L. virgaurea exudated such compounds as alkaloids, lupinic acid, terpenes, artemisinin, and coumarin, which were correlated positively with different bacteria in different habitats. Conclusion It was concluded that poisonous plant species adapted to degraded grassland through the interaction of root exudates and rhizosphere microorganisms, which facilitated their expansion in degraded alpine grassland.


2020 ◽  
Vol 8 (4) ◽  
pp. 473 ◽  
Author(s):  
Yaohua Huang ◽  
Ziqiu Lin ◽  
Wenping Zhang ◽  
Shimei Pang ◽  
Pankaj Bhatt ◽  
...  

Persistent use of the insecticide D-cyphenothrin has resulted in heavy environmental contamination and public concern. However, microbial degradation of D-cyphenothrin has never been investigated and the mechanism remains unknown. During this study, for the first time, an efficient D-cyphenothrin-degrading bacterial strain Staphylococcus succinus HLJ-10 was identified. Response surface methodology was successfully employed by using Box-Behnken design to optimize the culture conditions. At optimized conditions, over 90% degradation of D-cyphenothrin (50 mg·L−1) was achieved in a mineral salt medium within 7 d. Kinetics analysis revealed that its half-life was reduced by 61.2 d, in comparison with the uninoculated control. Eight intermediate metabolites were detected in the biodegradation pathway of D-cyphenothrin including cis-D-cyphenothrin, trans-D-cyphenothrin, 3-phenoxybenzaldehyde, α-hydroxy-3-phenoxy-benzeneacetonitrile, trans-2,2-dimethyl-3-propenyl-cyclopropanol, 2,2-dimethyl-3-propenyl-cyclopropionic acid, trans-2,2-dimethyl-3-propenyl-cyclopropionaldehyde, and 1,2-benzenedicarboxylic acid, dipropyl ester. This is the first report about the degradation of D-cyphenothrin through cleavage of carboxylester linkage and diaryl bond. In addition to degradation of D-cyphenothrin, strain HLJ-10 effectively degraded a wide range of synthetic pyrethroids including permethrin, tetramethrin, bifenthrin, allethrin, and chlorempenthrin, which are also widely used insecticides with environmental contamination problems. Bioaugmentation of D-cyphenothrin-contaminated soils with strain HLJ-10 substantially enhanced its degradation and over 72% of D-phenothrin was removed from soils within 40 d. These findings unveil the biochemical basis of a highly efficient D-cyphenothrin-degrading bacterial isolate and provide potent agents for eliminating environmental residues of pyrethroids.


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