Deciphering the bacterial microbiome in response to long-term mercury contaminated soil.

Hg contaminated soils are of concern due to the toxic effects on soil microbes. Currently, the adaptation of bacterial community to long-term Hg contamination remains largely unknown. Here, we assessed the effects of Hg contaminated soils on the bacterial communities under controlled conditions using 16S rRNA gene amplicon sequencing.

Effects of Pseudomonas alkylphenolica KL28 on immobilization of Hg in soil and accumulation of Hg in cultivated plant.

Objective: The available content of mercury (Hg) in farmland soil is directly related to the safety of agricultural products. Meanwhile, humans may accumulate high concentrations of Hg through the food chain, resulting in health damage. Regarding the remediation technologies of Hg-contaminated soil, research and development is mainly concentrated on the immobilisation of Hg in soil and efficient extraction by accumulators.

Characterization of cadmium-resistant rhizobacteria and their promotion effects on Brassica napus growth and cadmium uptake.

Excessive cadmium (Cd) accumulation in soil can adversely affect plants, animals, microbes, and humans; therefore, novel and uncharacterized Cd-resistant plant-growth-promoting rhizobacteria (PGPR) are required to address this issue. In the paper, 13 bacteria were screened, their partial 16S rRNA sequences determined, and the isolates, respectively, clustered into Curtobacterium (7), Chryseobacterium (4), Cupriavidus (1), and Sphingomonas (1). Evaluation of PGP traits, including indole-3-acetic acid (IAA) production, 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity, siderophore secretion, and cyanhydric acid production, identified Cupriavidus necator GX_5, Sphingomonas sp.

Adsorption of cadmium by live and dead biomass of plant growth-promoting rhizobacteria.

Plant growth-promoting rhizobacteria (PGPR) have been extensively investigated in combination remediation with plants in heavy metal contaminated soil. However, being biosorbent, few studies of live and dead cells of PGPR have been undertaken. Meanwhile, the application of live or dead biomass for the removal of heavy metals continues to be debated.

Biosorption and bioaccumulation characteristics of cadmium by plant growth-promoting rhizobacteria.

Plant growth-promoting rhizobacteria (PGPR) not only promote growth and heavy metal uptake by plants but are promising biosorbents for heavy metals remediation. However, there exist arguments over whether extracellular adsorption (biosorption) or intracellular accumulation (bioaccumulation) play dominant roles in Cd(ii) adsorption. Therefore, three cadmium-resistant PGPR, GX_5, sp.

Effect of chitosan on the available contents and vertical distribution of Cu2+ and Cd2+ in different textural soils.

Chitosan, an environment-friendly biopolymer, has been adopted to remedy contaminated soils by heavy metals of Cu(2+) and Cd(2+). Experimental results demonstrated that, within the first 7d, available Cu(2+) and Cd(2+) contents in three textural soils (clay, loam, and sandy soil) decreased significantly after chitosan application. Moreover, the available Cu(2+) and Cd(2+) contents in soil layers of 14-16 cm and 24-26 cm were significantly reduced than that in 4-6 cm after 7d of chitosan application.

Effect of organic substrates on available elemental contents in nutrient solution.

In this paper, the changes of available elemental contents in the nutrient solution extracts of organic substrates (peat moss, charred rice husk, chicken manure, sawdust, turfgrass clipping and weathered coal) were studied and compared with that in the water extracts. Results showed that available elemental contents in the nutrient solution extracts are significantly different between organic substrates, whereas ionic concentrations are basically under steady condition after treatment for 36-108 h. Ionic contents in the nutrient solution extracts are not equal to the value of adding ionic concentrations in the supplied nutrient solution to that in the water extract.