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| Preparation of bacterial heavy metal-immobilizing agents and their effects on reducing Cd and Pb uptake in lettuce |
| Received:April 24, 2021 |
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| KeyWord:medium optimization;microbial remediation agent;heavy metal-contaminated soil;biochar;lettuce;cadmium;lead |
| Author Name | Affiliation | E-mail | | KOU Fenglian | College of Life Sciences /Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China | | | ZHENG Jinwei | College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China | | | ZHENG Yingmin | College of Life Sciences /Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China | | | HE Zhuo | College of Life Sciences /Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China | | | SHENG Xiafang | College of Life Sciences /Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China | | | HE Linyan | College of Life Sciences /Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing Agricultural University, Nanjing 210095, China | helinyan7012@sina.com |
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| Abstract: |
| To ensure the safe production of vegetables and improve the ecological environment of farmland, it is necessary to expand the screening of safe and efficient heavy metal immobilization agents. In this study, single-factor experiments, Plackett-Burman design, steepest climbing test, and response surface analysis were used to optimize the spore formation medium of Bacillus megaterium H3. Sepiolite (C1)and biochar(C2)were selected as carriers to promote the survival of Bacillus megaterium H3. Field plot experiments were used to evaluate their effects on the growth and Cd and Pb contents in Italian lettuce(Lactuca sativa L.), and the characteristics of heavy metal- contaminated soils. The results showed that the optimized fermentation medium was molasses 3.8 g?L-1, soybean meal 9.25 g?L-1, calcium carbonate 9.5 g?L-1. The maximum number of spores was 5.9×109 CFU?mL-1, which was 156% higher than that in the initial fermentation medium. Biochar was a suitable carrier for the preparation of B. megaterium H3 microbial inoculants. B. megaterium H3 fermentation liquid, biochar, and solid agent C2 could increase the biomass and Vc content in Italian lettuce, reduce the content of Cd and Pb, and reduce the content of available Cd and Pb in the soils, while increasing the activities of urease and invertase. The solid agent C2 was found to be more effective than the B. megaterium H3 fermentation liquid and biochar single treatment. This study confirms that solid agent C2 can be a vital immobilization agent that can be used successfully to remediate heavy metal-polluted soils. |
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