Fungal species originating from chromium contaminated soil for ecofriendly and biotechnological processes

Abstract

Chromium contamination through different anthropogenic activities has been of great concern in soil health due to its toxicity and persistence. Microbial originating from contaminated industrial soil, including chromium tolerant fungi, is a promising approach to adapt green technologies. The current study investigated chromium contaminated industrial soils to explore the potential of indigenous fungi to tolerate, remove and detoxify high Cr(VI) contaminated matrices, as well as, the employed mechanisms by the most promising strain. This study involves fungal isolation from a chromium contaminated soil, selection and identification using ITS1 and tef1 sequences of the most chromium tolerant fungal strain. Mycoremediation was assessed by Cr(VI) removal and detoxification employing Lactuca sativa and Artemia salina tests, whereas scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and chromate reductase activity were evaluated to understand the implicated mechanisms. Isolation of 12 distinct fungal strains was carried out classified into three genera: Trichoderma sp., Penicillium sp., and Aspergillus sp. The identified strain as Trichoderma koningiopsis LBM 253 demonstrated the highest tolerance in solid medium and also removed up of the metal in liquid media at an high initial Cr(VI) concentration of 200 mg L−1. Fungus showed the ability to bioaccumulate Cr(VI) and SEM and EDX analysis showed that the adsorbed chromium was sequestered in the fungal mycelium as a precipitate. Moreover, high titers of chromate reductase activity were detected, and changes were observed in the extracellular and intracellular activity. Ecotoxicity tests carried out using plant (L. sativa) and animal (A. salina) biomarkers showed that T. koningiopsis decreases Cr(VI) toxicity in liquid systems. The findings of this study provide strong evidence that T. koningiopsis LBM 253 originated from chromium-contaminated soil is a promising fungus to be applied in mycoremediation and ecofriendly processes, offering the capability to tolerate, remove, and detoxify high concentrations of Cr(VI) from liquid media supplemented with the metal.