一株气单胞菌胞外物质对铜绿微囊藻生理生化特性的影响

发布时间：2018-05-22 15:13

  本文选题：气单胞菌 + 胞外物质　； 参考：《山东大学》2015年硕士论文

【摘要】：水体富营养化程度日益加剧,藻类水华频发,已经成为困扰我国乃至世界的较为严重的环境污染问题之一。目前对于藻类水华的治理方法包括物理措施、化学措施和生物措施等,其中以溶藻细菌为代表的微生物抑藻技术崭露头角,成为人们日益关注和研究的焦点。课题组前期从水库中分离获得一株溶藻细菌FM,经鉴定为气单胞菌(Aeromonas sp. strain FM)。本文在此基础上以水华暴发常见藻类铜绿微囊藻(Microcystis aeruginosa)为研究对象,初步探讨了气单胞菌菌株FM的胞外物质对铜绿微囊藻生理生化特性的影响,主要研究结果如下：1)菌藻密度和环境因素对气单胞菌菌株FM的溶藻效应的影响。当气单胞菌初始菌浓度达到3.4×108cfu·mL-1及以上时,具有明显的溶藻效果,可有效作用于藻密度达到2.45×107cells · mL-1的铜绿微囊藻；溶藻效应发生的最佳温度为25℃,菌藻共培养体系处于偏碱性环境,且在光照充分条件下溶藻效果更好。2)以LB液体培养基培养气单胞菌菌株FM、制备具有溶藻活性的胞外物质,优化培养方法与培养条件。经优化获得的最佳培养时间为24h,温度为30。C,pH为8。经液体培养和固体平板培养菌株FM制备得到的细菌胞外物质对铜绿微囊藻均具有良好的溶藻效果,8天的溶藻效率分别为86.0%和84.7%。3)气单胞菌FM对铜绿微囊藻的生理生化指标的影响。检测分析表明,气单胞菌FM通过分泌胞外物质作用于铜绿微囊藻细胞,藻细胞胞内总蛋白和部分酶的含量降低,藻细胞的生理代谢活性发生改变；同时藻细胞的抗氧化能力被激发,膜脂过氧化水平提高；另外,藻细胞通过分泌胞外多糖保护自身免受伤害,藻细胞生长受到抑制,最终导致藻细胞的裂解和死亡。4)对处理第7天的铜绿微囊藻多糖进行提纯和制备,并初步研究其化学性质,结果表明：实验组的藻多糖干重明显高于空白组；在菌株FM胞外物质的作用下,藻细胞多糖的分子量比对照组有升高的趋势；经检测藻细胞多糖中含总糖、糖醛酸和硫酸根等组分。5)气单胞菌胞外物质对铜绿微囊藻藻毒素的释放有一定的抑制作用。但投加的气单胞菌胞外物质浓度较高时,会导致藻细胞破裂,使得胞外藻毒素含量明显升高。随着气单胞菌胞外物质浓度的增加,铜绿微囊藻胞内藻毒素的含量降低,同样表明气单胞菌胞外物质对铜绿微囊藻的生理代谢过程具有显著影响。
[Abstract]:The degree of eutrophication in water is becoming more and more serious, and the frequent occurrence of algae Shui Hua has become one of the more serious environmental pollution problems in our country and even in the world. At present, the control methods of algae Shui Hua include physical, chemical and biological measures, among which the microorganism inhibition technology, represented by algae-lysing bacteria, has become the focus of more and more attention and research. A algae-lysing bacterium, FM, was isolated from the reservoir and identified as Aeromonas sp. strain FM. On this basis, the effects of extracellular substances of Aeromonas aeruginosa strain FM on the physiological and biochemical characteristics of microcystis aeruginosa were studied. The main results were as follows: (1) the effect of algal density and environmental factors on the algae-lysing effect of Aeromonas aeruginosa strain FM. When the initial concentration of Aeromonas aeruginosa reached 3.4 脳 108cfu mL-1 and above, it had obvious algolytic effect, and could effectively act on microcystis aeruginosa with algae density up to 2.45 脳 107cells mL-1, and the optimum temperature for algolytic effect was 25 鈩，

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