基于生态风险评估探究溶藻细菌2-4的抑藻特性

Algicidal characteristics of Pseudomonas 2-4:based on ecological risk assessment

【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(Pseudomonas sp.),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(t_(1/2)=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(t_(1/2)=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.