Immobilization of Cd Using Mixed Enterobacter and Comamonas Bacterial Reagents in Pot Experiments with Brassica rapa L.

Abstract

Enterobacter sp. A11 and Comamonas sp. A23 were isolated and identified. Coculturing these two strains with Cd­(II) led to the production of biofilm, H2S, and succinic acid (SA), and Cd­(II) was adsorbed by cells and formed CdS precipitates. After centrifugation, 97% Cd­(II) was removed from the coculture. Proteomic and metabolomic analyses of the cocultured bacteria revealed that H2S and SA production pathways, metal transportation, and TCA cycle were active under Cd­(II) stress. In vitro addition of SA enhanced the production of H2S and biofilm formation and Cd­(II) adsorption. Two-season greenhouse pot experiments with Brassica rapa L. were performed with and without the coculture bacteria. Compared with the control, the average Cd amounts of the two-season pot experiments of the aboveground plants were decreased by 71.3%, 62.8%, and 38.6%, and the nonbioavailable and immobilized Cd in the soils were increased by 211.8%, 213.4%, and 116.7%, for low-, medium-, and high- Cd-spiked soils, respectively. The two strains survived well in soil during plant growth using plate counting, quantitative real-time PCR, and metagenomics analysis. Our results indicate that the combination of Enterobacter and Comamonas strains with the production of H2S and biofilm are important effectors for the highly efficient immobilization of Cd.

Varying Efficacies of Fenton's Oxidation Treatment on Pharmaceutical Industry Effluents of Contrasting Viscosity Profiles

“…The generated hydroxyl radicals initiate in situ oxidation by extracting hydrogen from the organic pollutant. This sets off a chain reaction by this newly formed organic radical with dissolved ferric ions and H 2 O 2 , and is further oxidized: [ 33 ] …”

“…The generated hydroxyl radicals initiate in situ oxidation by extracting hydrogen from the organic pollutant. This sets off a chain reaction by this newly formed organic radical with dissolved ferric ions and H 2 O 2 , and is further oxidized: [33] RH…”

Effective Heterogeneous Fenton‐Like degradation of Malachite Green Dye Using the Core‐Shell Fe3O4@SiO2Nano‐Catalyst

“…Moreover, it can generate large amounts of iron sludge. [14,15] Therefore, the application of heterogenous fenton catalysts instead of the traditional fenton catalyst is becoming increasing popular as they can easily overcome these drawbacks. [16,17] Among the several heterogenous fenton-like catalysts studied in the literature, Fe 3 O 4 could spontaneously catalyze the hydrogen peroxide under various experimental conditions.…”

“…However, their successful implementation depends several factors like maintaining an acidic pH of 3 and requiring stochiometric amount of the Fe 2+ ions. Moreover, it can generate large amounts of iron sludge [14,15] . Therefore, the application of heterogenous fenton catalysts instead of the traditional fenton catalyst is becoming increasing popular as they can easily overcome these drawbacks [16,17] …”

Sonophotocatalytic Degradation of Pollutants by ZnO‐Based Catalysts: A Review

“…The second group consists of materials that perform oxidation in the environment alone or combined with each other through the production of hydroxyl radicals. These processes are also called advanced oxidation processesand they are much more efficient than the previous group [20,21] …”