黑曲霉菌株TLSF2对水中Cu、Cd的吸附机理探讨

黑曲霉(Aspergillus niger)菌株TLSF2是1株新发现的耐重金属真菌,为深入了解该菌株对水中Cu、Cd的吸附机理,借助原子分光光度法,通过吸附试验探讨了菌体对Cu、Cd的吸附能力,用化学试剂逐步提取法分析了Cu、Cd在黑曲霉菌体中的化学形态及其Cu、Cd含量,采用差速离心法分离黑曲霉菌体的亚细胞结构并测定其各组分Cu、Cd含量,并对Cu、Cd处理后的黑曲霉菌株TLSF2的细胞壁进行了红外光谱分析。结果表明,Cd浓度保持50 mg/L条件下,Cu浓度为200 mg/L时,菌株TLSF2对Cu的吸附量最大,达到17.76 mg/g;Cu浓度保持200 mg/L条件下,Cd浓度为50 mg/L时,菌株TLSF2对Cd的吸附量最大,达5.19 mg/g,表明该菌株对Cu、Cd有很强的耐受性和富集能力。并且证实细胞壁是菌株TLSF2富集Cu、Cd的主要部位,Cu、Cd的化学形态均以氯化钠提取态为主。菌株TLSF2吸附Cu的化学基团主要涉及羧基、氨基和羟基等,吸附Cd的化学基团主要包括酰胺基、氨基、羧基、羟基以及磷酸基等。

Discussion on the Absorption Mechanism of Aspergillus niger TLSF2 Strain to Copper and Cadmium in Water

Aspergillus niger TLSF2 is a new-found fungus with heavy metal tolerance. In the study, in order to understand the adsorption mechanism of the strain to copper and cadmium in the water deeply, a series of experiments have done. The strain's adsorption capacity was determined by AAS, the analysis of chemical form was done and content of the copper and cadmium in the A. niger TLSF2 was determined using the chemical reagent extraction step by step. Then the subcellular structure of the strain was separated by differential centrifugation, the copper and cadmium content of the component was de-termined,and the FTIR result of cell wall treated with copper and cadmium was discussed. The results showed that the largest copper adsorption of strain was up to 17.76 mg/g when the stress of cadmium and copper were 50 mg/L and 200 mg/L, the highest cadmium adsorption was 5.19 mg/g when the cadmium and copper were 50 mg/L and 200 mg/L respectively, which reflected the strain's high tolerance and strong adsorption ability to copper and cadmium. In addition, the cell wall were veri-fied the primary adsorbing position to heavy metal, the sodium chloride extraction condition were the main chemical form of the heavy metal's combination. The carboxyl, amino and hydroxyl groups were proved the major perssad to integrate the cop-per, besides, the cadmium binding site included the amide and phosphate group.