【摘要】 以黑曲霉(Aspergillus niger)为实验菌株,探讨不同pH值、重金属离子初始浓度、孢子液接种量和重金属离子共存对菌体生长量和富集能力的影响。结果表明:Cu(Ⅱ)和Zn(Ⅱ)对黑曲霉的最低抑菌浓度分别为250、700mg·L-1;菌株最佳生长和富集条件为pH5.0、孢子液体积1mL,黑曲霉对Cu(Ⅱ)和Zn(Ⅱ)的富集分别在4d和5d达到平衡。在重金属共存系统中,Cu(Ⅱ)/Zn(Ⅱ)浓度越高,黑曲霉对Cu(Ⅱ)/Zn(Ⅱ)富集能力越强;Cu(Ⅱ)和Zn(Ⅱ)的富集量分别在其浓度为150、250mg·L-1时达到最大(8.89、22.80mg·g-1)。采用扫描和透射电镜观察富集前后菌体表面形态和内部结构变化,表明菌体生长受重金属毒害作用可能破坏菌丝表面结构,A.niger富集Cu(Ⅱ)和Zn(Ⅱ)由表面吸附和胞内富集两部分组成,Zn(Ⅱ)作用下菌丝的完整性较好,菌株对Zn(Ⅱ)具有较强的抗性和适应能力。更多还原

【Abstract】 Aspergillus niger is the most widespread saprophytic fungus in the terrestrial environment, which is one of the most suitable candi- date for removing heavy metal ions. Effects of pH, initial Cu(Ⅱ)and Zn(Ⅱ)concentration, spore inoculum amount and co-ions in solution on the growth and bioaccumulation efficiency of heavy metal by A. niger were investigated. Results showed that the minimal inhibitory con- centration of Cu(Ⅱ)and Zn(Ⅱ)for A. niger growth were 250 mg·L-1 and 700 mg·L-1, respectively. The optimum conditions for growth and accumulation of A. niger were pH5.0 and 1 mL of spore inoculum amount. Bioaccumulation equilibriums of Cu(Ⅱ)and Zn(Ⅱ)in A. niger were reached in 4 d and 5 d. In the binary Cu(Ⅱ)+Zn(Ⅱ)system, the higher the concentration of Cu(Ⅱ)/Zn(Ⅱ)ions, the more accumu- lation of Cu(Ⅱ)/Zn(Ⅱ)ions by A. niger. The maximum accumulation capacities of Cu(Ⅱ)and Zn(Ⅱ)in A. niger were 8.89 mg·g-1 and 22.80 mg·g-1 at initial concentrations of 150 mg·L-1 and 250 mg·L-1, respectively. Furthermore, the changes of surface morphology and inter- nal structure of A. niger were obtained by scanning electron micrograph and transmission electron microscope. This suggested that the surface structure of mycelium might be destroyed by the heavy metal toxicity, and the bioaccumulation of A. niger included extracellular and intra- cellular biosorption. The stain held high tolerance and adaptive abilities of Zn(Ⅱ)for its mycelium relatively integrity.更多还原