Taxonomy characterization and plumbum bioremediation of novel fungi

Abstract

The objective of this study was to investigate the screening, taxonomy characterization, Pb biosorption, and application of the high Pb-resistant fungus F1 separated from the heavy metal contaminated soil. Fungus F1 was screened through metal concentration gradient ranging from 25 to 4000 mg L^-1 . The internal transcribed spacers (ITS) of the strain was analyzed by molecular biotechnology. The adsorption conditions were also evaluated. The precipitation of fungus F1 was analyzed by Scanning Electron Microscopy (SEM), Fourier transformer infrared spectroscopy (FTIR) and energy dispersive X-ray (EDX) techniques. The Pb speciation was determined by BCR three-step sequential extraction. The highest concentration of fungus F1 resistance to Pb²⁺ was 3500 mg L^-1 . The fungus was identified as Trichoderma asperellum. The optimum condition for the Pb²⁺ removal rate was discovered as follows: MTL: 3500 mg L^-1 ; pH: 7; Pb2+ concentration: 800 mg L^-1 ; temperature was 30 °C; initial biosorbent dosage: 6% (v/v). The surface chemical functional groups of fungus F1 were amino, hydroxyl, and carbonyl groups, which may be involved in the biosorption of Pb. Application test showed that the exchangeable, acid-and water soluble Pb were reduced, and the sulfide, organic combination state, and residual Pb were increased. With the preferable absorption capacity, fungus F1 was considered to have good prospects of bioremediation.

Keywords: Trichoderma asperellum; adsorption; bioremediation; screening; taxonomy characterization.