Phytoremediation of cadmium-polluted soil by Chlorophytum laxum combined with chitosan-immobilized cadmium-resistant bacteria
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This study examined the performance of the chitosan-immobilized cadmium-resistant bacteria Arthrobacter sp. and Micrococcus sp. on cadmium phytoremediation by Chlorophytum laxum in cadmium-polluted soil. These immobilized cadmium-resistant bacteria can survive in cadmium-contaminated soil and significantly increased soil cadmium solubility, but the ability of chitosan-immobilized cells to increase cadmium solubility was lower than that of free cells. A pot experiment demonstrated that chitosan-immobilized Micrococcus sp. promoted the growth of C. laxum planted in cadmium-contaminated soil. A significant increase in the cadmium concentration in the roots and aboveground parts of C. laxum was found in plants inoculated with free and chitosan-immobilized cells of these bacteria. The performance of Arthrobacter sp. free cells to augment cadmium accumulation in C. laxum was a little bit better than that of chitosan-immobilized Arthrobacter sp., except at 9 weeks after planting. The phytoextraction coefficient, bioaccumulation factor, and translocation factor of C. laxum inoculated with free and chitosan-immobilized cells of cadmium-resistant bacteria were higher than those of the uninoculated control and increased with time. Our findings suggest that chitosan-immobilized cells can be exploited to enhance the efficiency of cadmium phytoremediation by C. laxum.
KeywordsCadmium-resistant bacteria Phytoremediation Chlorophytum Laxum Chitosan flakes Cell immobilization
This research was supported by the grant from Thailand Research Fund and Mahidol University (Grant no.RSA5780026). The authors thank V. Vanitshavit, A. Nisaitrongsrisug, N. Siribanchachai, and C. Sangthong for their valuable technical assistance.
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Conflict of interest
The authors declare that they have no conflict of interest.
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