以黄孢原毛平革菌为研究对象,探讨了白腐真菌胞外聚合物及其对白腐真菌吸附Pb2+的影响.通过培养实验,研究了白腐真菌胞外聚合物(extracellular polymeric substances,EPS)的产量、组成以及对Pb2+吸附量的影响,并采用带能谱仪的环境扫描电镜(ESEM-EDX)表征了胞外聚合物提取前后及Pb2+吸附前后白腐真菌菌体表面的变化.结果表明,在振荡培养113 h后,获得最大的EPS量125.5 mg/L,其中糖类占46.6%~54.3%,蛋白质占31.2%~35.1%.对照吸附实验显示提取胞外聚合物后,白腐真菌对Pb2+的吸附量明显降低,最小降低2.12 mg/g(113 h),最大降低7.73 mg/g(41 h).环境扫描电镜(ESEM)结果显示,EPS提取前后,白腐真菌菌体表面结构发生了改变.在吸附Pb2+后,菌体表面产生了球状含Pb颗粒物.此研究对进一步深入探讨重金属生物吸附机制具有重要意义.
The extracellular polymeric substances(EPS) of P.chrysosporium and their effects on Pb2 + biosorption were studied.The product,composition of EPS and the effects on Pb2 + biosorption capacity were investigated in lab via flask experiments.The surface changes of mycelium before and after EPS extraction,before and after Pb2 + adsorption were researched by environment scanning electron microscope with energy-dispersive X-ray analysis(ESEM-EDX).Results showed that at 113 h,the maximum yield of EPS was 125.5 mg /L,which contained 46.6%-54.3% of sugar and 31.2%-35.1% of protein.The results of control test after EPS extraction displayed a decrease of biosorption capacity of Pb2 + among 2.12 mg /g(113 h)-7.73 mg /g(41 h).The results of environment scanning electron microscope(ESEM) showed that the EPS extraction affected the cell wall of white-rot fungus and the Pb-contained globular particle after Pb2 + uptake,which was very useful for further study on heavy metal biosorption mechanism.