School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan 621010, China; School of Environment and Energy, South China University of Technology, Guangzhou 510006, China.
School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan 621010, China; Analytical Testing Center, Sichuan University, Chengdu 610064, China.
J Hazard Mater. 2022 Aug 15;436:129147. doi: 10.1016/j.jhazmat.2022.129147. Epub 2022 May 13.
Microbial remediation of heavy metals in soil has been widely studied. However, bioremediation efficiency is limited in practical applications because of nutritional deficiency, low efficiency, and competition with indigenous microorganisms. Herein, we prepared a biochar-based microbial agent (BMA) by immobilizing the microbial agent (MA, containing Bacillus subtilis, Bacillus cereus, and Citrobacter sp.) on biochar for the remediation of U and Cd in soil. The results showed that BMA increased soil organic matter, cation exchange capacity, and fluorescein diacetate hydrolysis activity and dehydrogenase activity by 58.7%, 38.2%, 42.9%, and 51.1%. The availability of U and Cd were significantly decreased by 67.4% and 54.2% in BMA amended soil, thereby reducing their accumulation in vegetables. BMA greatly promoted vegetable growth. Additionally, BMA significantly altered the structure and function of rhizosphere soil microbial communities. Coincidently, more abundant ecologically beneficial bacteria like Nitrospira, Nitrosomonas, Lysobacter, and Bacillus were observed, whereas plant pathogenic fungi like Fusarium and Alternaria reduced in BMA amended soil. The network analysis revealed that BMA amendment increased the tightness and complexity of microbial communities. Importantly, the compatibility of niches and microbial species within co-occurrence network was enhanced after BMA addition. These findings provide a promising strategy for suppressing heavy metal accumulation in vegetables and promoting their growth.
土壤中重金属的微生物修复已经得到了广泛的研究。然而，由于营养缺乏、效率低下以及与土著微生物的竞争，生物修复效率在实际应用中受到限制。在此，我们通过将微生物剂（MA，包含枯草芽孢杆菌、蜡样芽孢杆菌和柠檬酸杆菌）固定在生物炭上来制备基于生物炭的微生物剂（BMA），以修复土壤中的 U 和 Cd。结果表明，BMA 增加了土壤有机质、阳离子交换容量、荧光素二乙酸水解活性和脱氢酶活性，分别提高了 58.7%、38.2%、42.9%和 51.1%。BMA 处理的土壤中 U 和 Cd 的有效性分别显著降低了 67.4%和 54.2%，从而减少了它们在蔬菜中的积累。BMA 显著促进了蔬菜的生长。此外，BMA 还显著改变了根际土壤微生物群落的结构和功能。同时，观察到更多丰富的生态有益细菌，如硝化螺菌、亚硝化单胞菌、蜡状芽孢杆菌和芽孢杆菌，而在 BMA 处理的土壤中，植物病原菌真菌如镰刀菌和链格孢菌减少了。网络分析表明，BMA 处理增加了微生物群落的紧密性和复杂性。重要的是，在添加 BMA 后，共现网络中生态位和微生物物种的兼容性得到了增强。这些发现为抑制蔬菜中重金属积累和促进其生长提供了一种有前景的策略。
