铜耐性优势植物根际土壤铜抗性菌株的筛选及其对铜的促溶作用

Isolation of Copper-resistant Bacteria from Rhizosphere Soils of Copper-tolerant Dominant Plants and Bacterial Solubilization of Copper

从铜矿废弃地重金属耐性优势植物根际土壤中分离筛选到两株抗高浓度Cu的细菌菌株HQN2和JYC17。对菌株HQN2和JYC17溶解难溶性Cu的作用进行了研究。结果表明:菌株HQN2和JYC17具有明显的溶解碳酸铜的能力,与接灭活菌对照相比,菌株HQN2和JYC17分别使培养液中水溶性Cu含量增加306%和136%,培养液的pH由初始的7.00分别降低到4.08和4.46,另外,Cu能促进供试菌株有机酸(葡萄糖酸、苹果酸和乙酸等)的合成。菌株HQN2和JYC17对土壤中难溶性Cu亦有明显的促溶作用。与接灭活菌对照相比,菌株JYC17和HQN2分别使土壤中交换态Cu含量增加110%和270%。经生理生化特征分析及16SrDNA序列分析,菌株HQN2和JYC17分别被鉴定为节杆菌属(Arthrobactersp.)和微杆菌属(Microbacteriumsp.)。

In this study two copper-resistant bacterial strains, HQN2 and JYC17, were isolated from rhizospheric soils of heavy metal-tolerant dominant plants growing in copper mining wasteland. Copper solubilization of strains HQN2 and JYC17 were investigated in solution culture and copper-contaminated soil. Compared to the control treatment （CK）, water-soluble Cu concentrations released from Cu2（OH）2CO3 by strains HQN2 and JYC17 increased by 306% and 136%, respectively, pH values in the bacterial inoculation treatments decreased from 7.00 to 4.08 （strain HQN2） and 4.46 （strain JYCI 7） respectively. Copper could promote the production of organic acids （such as gluconic, malic and acetic acids） by the tested strains. The two strains could significantly increase the exchangeable Cu compared to CK. The exchangeable Cu concentrations increased by 110% and 270% respectively compared to CK. Based on the physiological and biochemical tests as well as 16S rDNA gene sequence analysis, the bacterial strains HQN2 and JYC17 were identified as Arthrobacter sp. and Microbacterium sp. respectively.