Irpex lacteus, a white rot fungus applicable to water and soil bioremediation

Growth parameters, ligninolytic enzyme activities and ability to degrade po lycyclic aromatic hydrocarbons by the fungus Irpex lacteus were characteriz ed and compared with those of other white rot fungi capable of rapid decolo rization of poly R-478 and Remazol Brilliant Blue R dyes. I lacteus was abl e to grow on mineral and complex media and efficiently colonized sterile an d non-sterile soil by exploratory mycelium growing from a wheat straw inocu lum. In shallow stationary cultures growing on high nitrogen mineral medium containing 45 mM ammonium as nitrogen source, the fungus produced lignin p eroxidase (LTP), Mn-dependent peroxidase (MnP) and laccase simultaneously, the respective maximal activities of 70, 970 and 36 U/l being attained arou nd day 18. Growing in nitrogen-limited medium (2.4 mM ammonium), no LIP was formed and levels of MnP and laccase decreased significantly. During growt h in sterile soil, the fungus synthesized LIP and laccase but not MnP. I. l acteus efficiently removed three- and four-ringed PAHs from liquid media an d artificially spiked soil. The variety of ligninolytic enzymes, robust gro wth, capability of soil colonization and resistance to inhibitory action of soil bacteria make I. lacteus a suitable fungal organism for use in biorem ediation.