Adsorption Strategy for Removal of Harmful Cyanobacterial Species Microcystis aeruginosa Using Chitosan Fiber

Abstract

Microcystis aeruginosa is one of the predominant species responsible for cyanobacterial-harmful algal blooms (Cyano-HABs) in water bodies. Cyano-HABs pose a growing number of serious threats to the environment and public health. Therefore, the demand for developing safe and eco-friendly solutions to control Cyano-HABs is increasing. In the present study, the adsorptive strategy using chitosan was applied to remove M. aeruginosa cells from aqueous phases. Using a simple immobilization process, chitosan could be fabricated as a fiber sorbent (chitosan fiber, CF). By application of CF, almost 89% of cyanobacterial cells were eliminated, as compared to those in the control group. Field emission scanning electron microscopy proved that the M. aeruginosa cells were mainly attached to the surface of the sorbent, which was correlated well with the measurement of the surface area of the fiber. We tested the hypothesis that massive applications of the fabricated CF to control Cyano-HABs might cause environmental damage. However, the manufactured CF displayed negligible toxicity. Moreover, we observed that the release of cyanotoxins and microcystins (MCs), during the removal process using CF, could be efficiently prevented by a firm attachment of the M. aeruginosa cells without cell lysis. Our results suggest the possibility of controlling Cyano-HABs using a fabricated CF as a non-toxic and eco-friendly agent for scaled-up applications.

Current and Previous Green Technologies, Their Efficiency, Associated Problems, and Success Rates to Mitigate M. aeruginosa in Aquatic Environments

“…Their findings demonstrated that Q2 might be beneficial to the aquatic environment and offered a novel approach to the management of harmful cyanobacterial blooms (HCBs) in the future. Additionally, chitosan's anionic characteristics have been shown to make it an effective flocculant for removing cyano-HABs from water resources [63]. Ferric or aluminum salts are also extensively studied for controlling cyanobaterial blooms [64].…”

“…Chitosan is a non-toxic and biodegradable material, but the acidic condition of a chitosan solution sprayed over a water body for the control of M. aeruginosa can negatively influence water quality. Tiny chitosan particles (i.e., chitosan nanoparticles) can also cause physiological stress in aquatic biota [63].…”

Removal of Microcystis aeruginosa cells using the dead cells of a marine filamentous bacterium, Aureispira sp. CCB-QB1

“…Besides plants and microbes, another type of polysaccharide, chitosan, produced from shells of crustaceans has also attracted much attention as a bioflocculant to remove M. aeruginosa . The study conducted by Park et al (2020) demonstrated that chitosan fiber removed almost 89% of M. aeruginosa cells. Ma et al (2016) also reported that chitosan-aluminum chloride combined coagulants exhibited high removal efficiency (>90%) on M. aeruginosa cells.…”

Prokaryotic Diversity and Dynamics during Dinoflagellate Bloom Decays in Coastal Tunisian Waters

“…HAB dynamics include three critical phases (i.e., the triggering process, maintenance, and decline) and are generally influenced by several synergic abiotic factors, such as hydrodynamic processes, environmental conditions (e.g., temperature, salinity, and vertical mixing turbidity due to wind) [10,11], and nutrient availability [12]. In addition, some biotic factors, such as the compositions of microbial communities, in particular that of bacteria, have been increasingly mentioned as parameters influencing HAB dynamics because of their key roles in biogeochemical cycles and their production of algae-stimulating or -inhibiting elements [13,14]. Bacteria can stimulate HAB growth via nutrient regeneration or vitamin production [15,16] and can induce bloom decay via algicidal activities [17,18].…”