铬还原菌的分离筛选及其在微生物燃料电池生物阴极中的应用

Isolation of chromium reducing bacteria for application in biological cathode of microbial fuel cell

摘要:

【目的】水溶性的Cr(VI)对环境及人类造成的危害是社会亟待解决的问题。从Cr(VI)还原菌株的分离筛选、还原特性的分析和在微生物燃料电池中的应用方面为六价铬污染水体的微生物修复提供科学依据和新的方法。【方法】从黄河兰州段排污口采集样本，用平板法分离筛选获得具有Cr(VI)还原能力的菌株，并将Cr(VI)还原能力最强的LZU-26菌株应用到微生物燃料电池中，检测其产电能力和Cr(VI)还原特性。【结果】共分离得到21株具有Cr(VI)还原能力的菌株，其中LZU-26菌株Cr(VI)还原能力最强，属于Cellulosimicrobium cellilans。0.4 mmol/L初始Cr(VI)在LZU-26的作用下24 h铬还原率可达到95.89%，在48 h后达99.97%。将LZU-26运用在微生物燃料电池生物阴极，所获得的最大电压和最大功率密度分别为68 mV和6.8 W/cm2。生物阴极Cr(VI)还原率(68.9%)也远高于化学阴极(14.7%)和对照组(2.7%)。【结论】利用Cr(VI)还原菌作为微生物燃料电池生物阴极处理含铬废水，将会是一种高效、节能和环境友好的方法。

Abstract:

[Objective] Water-soluble hexavalent chromium (Cr(VI)) environment and human hazards are the social problems to be solved urgently. Thus, the purpose of this study was to provide a scientific basis and a new method for Cr(VI) contaminated water bioremediation by the purification of Cr(VI) reduction strains and the application of the reduction properties in microbial fuel cells. [Methods] The samples were collected from the outfall of Lanzhou section of Yellow River. Then screened strains with Cr(VI) reduction ability by plate method and applied LZU-26 strain with the strongest Cr(VI) reducing ability to microbial fuel cells, measured the electricity generation capacity and Cr(VI) reduction characteristics. [Results] Strain LZU-26 can reduce 95.89% of Cr(VI) after 24 h and 99.97% after 48 h at initial Cr(VI) concentration of 0.4 mmol/L respectively. Furthermore, applying LZU-26 to microbial fuel cell biological cathode, we obtained the maximum voltage is 68 mV and the maximum power density is 6.8 W/cm2. And the Cr(VI) reduction rate of biological cathode (68.9%) was higher than that of chemical cathode (14.7%) and control group (2.7%). [Conclusion] Strain LZU-26 as a bio-cathode of MFCs will be an efficient, economical and environmentally friendly technology of chromium-containing wastewater treatment.