Abstract
Heavy metal contaminated soils may pose risk and hazards to humans and the ecosystem. Therefore, in order to maintain good quality of soil and keep them free from contamination, continuous efforts have been made to develop technologies that are easy to use, sustainable and economically feasible. Physiochemical approaches have been widely used for remedying polluted soil. However they experience more difficulties for a large scale of remediation because of high costs and side effects. Phytoremediation has been proposed as a low cost, environmental friendly and effective method to remove toxicants from contaminated soils. However phytoremediation of heavy metal still has to deal with some important shortcomings such as phytotoxicity, slower than mechanical method and a limited mechanical uptake. Neverthless plant-associated endophytes can overcome these constraints, which can assist plants to accumulate higher amount of metals without increasing phytotoxicity. Many endophytic fungi have been found to be resistant to heavy metals and / or capable of degrading organic contaminates and endophyte- assisted phytoremediation has been documented as a promising technology for insitu remediation of contaminated soils. Fungi posses the biochemical and ecological capacity to decrease the risk associated with metals, metalloids and radionuclide’s either by chemical modification or by influencing chemical bioavailability. Furthermore the ability of fungi from extended mycelial networks makes them well suitable for bioremediation processes. The application of filamentous fungi can be a promising method or a valuable complement in situation of bacterial malfunction, in which bacterial cells fail to form the mycelia network to react with contaminants. This paper reviews the heavy metal resistant endophytic fungi and their role in phytoremediation and discuss some issues that have been raised surrounding this area of research
