ABSTRACT
Various types of wastewater have been widely utilized in microalgae and cyanobacteria cultivation for environmental and economic reasons. However, the problems of low cell growth and biomass contamination due to direct use of wastewater remain unresolved. In the present study, nitrate and phosphate were separated from wastewater by adsorption and subsequently used for cyanobacterial biomass production. To this end, an amine-grafted magnetic absorbent was synthesized. The synthesized absorbent recovered ca. 78% nitrate and 93% phosphate from wastewater. Regenerated medium was prepared using recovered nutrients as nitrogen and phosphate sources, which were efficiently assimilated by cyanobacterial culture. Compared to synthetic medium, there was no difference in growth and nutrient removal using regenerated medium. The proposed indirect method of wastewater utilization would prevent contamination of the produced biomass by unfavorable substances, which will broaden its potential applications.
Subject(s)
Nitrates/isolation & purification , Phosphates/isolation & purification , Spirulina/metabolism , Waste Disposal, Fluid/methods , Wastewater/chemistry , Adsorption , Amines , Animals , Biomass , Cell Line , Macrophages/drug effects , Mice , Nitrates/metabolism , Nitrogen/metabolism , Phosphates/metabolism , Spirulina/drug effects , Spirulina/growth & development , Wastewater/toxicityABSTRACT
SARS-CoV 3CL(pro) plays an important role in viral replication. In this study, we performed a biological evaluation on nine phlorotannins isolated from the edible brown algae Ecklonia cava. The nine isolated phlorotannins (1-9), except phloroglucinol (1), possessed SARS-CoV 3CL(pro) inhibitory activities in a dose-dependently and competitive manner. Of these phlorotannins (1-9), two eckol groups with a diphenyl ether linked dieckol (8) showed the most potent SARS-CoV 3CL(pro) trans/cis-cleavage inhibitory effects (IC(50)s = 2.7 and 68.1 µM, respectively). This is the first report of a (8) phlorotannin chemotype significantly blocking the cleavage of SARS-CoV 3CL(pro) in a cell-based assay with no toxicity. Furthermore, dieckol (8) exhibited a high association rate in the SPR sensorgram and formed extremely strong hydrogen bonds to the catalytic dyad (Cys145 and His41) of the SARS-CoV 3CL(pro).
