【摘要】 于1993年5月由南京大学藻类培养室提供极大螺旋藻藻种，用Zarrouk培养基培养后，用活藻体和甲醛杀死的藻体分别进行吸附实验；过滤出的藻体置于6×10－3g／L左右浓度的Co2+，Ni2+，Cu2+，Zn2+离子混合液中。结果显示，死、活藻体都具有相似的吸附能力，对Co2+，Ni2+，Zn2+的富积大于203倍，对Cu2+的富积大于185倍；用热水提取、DEAE-纤维素D-23柱和SephadexG－200柱纯化后，获得了纯细胞外壁多糖，其分子量为52kD。将该糖溶液盛在透析袋内，并置于4种离子混合液中进行吸附实验，结果显示，核糖对Co2+，Ni2+，Cu2+，Zn2+的富积倍数分别达1744，1644，1340，1750。藻体和多糖对Co2+，Ni2+，Zn2+的吸附都高于对Cu2+的吸附。比较藻体与多糖对4种离子的吸附结果可见，藻体对离子的吸附主要是多糖的作用；多糖的红外光谱显示，金属离子改变OH和CO－NH的吸收峰，表明这两种基团与金属离子发生了络合作用；对Cu2+的络合滴定测定表明，Cu2+与多糖的结合度为0．40。更多还原

【Abstract】 The accumulation of heavy metals by an intact alga, Spirulina maxima, and itsextracelullar polysaccharide (EPS) was studied. The alga was supplied by Algas Culture Laboratoryof Nanjing University in may 1995. The culbe medium was Zarrouk medium. Living algae anddead algae killed by formol were obtained by filtaion and mixed with a Co2+, Ni2+, Cu2+, Zn2+complex solution (pH = 5.0), which was CoCl2, NiSO4, CuSO4, and ZnSO4 salts. Every metal ioncontent in the solution was around 6×10.3 g / L. After mixing with the metal ion solution for 30then,the algae were filtered out and the concentrations of the four ions in the solution were measured.The results show tha S. maxima strongly adsorb the four ions; the quantities of CO2+, Ni2+, Zn2+adsothed in the algae were more than 203 times higher than in the initial solution, with that of Cu2+being more than 185 times. The abilities of the algae adsorpting Co2+, Ni2+, Zn2+ were higher thanCu2+. There is no significant differences between the living and the dead(Tab. 1) EPS of S maximawas extracted by hot water and separated by a DEAE-Cellular D-23 colunm and s Sephadex G-200column. Its molecular weight was 52kD measured by high liquld chromatogram. To measure theability of EPS adsorpting metal ions, an EPS solution placed in a dialyzer was put into Co2, Ni2+,Cu2+, Zn2+ ions complex solution. Each of the four ions in the solution had a concentration ofaround 6×10-3 g/L. The results show that the EPS strongly adsorbs the ions; it concentrated Co2+,Ni2+, Cu2+, Zn2+ ions for 1 774, 1 644, 1 340 and 1 750 times respectively (Tab.2). The EPS andthe intact algae adsorbed more Co2+, Ni2+, Zn2+ than Cu2+. Comparing the adsorption of intactalgae with the EPS, it is suggested that the adsorption of intact algas is mainly caused by theadsorption of EPS.Infrared spectra of EPS and the EPS combined with different metal ions show that metal ionscan chane the key vibrahon of oH (3 422, 1416,1230) nd CO-NH (1622) (Tab.3). Thus, theadsorption of metal ions by the EPS is due to OH and Co-NH coordinating the metals.The cappcity of EPS combining Cu2+ was measured using the method of ion-selective electrode.A curve of Cu2+ titrating EPS was obtained (Fig. 1). At the equilibrium point the titrate was 0.40.This obeervation means tha each single sugar molecular of EPS can combine 0.40 molecular Cu2+.更多还原