Two plant growth promoting bacterial Bacillus strains possess different mechanisms in adsorption and resistance to cadmium
Two plant growth promoting bacterial Bacillus strains possess different mechanisms in adsorption and resistance to cadmium
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两株植物促生芽孢杆菌具有不同的镉吸附和抗性机制
DOI：
10.1016/j.scitotenv.2020.140422
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发表时间：
2020-11-01
影响因子：
9.8
通讯作者：
Zhang, Dan
中科院分区：
文献类型：
--
作者：
Chi, Yaowei;Huang, Yueyuan;Zhang, Dan
微生物是一种很有前途的镉污染土壤或水体净化生物吸附剂，但其潜在的修复机制尚不清楚。本文研究了两株植物促生微生物（巨大芽孢杆菌NCT-2和副炭疽芽孢杆菌NT 1）对镉的吸附机理和吸附能力。批式吸附实验表明，生物吸附B的最佳条件为：megaterium NCT-2和B。在pH6.0、生物量1.0 g L-1、Cd ~（2+）初始浓度10 mg L-1和pH8.0、生物量1.0 g L-1、Cd ~（2+）初始浓度10 mg L-1的条件下，对拟炭疽菌NT 1的生长具有良好的促进作用。两种生物吸附剂对Cd 2+的吸附过程均符合准二级动力学模型，表明生物吸附剂对Cd 2+的吸附以化学吸附为主。B中吸附Cd ~（2+）的胞内积累部分。巨大芽孢杆菌NCT-2的表达显著高于B。paranthracis NT 1的镉耐受率分别为43.11%和3.25%，而对B的去除率分别为46.79%和20.45%;巨大NCT-2与B相比。副炭疽菌NT 1。SEM-EDS和FTIR分析表明，吸附过程中Cd 2+可能与吸附剂表面的-OH、-NH、-SO 3、CO和-COOH等配体发生了相互作用。qRT-PCR结果表明，B. megaterium NCT-2和B。副炭疽菌NT 1可能分别受基因cadA、zitB、khtT和bshA以及cadA、trkA、czcD和bshA调节。我们的研究结果表明，这两种生物吸附剂有潜力进一步用于开发镉修复技术，并可以提供深入了解镉的生物吸附机制。(c)2020 Elsevier B. V.保留所有权利。
Microorganisms are promising biosorbents for decontaminating cadmium-polluted soil or water systems, but the underlying remediation mechanisms are still unclear. In this study, the cadmium biosorption mechanisms and capabilities of plant growth-promoting microorganisms (Bacillus megaterium NCT-2 and Bacillus paranthracis NT1) were investigated. Batch biosorption experiments showed that the optimal biosorption conditions for B. megaterium NCT-2 and B. paranthracis NT1 were pH 6.0, a biomass dosage of 1.0 g L-1, and an initial Cd2+ concentration of 10 mg L-1, and pH 8.0, a biomass dosage of 1.0 g L-1, and an initial Cd2+ concentration of 10 mg L-1, respectively. The biosorption processes of both biosorbents were well described by the pseudosecond order kinetic model, which indicated that the biosorption of Cd2+ was mainly chemisorption. The intracellular accumulation portion of adsorbed Cd2+ in B. megaterium NCT-2 was much higher than in B. paranthracis NT1 (43.11% and 3.25%, respectively), which resulted in the lower cadmium tolerance (14 mg L-1 and 280 mg L-1, respectively) and higher cadmium removal efficiency (46.79% and 20.45%, respectively) of B. megaterium NCT-2 compared to B. paranthracis NT1. SEM-EDS and FTIR analysis suggested the probable interactions of Cd2+ with the biosorbent surface ligands, such as -OH, -NH, -SO3, C O and-COOH during surface adsorption. Results of qRT-PCR illustrated that the difference in cadmium resistant mechanism and adsorption performance between B. megaterium NCT-2 and B. paranthracis NT1 may be regulated by the genes cadA, zitB, khtT, and bshA and cadA, trkA, czcD, and bshA, respectively. Our results revealed that these two biosorbents have the potential for further use in the development of cadmium remediation technologies and could provide insight into the mechanisms of cadmium biosorption. (c) 2020 Elsevier B.V. All rights reserved.