title: Continuous-release beads of natural allelochemicals for the long-term control of cyanobacterial growth: Preparation, release dynamics and inhibitory effects.
abstract: The effects of allelochemicals on cyanobacterial blooms have been observed for more than 20 years; however, the use of these compounds, usually involving a "direct-added" mode, has clear disadvantages, such as a short activity period or temporarily excessive localized concentration. Here, a simulated-allelopathy mode to facilitate the application of allelochemicals was proposed and tested on Microcystis aeruginosa. The continuous-release beads of 5,4'-dihydroxyflavone (DHF) were constitutive of a polymer matrix and showed a high drug-loading rate (47.18%) and encapsulation efficiency (67.65%) with a theoretical release time of approximately 120 d. Cyanobacterial growth tests showed that the DHF beads had long-term inhibition effects (>30 d), whereas those of "direct-added" DHF to cells lasted a maximum of 10 d. The beads also continuously affected the superoxide dismutase, catalase, and lipid peroxidation of M. aeruginosa. The inhibitory effects of DHF beads on cyanobacterial growth increased as initial cell densities of M. aeruginosa decreased, suggesting that the beads inhibit cyanobacterial activity more effectively in the early bloom phase. Consequently, the anti-cyanobacterial beads represent a novel application mode of allelochemicals with long-term inhibitory effects on cyanobacterial growth. Our study demonstrates that the successful application of allelochemicals offers great potential to control harmful cyanobacterial blooms, especially at the initial stage of development.
authors.affiliation: College of Environmental & Resource Sciences (CERS), Zhejiang University, 310012 Hangzhou, PR China.
authors.forename: Haomin
authors.initials: H
authors.lastname: Huang
authors.affiliation: College of Environmental & Resource Sciences (CERS), Zhejiang University, 310012 Hangzhou, PR China; Ocean College, Zhejiang University, 310012 Hangzhou, PR China. Electronic address: prana@zju.edu.cn.
authors.forename: Xi
authors.initials: X
authors.lastname: Xiao
authors.affiliation: Ocean College, Zhejiang University, 310012 Hangzhou, PR China.
authors.forename: Fang
authors.initials: F
authors.lastname: Lin
authors.affiliation: Department of Experimental Limnology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, 2 Alte Fischerhütte, Neuglobsow, Germany.
authors.forename: Hans-Peter
authors.initials: HP
authors.lastname: Grossart
authors.affiliation: College of Environmental & Resource Sciences (CERS), Zhejiang University, 310012 Hangzhou, PR China.
authors.forename: Zeyu
authors.initials: Z
authors.lastname: Nie
authors.affiliation: College of Environmental & Resource Sciences (CERS), Zhejiang University, 310012 Hangzhou, PR China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Sun
authors.affiliation: College of Environmental & Resource Sciences (CERS), Zhejiang University, 310012 Hangzhou, PR China.
authors.forename: Chen
authors.initials: C
authors.lastname: Xu
authors.affiliation: College of Environmental & Resource Sciences (CERS), Zhejiang University, 310012 Hangzhou, PR China. Electronic address: shijiyan@zju.edu.cn.
authors.forename: Jiyan
authors.initials: J
authors.lastname: Shi
mesh_terms: D000458:Cyanobacteria / Q000187:drug effects*; D046931:Microcystis / Q000187:drug effects; D010675:Pheromones
chemical_list: D010675:Pheromones
keywords: 5,4′-dihydroxyflavone; Allelochemical; Continuous-release bead; Cyanobacterial bloom control; Inhibition efficiency; Release kinetics