Cadmium Pollution Impact on the Bacterial Community Structure of Arable Soil and the Isolation of the Cadmium Resistant Bacteria

Abstract

Microorganisms play an important role in the remediation of cadmium pollution in the soil and their diversity can be affected by cadmium. In this study, the bacterial community in arable soil samples collected from two near geographical sites, with different degrees of cadmium pollution at three different seasons, were characterized using Illumina MiSeq sequencing. The result showed that cadmium is an important factor to affect the bacterial diversity and the microbial communities in the high cadmium polluted area (the site H) had significant differences compared with low cadmium polluted area (the site L). Especially, higher concentrations of Cd significantly increased the abundance of Proteobacteria and Gemmatimonas whereas decreased the abundance of Nitrospirae. Moreover, 42 Cd-resistant bacteria were isolated from six soil samples and evaluated for potential application in Cd bioremediation. Based on their Cd-MIC [minimum inhibitory concentration (MIC) of Cd2+], Cd2+ removal rate and 16S rDNA gene sequence analyses, three Burkholderia sp. strains (ha-1, hj-2, and ho-3) showed very high tolerance to Cd (5, 5, and 6 mM) and exhibited high Cd2+ removal rate (81.78, 79.37, and 63.05%), six Bacillus sp. strains (151-5,151-6,151-13, 151-20, and 151-21) showed moderate tolerance to Cd (0.8, 0.4, 0.8, 0.4, 0.6, and 0.4 mM) but high Cd2+ removal rate (84.78, 90.14, 82.82, 82.39, 81.79, and 84.17%). Those results indicated that Burkholderia sp. belonging to the phylum Proteobacteria and Bacillus sp. belonging to the phylum Firmicutes have developed a resistance for cadmium and may play an important role in Cd-contaminated soils. Our study provided baseline data for bacterial communities in cadmium polluted soils and concluded that Cd-resistant bacteria have potential for bioremediation of Cd-contaminated soils.

Bacteria-loaded biochar for the immobilization of cadmium in a natural alkaline polluted soil

“…Soil microorganisms are important components of soil metabolism (Zhao et al, 2021). Alteration of the bacterial community structure is involved in the circulation and ow of the soil ecosystem (Yu et al, 2021). In this study, a notable change in the bacterial community occurred after the addition of bacteria-loaded biochar, which might correlate with the reduction in available Cd in soil.…”

Resistance to Heavy Metals of Actinobacteria Isolated From the Biological Fouling of Shellfish and Mussels of the Odesa Gulf of the Black Sea

“…Така чутливість до кадмію, на нашу думку, є підтвердження його високої токсичності і свідченням відсутності у досліджених штамів актинобактерій механізмів стійкості до цього важкого металу. З урахуванням отриманих даних, актинобактерії, як одні із членів морського мікробіому, можна розглядати як біоіндикатори забруднення морської екосистеми кадмієм, оскільки вони набагато чутливіші до стресу, ніж макроорганізми і досить швидко реагують на відповідні зміни [24].…”