【摘要】 六价铬（Cr（Ⅵ））是极具危害的环境污染物,利用微生物治理Cr（Ⅵ）污染是目前生物修复的热点之一,其中耐Cr（Ⅵ）微生物的筛选是关键。针对传统筛选方法培养基与Cr（Ⅵ）易相互作用的问题,文章提出先利用磷酸-Cr（Ⅵ）缓冲液浸泡筛选耐Cr（Ⅵ）微生物,然后在无Cr（Ⅵ）培养基上筛选的新方法（PCB法）。通过3种纯菌株进行筛选效果验证,并在尾矿土和草地土中与常规高温灭菌筛选（HS法）和过滤灭菌筛选法（FS法）进行筛选效果比较。纯菌株筛选结果表明,用含200 mg/L K2Cr2O7磷酸缓冲液（pH 7.4）浸泡微生物细胞2 h能有效筛选耐Cr（Ⅵ）菌株。土壤筛选实验表明,运用PCB法在尾矿土中获取菌落数为7.5×10⁴CFU/g,与HS法相当,显著高于FS法;而在草地土中获取菌落数为1.8×10⁴CFU/g,与FS法相当,显著低于HS法。HS法Cr（Ⅵ）在含200 mg/L K₂Cr₂O₇的牛肉膏蛋白胨培养基中回收率仅为53.8%,这是HS法获取菌落数高的原因。FS法筛选过程中微生物与Cr（Ⅵ）接触时间长,超过了微生物细胞生长对Cr（Ⅵ）的耐受极限,可能是FS法获得菌落数少的原因。总体而言,PCB法有效避免了上述缺陷,具有快速,准确,菌落生长好的特点。更多还原

【Abstract】 Hexavalent chromium（Cr（Ⅵ）） is considered as a harmful contaminant in environment, its microbial remediation is one of the research hot spots, and microbial screening method is the key point. Considering the interaction between Cr（Ⅵ）and medium, a novel microbial screening method（PCB method） is proposed. Vegetative cells are firstly soaked in phosphateCr（Ⅵ） buffer, then Cr（Ⅵ） resistant cells are cultured in Cr（Ⅵ） free medium. The effects of PCB method were assessed by three strains. The results indicated that PCB method is an effective way to screen the Cr（Ⅵ） resistant microbial cells. PCB method was also evaluated by screening Cr（Ⅵ） resistant microbes from the tailings and grass land soils, and this method was compared with two traditional methods, including heat temperature sterilization screening method（HS） and filter sterilization screening method（FS）. The resistant microbial number was 7.5×10⁴ CFU/g of the tailing soil when using PCB method, as much as using HS method but significantly higher than FS method. However, the resistant microbial number was 1.8×10⁴ CFU/g of the grass land soil when using PCB method, as much as FS method but significantly lower than HS method. In HS method, Cr（Ⅵ） recovery rate was 53.8% in nutrient broth with 200 mg/L K₂Cr₂O₇, which was the reason that the resistant microbial number increased. Prolonged exposure to high Cr（Ⅵ） levels results in growth tolerance limits of the microbes being exceeded, which was the reason that the resistant microbial number in FS method was low. In general, PCB method could screen Cr（Ⅵ） resistant microbes in a fast and accurate way with good quality of colony.更多还原