RESUMEN
This study prepared immobilized Alishewanella sp. WH16-1 using alginate and lotus seed pods as a matrix and investigated the effects of its immobilization on Cd2+ in a culture solution and in soil. Compared with the free WH16-1 strain, the immobilized WH16-1 strain possessed greater stability for long-term use and storage and higher removal ability for Cd2+ in the culture solution. A model of Cd2+ removal by the immobilized WH16-1 strain was proposed. The immobilized WH16-1 strain was incubated in the pot experiments of Cd-contaminated paddy soil for 120 days, and the pot experiments of Cd-contaminated paddy soil without the immobilized WH16-1 strain were used as a control. Compared with the control, the exchangeable and carbonate-bound Cd in the paddy soil incubated with the immobilized WH16-1 strain significantly decreased by 33.6% (Pâ¯<â¯0.05) and 17.36%, respectively, and the Cd concentrations in the rice significantly decreased by 78.31% (Pâ¯<â¯0.05). The results indicate that alginate-lotus seed pods can be used as excellent cost-effective cell carriers for the immobilization of Alishewanella sp. WH16-1 and that the immobilized WH16-1 strain may be applicable for the biological stabilization of Cd in Cd-contaminated paddy soil.
Asunto(s)
Alginatos/química , Alteromonadaceae/química , Cadmio/química , Células Inmovilizadas/química , Lotus/química , Contaminantes del Suelo/química , Restauración y Remediación Ambiental , Oryza , Semillas/químicaRESUMEN
Alishewanella sp. WH16-1 (= CCTCC M201507) is a facultative anaerobic, motile, Gram-negative, rod-shaped bacterium isolated from soil of a copper and iron mine. This strain efficiently reduces chromate (Cr(6+)) to the much less toxic Cr(3+). In addition, it reduces sulfate (SO4 (2-)) to S(2-). The S(2-) could react with Cd(2+) to generate precipitated CdS. Thus, strain WH16-1 shows a great potential to bioremediate Cr and Cd contaimination. Here we describe the features of this organism, together with the draft genome and comparative genomic results among strain WH16-1 and other Alishewanella strains. The genome comprises 3,488,867 bp, 50.4 % G + C content, 3,132 protein-coding genes and 80 RNA genes. Both putative chromate- and sulfate-reducing genes are identified.