Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou 730000, Gansu, PR China; Key Laboratory for Resources Utilization Technology of Unconventional Water of Gansu Province, Gansu Academy of Membrane Science and Technology, Lanzhou 730020, Gansu, PR China.
Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Tianshuinanlu #222, Lanzhou 730000, Gansu, PR China.
Bioresour Technol. 2020 Jul;307:123185. doi: 10.1016/j.biortech.2020.123185. Epub 2020 Mar 14.
The inhibition of denitrification by heavy metals is a problem in nitrogen wastewater treatment, but the solutions are rarely studied. In this study, Pseudomonas brassicacearum LZ-4, immobilized in sodium alginate-kaolin, was applied in an activated-sludge reactor to protect denitrifiers from hexavalent chromium (Cr(VI)). Q-PCR result showed that the strain LZ-4 was incorporated into activated sludge under the help of immobilization. In the non-bioaugmentation system, the removal efficiency of nitrate was decreased by 86.07% by 30 mg/L Cr(VI). Whereas, denitrification was protected and 95% of nitrate was removed continuously in immobilized-cell bioaugmentation system. Miseq sequencing data showed that bioaugmentation decreased the impact of Cr(VI) on microbial communities and increased the abundance of denitrifiers. Based on the results of biomass and extracellular polymers, activated sludge was protected from Cr(VI) toxicity. This discovery will provide a feasible technique for nitrogen wastewater treatment in the presence of distressing heavy metals.
重金属对反硝化的抑制是氮废水处理中的一个问题，但很少有研究解决该问题。在本研究中，将包埋在海藻酸钠-高岭土中的假单胞菌（Pseudomonas brassicacearum）LZ-4 应用于活性污泥反应器中，以保护反硝化菌免受六价铬（Cr(VI)）的影响。Q-PCR 结果表明，LZ-4 菌株在包埋的帮助下被纳入活性污泥中。在非生物强化系统中，30mg/L Cr(VI)使硝酸盐的去除效率降低了 86.07%。然而，在固定化细胞生物强化系统中，反硝化得到了保护，硝酸盐的去除率连续达到 95%。Miseq 测序数据显示，生物强化降低了 Cr(VI)对微生物群落的影响，增加了反硝化菌的丰度。基于生物量和胞外聚合物的结果，活性污泥受到 Cr(VI)毒性的保护。这一发现将为存在令人苦恼的重金属的氮废水处理提供一种可行的技术。
