摘要
本文是为了解地衣芽孢杆菌富集镉的特性及机理,为该菌在镉污染治理中的应用提供理论基础。通过探究镉的初始浓度、培养时间、通气量、接种量对地衣芽孢杆菌富集Cd2+特性的影响,进一步利用红外光谱、圆二色光谱、扫描电镜-能谱仪和原子力显微镜探讨菌体富集Cd2+的机理。结果表明:在一定培养条件下,接菌量为6%,培养24 h,菌体对Cd2+的富集趋于平衡;100mL的细菌培养瓶中装40～50mL的液体培养基较为适宜;经驯化后的菌体对初始质量浓度为50～500mg·L-1的Cd2+都具有一定的耐受性和富集能力;菌体富集Cd2+后细胞壁及内部有大量颗粒物并检测出有镉元素,对Cd2+的富集主要依靠细胞壁上的羟基(-OH)、羰基(-CO-)、酰胺基(-CO-NH-)、磷酸基(-PO43-)等基团,而且重金属Cd2+还改变了菌体蛋白的空间构象。因此,本研究初步表明地衣芽孢杆菌抗镉和富集镉的机制是菌体表面的功能基团、表面分泌物聚集和富集Cd2+,以及将Cd2+运输到菌体内部进行富集。
Understanding the mechanism of Bacillus licheniformis resistance to cadmium will provide a theoretical basis for the application of the bacteria to cadmium pollution control. The effects of initial Cd2 ＋ concentration, bioaccumulation time, ventilation and inoculation amount on bioaccumulation ability of B. licheniformis were discussed. The mechanism of cadmium bioaccumulation by stain B. licheniformis was evaluated by infrared spectroscopy （FTIR）, circular dichroism （CD）, scanning electron microscopy-energy dispersive X-ray spectroscopy （SEM-EDX） and atomic force microscope （AFM）. It showed that bioaccumulation could reach a balance when the adsorption time and inoculation amount were 24 h and 6% , respectively. When the inoculation amount of the bacteria increased, the bioaccumulation rate was accelerated. Addition of 40mL to 50mL of liquid medium in 100mL bacterial culture flask could be the best choice; the domesticated bacteria can resist and accumulate Cd2＋ in the initial mass concentration of 50 -500mg· L^-1 The results indicated that much granular cadmium was precipitated on the cell wall and intracellular of bacteria based on the possible functional groups such as -OH, - CO , CO-NH - , and _pQ3-. Heavy metal Cd2＋ had changed the bacterial protein space conformation. All the results show some preliminary data for B. licheniformis resistance to cadmium and biosorption mechanism involving the function groups, secretion and enrichment of Cd2＋ on the bacterial surface and its transporting into bacteria.
出处
《核农学报》
CAS
CSCD
北大核心
2013年第11期1644-1651,共8页
Journal of Nuclear Agricultural Sciences
基金
海洋公益性行业科研专项(201105007)
关键词
地衣芽孢杆菌
镉
富集
机理
Bacillus licheniformis
Cadmium
Bioaccumulation
Mechanism
作者简介
孙静，女．主要从事食品科学与工程研究。E-mail：sj．binbin@163．com
通讯作者：苏秀榕，女，教授，主要从事食品科学与工程、生物化学与分子生物学研究。E-mail：suxiurong@nbu．edu．cn
