(1. 南華大學(xué) 城市建設(shè)學(xué)院，衡陽 421001；
2. 南華大學(xué) 鈾礦冶生物技術(shù)國防重點學(xué)科實驗室，衡陽 421001)
摘 要: 在厭氧條件下，研究腐敗希瓦氏菌還原U(Ⅵ)的特性，考察腐殖質(zhì)模式物蒽醌−2−磺酸鈉(AQS)濃度、金屬離子(Cu2+ 、Ca2+、Cr6+等)與有毒有機(jī)物等對U(Ⅵ)還原的影響。結(jié)果表明：腐敗希瓦氏菌可以利用一些有機(jī)酸鹽作為電子供體，以AQS作為電子穿梭載體，進(jìn)行醌呼吸，高效還原U(Ⅵ)。當(dāng)AQS的濃度為0~2 mmol/L時，能顯著加速U(Ⅵ)的還原過程；當(dāng)AQS的濃度高于2 mmol/L時，隨著AQS濃度從2 mol/L增加到10 mol/L，AQS與U(Ⅵ)競爭電子，明顯抑制U(Ⅵ)的還原。同時，Ca2+和Cu2+對U(Ⅵ)的還原均表現(xiàn)出較強(qiáng)的抑制作用，Cu2+的抑制作用通過抑制呼吸鏈上脫氫酶的活性實現(xiàn)；但Mn2+和Cr6+ 對腐殖質(zhì)還原U(Ⅵ)的影響較小，在60 h內(nèi)，未觀測到溶液中Cr6+濃度的明顯變化。金屬離子對還原U(Ⅵ)抑制作用的強(qiáng)度與其濃度正相關(guān)。環(huán)境中甲苯、三氯乙酸和對硝基苯酚等有毒有機(jī)物可以作為電子供體被腐敗希瓦氏菌利用而降解，得到氧化降解，同時實現(xiàn)U(Ⅵ)的高效還原。
關(guān)鍵字: U(Ⅵ)；蒽醌−2−磺酸鈉(AQS)；腐敗希瓦氏菌；重金屬；有毒有機(jī)物
（1. School of Urban Construction, University of South China, Hengyang 421001, China;
2. Key Discipline Laboratory for National Defence for Biotechnology in Uranium Mining and Hydrometallurgy,
University of South China, Hengyang 421001, China）
Abstract:In the presence of anthraquinone-2-sulfonate(AQS), the reduction of U(Ⅵ) by Shewanella putrefaciens (S.putrefaciens) was investigated under anaerobic environment. The influences of different concentrations of AQS, heavy metal ions (e.g., Cu2+, Ca2+, Cr6+) and toxic organic compounds on the reduction of U(Ⅵ) were studied. The experimental results show S.putrefaciens is capable of utilizing various organic acids as electron donors and AQS as a electron shuttle vector to reduce U(Ⅵ) efficiently under anaerobic condition. At low concentration of 0−2 mol/L AQS is an effective accelerator for bioreduction of U(Ⅵ). However, when the concentration of AQS is more than 2 mmol/L, the effect of acceleration is gradually decreased with increasing concentration of AQS (2−10 mmol/L). AQS not only acts as an electron shuttle vector during the reduction process, but also as the competitor for electron from respiration chain. Meanwhile, Cu2+ has a strongly negative effect on the bioreduction of U(Ⅵ), as a typical inhibitor of dehydrogenases in respiration chain. A strong inhibition of bioreduction of U(Ⅵ) by Ca2+ is also observed. But, the reduction of U(Ⅵ) is only weakly affected by Cr6 + and Mn2+, and in 60 h the significant change of the concentration of Cr6+ in the solution is not observed. The effect of metal ions on U(Ⅵ) reduction has a positive correlation with their concentrations. Some toxic organic compounds, such as toluenes, trichloroacetic acid and p-nitrophenol, are capable of being utilized as electron donors to reduce U(Ⅵ) efficiently by S.putrefaciens and be degraded at the same time.
Key words: U(VI); anthraquinone-2-sulfonate(AQS); Shewanella putrefaciens; heavy metal; toxic organic compounds
