Importance of Free-Living Fungi in Heavy Metal Remediation

Abstract

Discharge of heavy metals from various human activities including agricultural practices and metal processing industries is known to cause adverse effects on the environment. Even though conventional technologies adopted for removal of heavy metals from polluted environment tend to be efficient, they are generally expensive and produce huge quantity of toxic chemical products. The use of biological materials including fungal biomass offers an economical, effective, and safe option for removing heavy metals and, therefore, has emerged as a potential alternative method to conventional treatment techniques. Among the various reme­diation strategies, biosorption of heavy metals by metabolically active or inactive nonliving (dead) biomass of fungal origin is an innovative and alternative technology for removal of metals from contaminated sites. Due to unique chemical composition, fungal biomass sequesters metal ions by forming metal complexes with certain reactive groups on their cell surface and does not require growth-supporting conditions. Biomass of numerous fungi like Aspergillus, Penicillium, Mucor, Rhizopus, etc., has been found to have highest metal adsorption capacities. Biomass generated as a by-product of fermentative processes offers great potential for adopting an economical metal-recovery system. The purpose of this chapter is to gather state of the art information on the use of fungal biomass and explores the possibility of exploiting them for heavy metal remediation.