Bioremediation of metals by Pestalotiopsis sp.: isolation, characterization, and evaluation of operational parameters

Bioremediation employs microorganisms to remove metallic contaminants through physicochemical mechanisms. This study evaluated the biosorption of Cd²⁺, Cu²⁺, Pb²⁺, and Cr³⁺ ions by endophytic fungi of the genus Pestalotiopsis, isolated from tissues of Poaceae sp. grass. The effects of biomass concentration, contact time, and initial metal concentration on process efficiency were investigated. Increasing biomass reduced biosorption capacity, possibly due to biofilm formation that decreases the availability of active sites. Low initial concentrations favored removals above 98%, with emphasis on Cr³⁺ and Cu²⁺, which exhibited maximum biosorption capacities of 16.91 mg g⁻¹ and 11.71 mg g⁻¹, respectively. Adsorption followed the Langmuir model, indicating high affinity and monolayer adsorption, reaching equilibrium within 2 h and remaining stable up to 12 h. It was concluded that Pestalotiopsis sp. fungi are efficient and promising biosorbents for the removal of potentially toxic metals in effluents, representing a sustainable alternative for bioremediation.