[目的]基于生态安全评估,探索溶藻细菌及其分泌物的抑藻效果与机制。[方法]分离获得溶藻细菌2-4 (Pseudomonassp.),通过正交试验和动力学模型研究了菌株2-4及其分泌物的抑藻特性,并通过急性毒性试验对菌株2-4及其分泌物进行生态风险评估。[结果]菌株2-4在最优条件下接种体积比(V/V)为15%时对铜绿微囊藻的4 d抑制率达92.81%,抑藻反应符合一级动力学模型(t1/2=126 h)。菌株2-4具有抑藻多样性,首次报道了假单胞菌对斜生四链藻、蛋白核小球藻和丝藻的抑藻效果。菌株2-4分泌的抑藻活性物质分子量小于500 Da,不耐高温和强酸强碱。急性毒性试验结果显示,高于1.5%的菌液对大型溞有毒,高于2%的菌株分泌物对大型溞和稀有鮈鲫有毒,但对明亮发光杆菌无毒。较安全的使用范围内,菌株2-4 (V/V=1.5%)及其分泌物(V/V=10%)对藻华湖泊水样的叶绿素a去除率为4.83%–42.94%和30.62%–68.69%。[结论]本研究客观分析了假单胞菌2-4及其分泌物在生态安全使用范围内的实际抑藻效果,明晰了溶藻细菌生态毒性与抑藻效率的关系,为生物控藻实践提供理论参考。
[Objective]To explore the inhibitory effects of Pseudomonas 2-4 and its product on algae based on ecological risk assessment.[Methods]Algicidal bacterial strain 2-4(Pseudomonas sp.) was isolated,and the suppression of strain 2-4 and its product on algae was examined based on orthogonal test and kinetic stimulation.Acute toxicity test was conducted to evaluate the ecological risks.[Results] Under the optimal conditions,strain 2-4(V/V=15%) removed 92.81% of the Microcystis aeruginosa in 4 days,and the algal inhibition could be characterized by the first-order kinetic model (t1/2=126 h).Strain 2-4 had a broad-spectrum inhibitory activity and the inhibitory effects of Pseudomonas sp.on Ulothrix sp.,Chlorella pyrenoidosa,and Tetradesmus obliquus were reported for the first time.The product (<500 Da) from strain 2-4 had inhibitory effects on algae,but could be destroyed by high temperature and strong acid and alkali.The results of acute toxicity test showed the bacterial liquid at>1.5%(V/V) was toxic to Daphnia magna and the product at>2%(V/V) was toxic to D.magna and Gobiocypris rarus but nontoxic to Photobacterium phosphoreum.At the safe concentration,strain 2-4(V/V=1.5%) and its product (V/V=10%) decreased chlorophyll a in the lake with algae bloom by 4.83%–42.94% and 30.62%–68.69%,respectively.[Conclusion] We analyzed the algicidal effect of strain 2-4 and its product in the safe concentration and clarified the relationship between the ecological toxicity and the inhibitory effects of strain 2-4,hoping to provide a reference for biocontrol of algae.