Department of Environmental Engineering, Yonsei University, Wonju, Republic of Korea.
PLoS One. 2019 Mar 12;14(3):e0213370. doi: 10.1371/journal.pone.0213370. eCollection 2019.
Algicidal bacteria have received broad acceptance as an ecofriendly tool for controlling harmful algal blooms. However, their practical application is still limited to the lab-scale tests due to the complex alga-bacterium interactions in different nutrient statuses. In this study, the Aeromonas sp. L23 that exhibit relatively wide-spectrum in algicidal activity was isolated from a eutrophic agricultural lake. The physiological response of cyanobacteria and green to the algicidal activity under varied nutritional status were studied in an alga-bacterial co-culture. The algicidal activities of L23 against Microcystis aeruginosa UTEX LB 2385, Microcystis aeruginosa NHSB, Anabaena variabilis AG10064, Scenedesmus quadricauda AG10003, and Chlorella vulgaris AG10034 were 88 ± 1.2%, 94 ± 2.6%, 93 ± 0.5%, 82 ± 1.1%, and 47 ± 0.9%, respectively. The L23 cells had low algicidal activity in cell pellet (3%-9%) compared with the cell-free supernatant (78%-93%), indicating that the activity is induced by extracellular substances. Adding glucose, NaNO3, NH4Cl, and KH2PO4 to the co-culture raised the algicidal activity of the L23 against green algae by 5%-50%. Conversely, a 10%-20% decrease in activity occurred against the target cyanobacteria except M. aeruginosa UTEX LB 2385. These results indicated that the interspecific algicidal activity changes according to the nutritional status, which means that the alga-bacterium interaction will be more complex in the field where the nutritional status changes from time to time.
杀藻细菌作为一种控制有害藻类水华的环保工具已经得到广泛认可。然而，由于不同营养状态下藻类-细菌相互作用的复杂性，它们的实际应用仍然局限于实验室规模的测试。在这项研究中，从富营养化的农业湖中分离到一种具有广谱杀藻活性的气单胞菌 L23。在藻类-细菌共培养物中，研究了蓝藻和绿藻在不同营养状态下对杀藻活性的生理响应。L23 对铜绿微囊藻 UTEX LB 2385、铜绿微囊藻 NHSB、鱼腥藻 AG10064、四尾栅藻 AG10003 和普通小球藻 AG10034 的杀藻活性分别为 88±1.2%、94±2.6%、93±0.5%、82±1.1%和 47±0.9%。与细胞无沉淀（78%-93%）相比，L23 细胞的细胞沉淀中的杀藻活性较低（3%-9%），表明该活性是由细胞外物质诱导的。在共培养物中添加葡萄糖、NaNO3、NH4Cl 和 KH2PO4 可使 L23 对绿藻的杀藻活性提高 5%-50%。相反，除铜绿微囊藻 UTEX LB 2385 外，目标蓝藻的活性降低了 10%-20%。这些结果表明，种间杀藻活性会根据营养状态而变化，这意味着在营养状态不断变化的野外，藻类-细菌的相互作用将更加复杂。
