重金属抗性菌Bacillus cereus HQ-1对银离子的生物吸附-微沉淀成晶作用

发现1株对银离子有强吸附能力的蜡状芽孢杆菌HQ-1,研究了其对银离子的吸附特性及吸附机理.结果表明,菌体对银的吸附量可达91.75 mg/g,吸附过程符合Pseudo-second Order吸附动力学模型,相关系数高达0.999 9;吸附热力学很好地符合Freundlich吸附等温模型,相关系数为0.99;考察菌体浓度和温度对吸附的影响发现,菌体浓度增加有利于对银离子的吸附,温度对吸附影响较小;FTIR、SEM及EDAX实验结果表明吸附存在2种吸附机理,一为菌体表面一些含氮氧的基团对Ag⁺的络合作用,二为菌体分泌的胞外多糖等物质对Ag⁺的微沉淀成晶作用.

Biosorption of Ag+by Heavy Metals Hyperresistant Bacillus cereus Strain HQ-1

A newly isolated Bacillus cereus strain HQ-1 was found to possess high capability to absorb silver ions.The study showed that the biosorption process could be described well by pseudo-second-order kinetic model and Freundlich isotherm model.Higher cell concentration was favorable to the biosorption.Temperature's effect on the biosorption was not obvious.The oxygenous and nitrogenous functional groups on the cell wall played a very important role in the process of biosorption.Microdeposits were formed by interaction between silver ions and biopolymers from the cell wall(such as polysaccharides,proteins and some hydrolysis).