3种细菌对小球藻生长和脱氮除磷效率的影响

Effects of Three Bacteria on the Growth and Nitrogen and Phosphorus Removal Efficiency of Chlorella pyrenoidosa

鉴于水资源日益紧缺且水污染问题日渐加剧的现状,藻菌共生系统作为一种节能环保的污水处理方式,有助于提高污水处理效率。通过人工模拟城市污水,选取3种污水处理中常用细菌地衣芽孢杆菌(Bacillus licheniformis)、枯草芽孢杆菌(Bacillus subtilis)和沼泽红假单胞菌(Rhodopseudomonas palustris)与小球藻构建藻菌共生系统,探究了不同细菌对蛋白核小球藻(Chlorella pyrenoidosa FACHB-5)生长以及污水脱氮除磷效率的影响。结果显示,在3种藻菌共生系统中,地衣芽孢杆菌为小球藻促生长菌,而枯草芽孢杆菌对小球藻生长有抑制作用,沼泽红假单胞菌对小球藻生长无显著影响(P>0.05),且沼泽红假单胞菌的生长受到小球藻的显著抑制(P<0.05)。在3个共生系统中,地衣芽孢杆菌-小球藻共生系统中小球藻生物量最高,第2天水体的总氮和总磷去除率分别达到79.84%和83.48%,显著高于小球藻单独培养试验组(P<0.05)。研究表明,3种藻菌共生系统中,细菌与微藻间的关系具有特异性,应选择适宜的促生菌与微藻共培养,合适的藻菌共生系统可提高水体总氮和总磷的去除率。

The interactions of algal-bacterial consortia can improve the efficiency of waste water treatment and are characterized by energy-saving and environmental friendliness.In this study,three commonly used bacteria(Bacillus licheniformis,Bacillus subtilis and Rhodopseudomonas palustris)were selected to co-culture with Chlorella pyrenoidosa(FACHB-5)to construct the algal-bacterial symbiotic system.The effects of the different bacteria on the growth of C.pyrenoidosa and the efficiency of nitrogen and phosphorus removal from waste water were investigated and compared.B.licheniformis,B.subtilis,R.palustris and C.pyrenoidosa(FACHB-5)in the exponential growth phase were mix-cultured in an artificially composed urban sewage,at initial concentrations of 1×10^(7) CFU/mL for the three bacteria and 2×10^(6) cells/mL for the algae.Each trial was run in triplicate with a control group,the trials lasted 7 days and the culture was sampled each 24 h.B.licheniformis promoted algal growth,B.subtilis inhibited algal growth,while R.palustris had no significant effect on algal growth(P>0.05).On the contrary,C.pyrenoidosa FACHB-5 significantly inhibited the growth of R.palustris(P<0.05).The maximum algal biomass appeared in the C.pyrenoidosa-B.licheniformis symbiotic system,and the removal rates of TN and TP in this system reached 79.84%and 83.48%,respectively,significantly higher than in the control(algae only)(P<0.05).Our study indicated that the interactions between bacteria and microalgae for the three algal-bacterial symbiotic systems were very different,so it is important to select suitable probiotics for the algal-bacterial consortium.The symbiotic interactions in a properly composed algal-bacterial consortia can remove TN and TP from water more efficiently than microalgae alone.