Bioremediation of Chromium by Microorganisms and Its Mechanisms Related to Functional Groups

Abstract

Heavy metals generated mainly through many anthropogenic processes, and some natural processes have been a great environmental challenge and continued to be the concern of many researchers and environmental scientists. This is mainly due to their highest toxicity even at a minimum concentration as they are nonbiodegradable and can persist in the aquatic and terrestrial environments for long periods. Chromium ions, especially hexavalent ions (Cr(VI)) generated through the different industrial process such as tanneries, metallurgical, petroleum, refractory, oil well drilling, electroplating, mining, textile, pulp and paper industries, are among toxic heavy metal ions, which pose toxic effects to human, plants, microorganisms, and aquatic lives. This review work is aimed at biosorption of hexavalent chromium (Cr(VI)) through microbial biomass, mainly bacteria, fungi, and microalgae, factors influencing the biosorption of chromium by microorganisms and the mechanism involved in the remediation process and the functional groups participated in the uptake of toxic Cr(VI) from contaminated environments by biosorbents. The biosorption process is relatively more advantageous over conventional remediation technique as it is rapid, economical, requires minimal preparatory steps, efficient, needs no toxic chemicals, and allows regeneration of biosorbent at the end of the process. Also, the presence of multiple functional groups in microbial cell surfaces and more active binding sites allow easy uptake and binding of a greater number of toxic heavy metal ions from polluted samples. This could be useful in creating new insights into the development and advancement of future technologies for future research on the bioremediation of toxic heavy metals at the industrial scale.

Microalgae-based wastewater treatment for developing economic and environmental sustainability: Current status and future prospects

“…Through ion exchange, the metal ions in the surrounding wastewater are exchanged with element ions held on the cell surface such as Ca, K and Na ( Jais et al, 2017 ). During the process of passive biosorption, metal ions in the cationic form are physically adsorbed over the microalgal cell surface that contains functional groups like amino (-NH 2 ), carboxyl (-COOH), hydroxyl (-OH), and sulfhydryl (-SH) ( Ayele and Godeto, 2021 ). Several factors affect the biosorption process, including biomass concentration, initial metal concentration, and operational factors such as pH, temperature, concentration of the biosorbent, and concentration of the initial metal ion ( Ayele and Godeto, 2021 ).…”

“…During the process of passive biosorption, metal ions in the cationic form are physically adsorbed over the microalgal cell surface that contains functional groups like amino (-NH 2 ), carboxyl (-COOH), hydroxyl (-OH), and sulfhydryl (-SH) ( Ayele and Godeto, 2021 ). Several factors affect the biosorption process, including biomass concentration, initial metal concentration, and operational factors such as pH, temperature, concentration of the biosorbent, and concentration of the initial metal ion ( Ayele and Godeto, 2021 ). However, the use of freely suspended microalgae as biosorbent has some limitations such as their small size, low mechanical strength, and the difficulty to separate the biomass and effluent ( Salam, 2019 ).…”

Peculiarities of adsorption of Cr (VI) ions on the surface of Chlorella vulgaris ZBS1 algae cells

“…Green algae, when used as adsorbents, have some additional advantages over other microorganisms due to their large surface area, large volume of mucus with high binding affinity and simple nutrient requirements [ 47 ].…”

Structural Properties of Graphene Oxide Prepared from Graphite by Three Different Methods and the Effect on Removal of Cr(VI) from Aqueous Solution

“…Industrial wastewater as one of the three industrial wastes (solid waste, wastewater and waste gas) and how to treat it efficiently and stably at a low price remains a challenge for scientific researchers. As a heavy metal element, chromium (Cr) is commonly found in large quantities as trivalent and hexavalent [Cr(VI)] compounds in the wastewater of many industries, such as electroplating, tannery, chemical, pigment, metallurgy and so on [ 3 , 4 ]. All chromium compounds are toxic, notably Cr(VI) is far more toxic than chromium metal, trivalent or tetravalent chromium [ 5 ].…”