Cyanobacteria mediated heavy metal removal: a review on mechanism, biosynthesis, and removal capability

ABSTRACT

Heavy metal in wastewater is a crucial concern due to its toxicological manifestations on human health, particularly in developing countries. Compared to different conventional heavy metal removal methods, cyanobacteria mediated heavy metal removal is a potential method, as it is a cost-effective, in situ operable, and green chemistry approach. They are excellent tools for multidirectional metal sequestration operations as they can simultaneously sequester metal through biosorption and bioaccumulation. Biosorption is a cell surface phenomenon, whereas bioaccumulation occurs inside the cell. This study reviewed deeply how cyanobacteria sequester heavy metal ions by these two processes from an ambient water body and the defense mechanism of cyanobacteria against metal-induced toxicity. Further, among the different components of the cyanobacteria's cell wall, this blue–green algae biosorb the metal ion mainly through Exopolysaccharide (EPS). The article discusses several pathways of EPS biosynthesis to know the potential engineering approach for producing this incredible polymer, which facilitates its metal ion adsorption property. Furthermore, we compare different cyanobacterial species’ ability to sequester heavy metals from water in different environmental conditions. Limnococcussp, Nostocmuscorum, and Synechococcus sp. PCC 7942 shows optimum efficiency based on heavy metal removal, multi-metal removal by biosorption and bioaccumulation, and contact time. Finally we for the first time, discussed the circadian clock application in the cyanobacterial metal ion sequestration process, which might disclose the molecular-level mechanisms of cyanobacteria to sequester metal ions and different defense mechanisms.

GRAPHICAL ABSTRACT

KEYWORDS:

• Bioremediation
• cyanobacteria
• bioaccumulation
• EPS
• circadian clock

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Abdullah Al-Amin

Abdullah Al-Amin A Doctoral Student in the Department of Chemistry and Environmental Science, New Jersey Institute of Technology, Under the supervision of Dr. Kim. He has completed his Bachelor and MS from Enviornmental Sciences.

Fahmida Parvin

Fahmida Parvin With an educational background of the PhD in earth system science and an MS in Environmental Sciences, she is a committed professional in environmental research and teaching. She explored field like organic geochemistry in her PhD and now would like to continue her research in identifying the occurrence and fate of emerging pollutant in different environmental matrix whose basic is also organic geochemistry. In addition, she has worked on water treatment using different nanomaterials and biosorbent.

Joydeep Chakraborty

Joydeep Chakraborty Dr. Joydeep is working as a post doctoral fellow in Texas A&M AgriLife Research lab. He worked on biochemical analysis and cell biology.

Yong-Ick Kim

Yong-Ick Kim Dr. Kim studies the biochemical mechanisms underlying circadian rhythms, the bodily and behavioral changes tied to the 24-hour daily cycle that are responsive to light and darkness. His research to date has focused on pinpointing the activation and inhibition of proteins integral to regulating the circadian clock and on the biochemical mechanisms that reset it. His interesting teaching area is Biochemistry and Molecular biology.