HN-02菌脱氮性能与抗氧化酶体系对盐胁迫响应特征研究

发布时间：2018-01-07 01:20

  本文关键词：HN-02菌脱氮性能与抗氧化酶体系对盐胁迫响应特征研究　出处：《成都理工大学》2015年硕士论文　论文类型：学位论文

  更多相关文章： 盐胁迫 生物脱氮 异养硝化-好氧反硝化 抗氧化酶系统

【摘要】：目前,氮素是造成我国水体污染的主要原因之一,脱氮技术,特别是废水生物脱氮技术因其具有经济、高效、无害的特点,引起世界各国的普遍关注。脱氮微生物是废水生物脱氮技术的核心,但其脱氮效率容易受水质条件如盐度等胁迫因素影响。本研究基于实验室从淡水环境筛选的异养硝化-好氧反硝化菌HN-02(Aeromonas hydrophila sp.)展开,研究其在不同盐度冲击下(Na Cl浓度0~20g/L)的脱氮性能和抗氧化酶体系的响应变化特征,探究盐分胁迫下HN-02菌株的响应机制;此外,通过对HN-02菌株进行不同盐度驯化,比较研究了驯化后HN-02菌株脱氮特性和抗氧化酶响应特征。研究结果表明:(1)HN-02是一株耐盐菌,可在0~20g/L的盐度冲击下生长、繁殖。菌株生长状况和脱氮速率与盐浓度呈反相关,6h内,盐度0 g/L、5 g/L、10g/L、15g/L和20g/L氨氮降解速率分别为3.66 mg/L·h、2.95 mg/L·h、2.82 mg/L·h.1.92 mg/L·h和1.08 mg/L·h。(2)HN-02在遭遇盐胁迫时,机体内抗氧化酶的应急反应是系统性的,抗氧化酶体系如SOD(superoxide dismutase,超氧化物歧化酶)和POD(peroxidase,过氧化物酶)是协同作用的。就抗氧化酶体系抵抗盐度胁迫敏感性而言:SODPOD,但就酶活力变化幅度来看CATSODPOD,CAT(catalase,过氧化物酶)活力调节幅度分别较SOD、POD高32.06 U/g和117.24 U/g。(3)驯化后HN-02生长状况和脱氮速率仍与盐度浓度成反相关,6h内盐度5 g/L、10 g/L、15g/L和20 g/L的OD600和生长速率分别为0.647(0.097 h-1)、0.590(0.087 h-1),0.522(0.076 h-1)和0.233(0.028 h-1);生长速率分别较驯化前提高0.058 h-1(148.93%)、0.054 h-1(160.20%)、0.056 h-1(276.03%)和0.025h-1(773.68%);其脱氮速率分别为5.17mg/L·h,5.21 mg/L·h,3.87 mg/L·h和2.14mg/L·h,分别较驯化前提高2.22 mg/L·h(75.14%),2.39 mg/L·h(85.04%),1.95 mg/L·h(101.25%)和1.06 mg/L·h(98.10%)。(4)SOD在HN-02耐盐性方面起到了关键作用,盐度驯化后HN-02能够迅速的诱导启动SOD抗氧化酶体系来进行防御。SOD在整个胁迫时期都将发挥作用,并且在胁迫初段表现的更为敏感。(5)驯化后,盐胁迫下POD的活力受抑制的程度大于SOD,POD的诱导产生能力可能小于SOD。同时,推断抗氧化酶系统发挥作用的顺序是:SODPODCAT,但是当POD不足以清除H2O2危害时,CAT和POD会同时协同作用调节机体不利影响,解除或缓解胁迫。(6)15 g/L可能是HN-02解除或者缓解盐度胁迫的临界点,盐度15g/L以内SOD的活力随着盐度升高而提高,最大平均增加速率(盐度15g/L)为30.05U/g·h。当盐度高于15 g/L,POD和CAT活性受到抑制。(7)HN-02-05、HN-02-10、HN-02-15和HN-02-20在遭受20 g/L盐度冲击时,氨氮降解能力和生长状况不一致。其平均生长速率分别为0.027 h-1,0.033 h-1,0.058 h-1和0.013 h-1,其中HN-02-15生长速率最快。就脱氮能力而言,驯化盐度越接近冲击盐度(20g/L)脱氮效果越好,其氨氮降解速率分别为1.71 mg/L·h、1.91 mg/L·h、5.92 mg/L·h和6.99 mg/L·h,其中HN-02-20效果最好。现阶段,异养硝化—好氧反硝化菌应用于高盐废水脱氮还处于研究初期,其耐盐机理的研究十分缺乏。加强微生物在盐度胁迫下脱氮特性和抗氧化酶体系响应特征研究,有助于完善盐胁迫下废水生物脱氮的机理,为应对策略与技术研发提供参考。
[Abstract]:At present, nitrogen is one of the main causes of water pollution in China, nitrogen removal technology, especially wastewater biological nitrogen removal technology because of its economic, efficient, harmless, caused widespread concern of the world. Microbial nitrogen removal is the core technology for nitrogen removal wastewater, but the removal efficiency of nitrogen is easily affected by water conditions as salinity stress factors. This research is based on the screening of heterotrophic nitrification from freshwater environment laboratory aerobic denitrifying bacteria HN-02 (Aeromonas hydrophila sp.), on the impact of different salinity (Na Cl concentration 0~20g/L) nitrogen removal performance and antioxidant system response characteristics, response mechanisms under salt stress strain HN-02; in addition, the effects of salinity on HN-02 was domesticated of domesticated strain HN-02 nitrogen removal characteristics and antioxidant response characteristics. The results show that: (1) HN-02 is a strain of resistance Salt bacteria can grow, in 0~20g/L under salinity shock propagation. The growth of strains and the denitrification rate was negatively correlated with salt concentration, 6h, salinity of 0 g/L, 5 g/L, 10g/L, 15g/L and 20g/L ammonia degradation rate were 3.66 mg/L, 2.95 h, mg/L, h, mg/L, h.1.92, mg/L 2.82 h and 1.08 mg/L h. (2) HN-02 in the event of emergency response to salt stress, antioxidant enzymes in the body is systemic, antioxidant enzyme system such as SOD (superoxide dismutase, superoxide dismutase (peroxidase) and POD, peroxidase). It is the synergistic effect of antioxidant enzyme system resistance to salinity stress sensitivity: SODPOD, but the amplitude change of enzyme activity of CATSODPOD, CAT (catalase, peroxidase) activity amplitude compared with SOD POD, 32.06 U/g and 117.24 U/g. (3 HN-02) after acclimation growth and nitrogen removal rate is inversely correlated with salinity concentration, salinity in 6h 5 g/L, 10 g/L 15g/L. 鍜，

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