地衣芽孢杆菌ATCC 9945A对亚碲酸盐的去除作用及机理

Tellurite removal and mechanism by Bacillus licheniformis ATCC 9945A

微生物在重金属离子固定、去除和解毒方面发挥着重要作用,在生物处理、生物修复、生物回收等方面具有巨大潜力.本文研究了一种常见土壤微生物地衣芽孢杆菌ATCC 9945A(Bacillus Licheniformis ATCC 9945A)对新兴污染物亚碲酸盐(Te(Ⅳ))的去除作用及机理.结果表明,ATCC 9945A对Te(Ⅳ)具有高水平抗性,在LB培养基中,最小抑菌浓度(MIC)为500 mg·L^(-1)Te(Ⅳ)(3.9 mmol·L^(-1)),而在培养基E中,MIC为450mg·L^(-1)Te(Ⅳ)(3.5 mmol·L^(-1)). Te(Ⅳ)浓度分别为5、10、25、50 mg·L^(-1)时,在LB培养基中,Te最大去除率分别为98.2%、97.7%、97.1%和89.7%,在培养基E中,Te最大去除率分别为98.6%、97.9%、98.7%和98.4%. ATCC 9945A对Te(Ⅳ)的吸附作用较小,分配系数K_(d)=(7.1±0.4) L·kg^(-1). ATCC9945A对Te(Ⅳ)的去除主要通过生物还原将高毒性、迁移能力强的可溶性Te(Ⅳ)还原为低毒性、运输能力差的单质六方晶型碲纳米颗粒.生物还原的机理为在细胞质内,Te(Ⅳ)与含有硫醇(SH—)的蛋白质、多肽等化合物进行Painter反应.

Microorganisms play an important role in the fixation,removal and detoxification of heavy metal ions,and they have great potential in biological treatment,bioremediation and biological recovery.In this paper,tellurite(Te(IV))removal and its mechanism by a common soil microorganism Bacillus licheniformis ATCC 9945A were studied.The results show that ATCC 9945A had high-level resistance to Te(IV).The minimal inhibitory concentration(MIC)was 500 mg·L^(-1) Te(IV)(3.9 mmol·L^(-1))in LB medium and 450 mg·L^(-1) Te(IV)(3.5 mmol·L^(-1))in medium E.At 5,10,25 and 50 mg·L^(-1) Te(IV),the Te maximum removal rates were 98.2%,97.7%,97.1%and 89.7%in LB medium,respectively,and 98.6%,97.9%,98.7%and 98.4%in medium E,respectively.The adsorption of Te(IV)by ATCC 9945A was low,and the distribution coefficient,K_(d),was(7.1±0.4)L·kg^(-1).The removal of Te(IV)by ATCC 9945A was mainly through the bioreduction of highly toxic and mobile soluble Te(IV)to low toxicity and poorly transportable elemental hexagonal tellurium nanoparticles.The bioreduction mechanism is that Te(IV)reacts with proteins,peptides and other compounds containing thiol(SH—)in the cytoplasm.