College of Environmental Natural Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China; University of California - Davis, Davis, CA 95616, USA.
College of Environmental Natural Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou 310058, China.
J Hazard Mater. 2021 Jul 15;414:125494. doi: 10.1016/j.jhazmat.2021.125494. Epub 2021 Feb 24.
There is growing global interest in the bioremediation of cadmium (Cd) using combinations of biochar and microorganisms. However, the interactions among biochar, introduced and indigenous microorganisms remain unclear. Accordingly, a 90 day microcosm experiment was conducted to investigate this by adding Bacillus sp. K1 strain inoculated rice straw biochar (SBB) and magnetic straw biochar (MBB) into a Cd contaminated paddy soil from Hunan, China. All treatments were incubated aerobically (60% water holding capacity) or anaerobically for 90 d. During both soil incubations, Bacillus sp. K1 successfully colonized in soil with composites applications. Soil pH was significantly increased from acid to neutral, and available Cd decreased with the addition of both composites. The better remediation efficiency of MBB than SBB under anerobic conditions was attributed to the transformation of acetic acid-extractable Cd into the residual fraction, caused by Cd bonding with crystal FeO. The application of the two kinds of composites caused similar changes to both microbial communities. There was a slight decrease in indigenous microbial alpha diversity with the MBB aerobic application, while the total population number of bacteria was increased by 700%. Both the redundancy analysis and Mantel analyses indicated that pH and microbial biomass C contributed to the colonization of Bacillus sp. K1 with SBB under aerobic conditions, and with MBB under anerobic conditions, respectively. The research provides a new insight into interactive effects and investigates immobilization mechanisms involved of bacterial/biochar composites in anaerobic and aerobic soils.
利用生物炭和微生物组合修复镉（Cd）引起了全球越来越多的关注。然而，生物炭、引入和土著微生物之间的相互作用仍不清楚。因此，进行了为期 90 天的微宇宙实验，通过向来自中国湖南的 Cd 污染稻田土中添加接种了芽孢杆菌 K1 菌株的水稻秸秆生物炭（SBB）和磁性秸秆生物炭（MBB）来研究这一点。所有处理均在有氧（60%持水能力）或无氧条件下孵育 90 天。在两次土壤孵育过程中，芽孢杆菌 K1 在复合材料的应用中成功定植。土壤 pH 值从酸性升高到中性，并且随着两种复合材料的添加，可利用的 Cd 减少。在厌氧条件下，MBB 的修复效率优于 SBB，这归因于 Cd 与晶体 FeO 结合，将乙酸可提取的 Cd 转化为残留部分。两种复合材料的应用对微生物群落产生了相似的变化。MBB 有氧应用导致土著微生物 α 多样性略有下降，而细菌总数增加了 700%。冗余分析和 Mantel 分析均表明，pH 值和微生物生物量 C 分别有助于芽孢杆菌 K1 在有氧条件下与 SBB 定植，以及在厌氧条件下与 MBB 定植。该研究为细菌/生物炭复合材料在有氧和无氧土壤中的互作效应和固定化机制提供了新的见解。
