Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao 266237, China.
College of Environment and Safety Engineering, Qingdao University of Science & Technology, Qingdao 266042, China.
J Hazard Mater. 2023 Sep 15;458:131921. doi: 10.1016/j.jhazmat.2023.131921. Epub 2023 Jun 22.
Phosphate solubilizing bacteria (PSB) has been considered an environmental-friendly phosphate fertilizer without cadmium (Cd) input into soils, but its possibility of Cd fixation in soil needs to be explored. Since direct inoculation results in a rapid decline of the population and activity, we immobilized Bacillus megaterium with maize straw biochar (B-PSB) and investigated its feasibility in remediating Cd-contaminated soil. Pot experiments showed that the application of B-PSB significantly ameliorated the growth of Brassica chinensis under Cd stress, with a fresh weight increased by 59.08% compared to the Cd-control. B-PSB reduced Cd accumulation in Brassica chinensis by 61.69%, and promoted the uptake of P and N by 134.97% and 98.71% respectively. Microbial community analysis showed B-PSB recruited more plant growth-promoting bacteria in near-rhizosphere soil, which provides a favorable microenvironment for both PSB and crops. Column leaching experiments verified that B-PSB achieved the dissolution of stable P while fixing Cd. Batch tests further revealed that biochar served as a successful carrier facilitating the growth of B. megaterium and Cd immobilization. Given the widespread Cd contamination in agricultural soils, our results indicate that B-PSB is a promising soil amendment to secure food safety.
解磷菌（PSB）被认为是一种环保型磷肥，不会向土壤中添加镉（Cd），但其在土壤中固定 Cd 的可能性仍需探讨。由于直接接种会导致种群和活性迅速下降，我们用玉米秸秆生物炭固定巨大芽孢杆菌（B-PSB），并研究了其在修复 Cd 污染土壤方面的可行性。盆栽实验表明，B-PSB 的应用显著改善了 Cd 胁迫下油菜的生长，鲜重比 Cd 对照增加了 59.08%。B-PSB 降低了油菜中 Cd 的积累，分别增加了 61.69%和 98.71%对 P 和 N 的吸收。微生物群落分析表明，B-PSB 在根际土壤中招募了更多的促生菌，为 PSB 和作物提供了有利的微环境。柱浸出实验验证了 B-PSB 实现了稳定 P 的溶解，同时固定了 Cd。批量实验进一步表明，生物炭作为一种成功的载体，促进了巨大芽孢杆菌的生长和 Cd 的固定。鉴于农业土壤中广泛存在的 Cd 污染，我们的结果表明，B-PSB 是一种有前途的土壤改良剂，可以确保食品安全。
