Huang Ting-Lin, Zhou Shi-Lei, Zhang Hai-Han, Zhou Na, Guo Lin, Di Shi-Yu, Zhou Zi-Zhen
School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China.
Int J Mol Sci. 2015 Apr 10;16(4):8008-26. doi: 10.3390/ijms16048008.
Treatment of micro-polluted source water is receiving increasing attention because of environmental awareness on a global level. We isolated and identified aerobic denitrifying bacteria Zoogloea sp. N299, Acinetobacter sp. G107, and Acinetobacter sp. 81Y and used these to remediate samples of their native source water. We first domesticated the isolated strains in the source water, and the 48-h nitrate removal rates of strains N299, G107, and 81Y reached 33.69%, 28.28%, and 22.86%, respectively, with no nitrite accumulation. We then conducted a source-water remediation experiment and cultured the domesticated strains (each at a dry cell weight concentration of 0.4 ppm) together in a sample of source water at 20-26 °C and a dissolved oxygen concentration of 3-7 mg/L for 60 days. The nitrate concentration of the system decreased from 1.57 ± 0.02 to 0.42 ± 0.01 mg/L and that of a control system decreased from 1.63 ± 0.02 to 1.30 ± 0.01 mg/L, each with no nitrite accumulation. Total nitrogen of the bacterial system changed from 2.31 ± 0.12 to 1.09 ± 0.01 mg/L, while that of the control system changed from 2.51 ± 0.13 to 1.72 ± 0.06 mg/L. The densities of aerobic denitrification bacteria in the experimental and control systems ranged from 2.8 × 10(4) to 2 × 10(7) cfu/mL and from 7.75 × 10(3) to 5.5 × 10(5) cfu/mL, respectively. The permanganate index in the experimental and control systems decreased from 5.94 ± 0.12 to 3.10 ± 0.08 mg/L and from 6.02 ± 0.13 to 3.61 ± 0.11 mg/L, respectively, over the course of the experiment. Next, we supplemented samples of the experimental and control systems with additional bacteria or additional source water and cultivated the systems for another 35 days. The additional bacteria did little to improve the water quality. The additional source water provided supplemental carbon and brought the nitrate removal rate in the experimental system to 16.97%, while that in the control system reached only 3.01%, with no nitrite accumulation in either system. Our results show that aerobic denitrifying bacteria remain highly active after domestication and demonstrate the applicability of such organisms in the bioremediation of oligotrophic ecosystems.
由于全球层面的环境意识增强，微污染水源水的处理日益受到关注。我们分离并鉴定了好氧反硝化细菌动胶菌属N299、不动杆菌属G107和不动杆菌属81Y，并使用这些细菌对其原生水源水样本进行修复。我们首先在水源水中驯化分离出的菌株，菌株N299、G107和81Y的48小时硝酸盐去除率分别达到33.69%、28.28%和22.86%，且没有亚硝酸盐积累。然后我们进行了水源水修复实验，在20 - 26℃、溶解氧浓度为3 - 7mg/L的条件下，将驯化后的菌株（各自干重浓度为0.4ppm）一起培养在一份水源水样本中60天。系统的硝酸盐浓度从1.57±0.02降至0.42±0.01mg/L，而对照系统的硝酸盐浓度从1.63±0.02降至1.30±0.01mg/L，两者均无亚硝酸盐积累。细菌系统的总氮从2.31±0.12变为1.09±0.01mg/L，而对照系统的总氮从2.51±0.13变为1.72±0.06mg/L。实验系统和好氧反硝化细菌密度分别为2.8×10(4)至2×10(7)cfu/mL，对照系统为7.75×10(3)至5.5×10(5)cfu/mL。在实验过程中，实验系统和对照系统的高锰酸盐指数分别从5.94±0.12降至3.10±0.08mg/L和从6.02±0.13降至3.61±0.11mg/L。接下来，我们向实验系统和对照系统的样本中添加额外的细菌或额外的水源水，并将系统再培养35天。额外添加的细菌对改善水质作用不大。额外的水源水提供了补充碳源，使实验系统中的硝酸盐去除率达到16.97%，而对照系统中的硝酸盐去除率仅达到3.01%，两个系统均无亚硝酸盐积累。我们的结果表明，好氧反硝化细菌驯化后仍保持高活性，并证明了此类生物在贫营养生态系统生物修复中的适用性。
