重金属镉抗性菌株的筛选及其对镉活化作用的研究

Screening of cadmium-resistant strains and their effects on cadmium activation.

通过在培养基中加入一定浓度的Cd2+,从土壤中分离筛选出2株具有较强镉抗性及产酸能力的细菌JL-4和JC-9.经初步鉴定,JL-4和JC-9分别属于芽孢杆菌属(Bacillus sp.)和黄单胞菌属(Xanthomonas sp.).将菌株JL-4和JC-9接种到添加不溶性镉(100mg·L-1)的培养液中28℃培养48 h,接菌处理比不接菌对照培养液中有效镉含量分别增加1 392.3%和1 410.8%,培养液pH分别降低了2.87和3.18.将JL-4和JC-9分别接入含不同浓度重金属镉(100、200mg·kg-1)的土壤中28℃培养20 d,接菌处理比不接菌对照土壤中有效镉含量分别增加17.02%～100%(JL 4)和36.17%～61.80%(JC-9).菌株JL-4和JC-9的最适生长温度均为28℃,最适pH值分别为7和8.除对镉具有抗性外,两菌株对重金属铅、铜、镍、锌也具有一定抗性.

In this paper, cadmium-resistant bacteria were isolated from heavy metals-contaminated soils through agar plate containing Cd^2＋ as 3CdSO4·8H2O. The strains JL-4 and JC-9 were identified as Bacillus sp, and Xanthomonas sp., respectively, based on their morphological, physical, and biochemical characteristics, In the liquid medium containing Cd^2＋ （100 mg· L^-1） and inoculated with JL-4 or J C-9, the available Cd^2＋ content in supernatant was increased by 1 392.3% （JL-4） or 1 410.8% （JC-9）, compared with the control, and the pH was decreased to 2.87 （JL-4） or 3.18 （JC-9）, Soil cadmium （100,200 mg·kg^-1） activation experiments showed that the available Cd^2＋ content in soil inoculated with JL-4 or JC-9 was increased by 17.02 % - 100 % （JL-4） or 36.17 % - 61.80 % （JC-9）, compared with the control. The optimum temperature for JL-4 and JC- 9 was 28℃, and the optimum pH for them was 7 and 8, respectively. The two strains could also be resistant to Pb^2＋（800mg·L^-1）,Cu^2＋ （50mg·L^-1）,Ni^2＋（50mg·L^-1）,and Zn^2＋（200mg·L^-1）.