Loading Effects of Aminoclays in Co-Culture of Two Cyanobacterial _Microcytsis_ and _Anabaena_ Species as an Algicidal Role  
[PERSON]  
1 Department of BioNano Technology, Gachon University, 1342 Seongnamdaero, Sujeong-gu, Seongnam-si 13120, Korea; [EMAIL_ADDRESS] (M.K.N.); [EMAIL_ADDRESS] (V.K.H.B.); [EMAIL_ADDRESS] (O-S.K.)  
2 Department of Chemical Engineering--Environment, The University of Danang, University of Technology and Education, 48 Cao Thang St, Hai Chau Dist, Danang City 550000, Vietnam 2  
[PERSON]  
1 Department of BioNano Technology, Gachon University, 1342 Seongnamdaero, Sujeong-gu, Seongnam-si 13120, Korea; [EMAIL_ADDRESS] (M.K.N.); [EMAIL_ADDRESS] (V.K.H.B.); [EMAIL_ADDRESS] (O-S.K.)  
2 Department of Chemical Engineering--Environment, The University of Danang, University of Technology and Education, 48 Cao Thang St, Hai Chau Dist, Danang City 550000, Vietnam 2  
[PERSON]  
4 Green Chemistry and Environmental Biotechnology, University of Science and Technology, 217 Gajeong-ro, Daejeon 34141, Korea; cyahn@krrb.  
which were more than 1 billion dollars and 1 million dollars per year in Japan and Korea, respectively [1; 6; 7; 8; 9].  
Therefore, controlling and eradicating HABs through the use of algicides is of interest. Using chemicals such as CuSO\({}_{4}\) or biological approaches such as algicidal activity of prodigiosin [10] and lactic acid bacteria [11] have been utilized to consume these blooming species [12; 13; 14]. In addition, the mechanical treatment of HABs with clay is an alternative method offering noticeable advantages such as non-toxicity and local alternative sources [15]. It creates flocculation by clay-algae \"blocks\" formation and deposition on the floor of an aquatic environment [6]. South Korea's coastal farms also use clay to treat HABs. Although this is considered to be successful, large HABs have escaped from clay dispersion [1; 16; 17; 18; 19]. This method also requires a large amount of clay and incurs high costs, and moreover, cell breakdown, is only moderate, the result being that it is not possible to entirely prevent HABs release, all of which factors in limiting the applicability [17; 19; 20].  
In recent years, synthetic aminoclays (ACs), developed with unique properties to mimic natural clay, is a complex with nuclei consisting of metal cations (e.g., Ca\({}^{2+}\), Mg\({}^{2+}\), Al\({}^{3+}\), and Zn\({}^{2+}\)) sandwiched between two tetrahedral structures with connections to amino functional groups (with a precursor of 3-aminopropyltriethoxysilane, APTES) through covalent bonds (Figure S1) [21; 22]. The active sites (-NH\({}_{3}\)\({}^{+}\)) at the functional end sites create delaminated structures of clay sheets when dispersed in a water environment. Selected metal cation cores impact hydrodynamic size distribution in a one-pot sol-gel formation. AC was developed and applied to the formation of structures that encapsulate biological bodies, substances/materials such as enzymes, DNA, as well as other active organic substances [21; 22; 23; 24; 25]. A recent study identified and evaluated the antibacterial properties and low toxicity of AC to animal cells of magnesium aminoclay (MgAC) and calcium aminoclay (CaAC) [22]. Especially using MgAC, it has been investigated with selective algicidal activity of reddities in seawater [19] and both in increase of cell size and lipid contents in green microalgal culturing systems [26; 27].  
In the present study, the algicidal activity of AC was assessed on the basis of monocultures and co-cultures of two common toxic cyanobacterial blooms _Microystis_ and _Anabena_, as well as on cell-free media. The allelopathic interactions between the above microalgal strains and AC and with the cell-free medium also were observed. Therefrom, additional observations and assessments of the three AC types-utility for HAB control efficacies were derived.