Fundamental fungal strategies in restoration of natural environment

Abstract

Fungi play vital role in nutrient cycling by achieving process of decomposition of organic matter and breakdown of complex compounds in nature. This role of fungi coupled with their fundamental strategy of adaptation to various environmental factors may be used for designing systems to enable the elimination of biopolymers and man-made xenobiotics from the environment via biosorption. Soil contaminants like heavy metals, radionuclides, polyaromatic hydrocarbons-PAHs and chemicals used in agriculture that are toxic and carcinogenic agents could be diminished or removed by activity of fungal exoenzymes. In this review, special attention was paid to lignolityc enzyme system expressed by white-rot fungi recognized as successful agent in bioremediation of a large variety of chemicals that are, like lignin, relatively long lived in the environment. Furthermore, fungi are very important in natural cycling of metal ions due to their great accumulation potential for heavy metals (Pb, Hg, Cd) and radionuclides ( 137 Cs), implicating them as good bioindicators of the pollution in urban and industrial areas and in contaminated forest ecosystems. These processes in macrofungi are influenced by environmental factors like metal concentrations of soil and substrate, pH, organic matter and contamination by atmospheric deposition as well as fungal factors like fungal structure, biochemical composition, decomposition activity, development of mycelium and sporocarps or portion of fruiting body. Concentration of radionuclides in fungi is determined by the amount of radioactivity precipitation, concentration of stable- non radioactive or analogous element in soil, soil characteristics (mineral composition, pH) and its taxonomic and nutritional identity. Macrofungi maintain ecological balances used as bioindicators or as remediation agents of contaminated environment. Also, edibility and medicinal properties are of a great importance for humans while majority of edible and medicinal mushrooms can accumulate high amounts of heavy metals and other environmental pollutants. This chapter summarizes relevant biological features of fungi (position in tree of life, nutritional strategy, enzyme systems), especially lignicolous macrofungi (mostly white-rot), as a basic tool for resolving physiological, ecological and biotechnological potential of fungi in changing polluted environment thus restoring the natural environment. © 2012 Nova Science Publishers, Inc. All rights reserved.