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研究报告

朱玲玲,曹佳妮,张文,葛世玫,董新姣,周茂洪,周江敏,李楠.一株耐铬细菌的鉴定及其还原铬性能分析[J].环境科学学报,2013,33(10):2717-2723

Identification of a chromium-tolerant bacterial strain and analysis of its Cr(Ⅵ)-reducing ability

摘要：从浙江温州工业区六价铬废水污染的土壤中采样分离得到一株耐铬细菌Y73.16S rRNA基因序列分析表明,该菌株为Staphylococcus(葡萄球菌)属菌,最高可在加有1600 mg·L^-1六价铬(K₂Cr₂O₇)的 LB培养基中生长.该菌为好氧生长,但在3种不同的氧压力下,包括有氧、无氧和兼性无氧(先有氧生长)的条件下都可以还原六价铬,而在兼性无氧(先有氧生长)的条件下达到最高还原效率,可在96 h内将1000 mg·L^-1的六价铬还原83%.另外,该菌株能在较宽的pH值(5~11)和温度(10~50℃)范围内还原六价铬,而最佳反应条件是pH=7 和30℃.随着接种量的增加,六价铬的还原率增加,但接种量超过10%时再增加接种量对六价铬还原的影响不明显.供试的大多数金属离子(50 mg·L^-1)对该菌株还原六价铬的影响也不明显.上述结果说明,菌株Y73有其独特的还原铬性能,以及在处理六价铬污染废水中的应用潜力.

Abstract：A chromium(VI)-tolerant bacterial strain, Y73, was isolated from the Cr(Ⅵ)-containing wastewater-contaminated soil near the industrial area of Wenzhou, Zhejiang Province. Y73 was identified as Staphylococcus on the basis of its 16S rRNA sequence analysis. The strain could tolerate 1600 mg·L^-1 Cr(Ⅵ) added as K₂Cr₂O₇ in LB medium. It was an aerobic strain but could reduce Cr(Ⅵ) to Cr(Ⅲ) under three conditions of oxygen stress: aerobic, anaerobic and aerobic growth followed by facultative anaerobic conditions. The highest Cr(Ⅵ) reduction rate was observed under aerobic growth followed by facultative anaerobic condition, with 83% of 1000 mg·L^-1 Cr(Ⅵ) reduced within 96 h. To our knowledge, there is few report about the reduction of Cr(Ⅵ) by bacterial strain under these three conditions. Moreover, the reduction of Cr(Ⅵ) occurred over a wide range of pH (5~11) and temperature (10~50℃) with the optimum performance at pH 7 and 30℃. The increased Cr(Ⅵ) reduction rate was observed with an increase of inoculums of the strain. However, the effects of the increasing inoculums on the Cr(Ⅵ) reduction became no obvious when the inoculums were over 10%. The effect of most of the tested metals (each with 50 mg·L^-1) on the Cr(Ⅵ) reduction was not significant. The results indicated that the strain possesses distinct capability for the Cr(Ⅵ) removal and the potential for application in the treatment of chromate(VI)-contaminated wastewaters.