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The white-rot fungi Phanerochaete chrysosporium have been widely applied in heavy metal bioremediation, which commonly results in a stress exposure. Exposure studies showed that Cd bioaccumulation triggered H 2 O 2 generation. Thereafter, the H 2 O 2 , as signal molecules, activated the enzymatic antioxidant response in the case of the conjunction of SOD and CAT. High levels of R (SOD/CAT) were found initially under Cd exposure, and then a significant decline occurred in time-course Cd exposure. Antioxidant activities also provided an alternative as an indication of the existence of antioxidant response upon Cd exposure, via coupling H 2 O 2 level with the variation in antioxidant activities. This finding potentially has implications for the understanding of tolerance behavior and detoxification mechanisms, which is beneficial to expand the application of P. chrysosporium in bioremediation biotechnology. [ABSTRACT FROM AUTHOR]

This study examines the role of oxalic acid in the uptake of Cd and participation in detoxification process in Phanerochaete chrysosporium. Cd-induced oxalic acid secretion was observed with growth inhibition and enzyme inactivation (LiP and MnP) of P. chrysosporium. The peak value of oxalic acid concentration was 16.6 mM at initial Cd concentration of 100 mg L. During the short-term uptake experiments, the uptake of Cd was enhanced and accelerated in the presence of oxalic acid and resulted in alleviated growth and enzyme inhibition ratios. The formation of a metal-oxalate complex therefore may provide a detoxification mechanism via effect on metal bioavailability, whereby many fungi can survive and grow in environments containing high concentrations of toxic metals. The present findings will advance the understanding of fungal resistance to metal stress, which could show promise for a more useful application of microbial technology in the treatment of metal-polluted waste. [ABSTRACT FROM AUTHOR]

Highlights: [•] Low concentration of Pb2+ could enhance the production of OH. [•] OH production declined when the initial Pb2+ concentration reached 400mgkg−1. [•] A remarkable correlation was found between OH content and oxalate concentration. [•] No obvious relationship was found between OH content and lignin degradation rate. [ABSTRACT FROM AUTHOR]