强抗镉真菌月状旋孢腔菌对重金属的吸附作用

Metal Biosorption by Cochliobolus lunatus with High Cadmium Resistance

分离到的1株真菌月状旋孢腔菌(Cochliobolus lunatus)Cd7,可在2 000 mg L-1镉(Cd2+)液体培养液中存活,显示菌株具有较强的抗镉能力.吸附实验结果表明,菌丝球投加量为2 g L-1时,无论菌丝球灭活与否,菌株对Cd2+的吸附率随Cd2+浓度的升高而下降,吸附量随Cd2+浓度的升高而增加.当Cd2+浓度100 mg L-1以下时,灭活菌丝球对Cd2+的吸附量为活菌丝球的70%以上.菌丝球投加量为0.5-3.0 g L-1,菌株对Cd2+的吸附率随菌丝球投加量增加而增加,吸附量随菌丝球投加量的增加而急剧减少.pH 6.0、金属离子浓度为100 mg L-1时,菌丝球对单一Cd2+、Pb2+、Cu2+和Zn2+离子的平均吸附量顺序为:Cd2+>Zn2+>Cu2+>Pb2+.金属离子的共存抑制菌体对各离子的吸附,离子种类越多,抑制作用越明显.

A strain of Cochliobolus lunatus with high cadmium resistance was isolated and found to survive in liquid medium containing 2 000 mg L^-1 cadmium. Results showed with 2 g L^-1 mycelial pellets, the adsorption rates of Cd~＋ decreased with the increasing Cd concentration, but the adsorption quantity increased with the increase of Cd concentration. Inactivated myceliums could adsorb 70% more Cd than living ones when Cd was less than 100 mg Ll. When mycelial pellets was added in the range of 0.5-3.0 g L^-1, the adsorption rates of Cd^2＋ increased with the increasing mycelial pellets, but the adsorption quantity decreased sharply. Mycelial pellets showed different adsorption ability for different metals with the order of adsorption quantity of Cd^2＋ 〉 Zn^2＋ 〉 Cu^2＋ 〉 Pb^2＋ when single metal was in the concentration of 100 mg L^-1 at pH 6.0. Co-existence of different metals inhibited the absorption of metallic ions by mycelial pellets, the more ion species, the more obvious the inhibition. Fig 3, Tab 2, Ref23