Screening of some filamentous fungi for cadmium tolerance in aquatic environments

Heavy metals, such as cadmium (Cd), ingress into the human body via the food chain through animal and plant agro-chemicals, inducing epigenetic modifications, DNA harm, genetic mutations, and carcinogenesis. This investigation aimed to scrutinize and identify fungi tolerant to Cd toxicity in aqueous solutions using the poisoned food technique. Thirty fungal strains cultured under three distinct concentrations of Cd (0, 100, and 300 mg/L), with subsequent quantitative evaluation of mycelial growth. Cluster analysis delineated two fungal groups comprising 19 and 11 strains. Group II demonstrated superior performance across most evaluated traits compared to Group I, with exceptions noted for biomass at 0 mg/L and stress tolerance index (STI) at 300 mg/L Cd. Consequently, Group II was deemed the superior cohort. Within Group II, Epicocum nigrum exhibited the highest biomass production (2.17 and 1.35 g/L, respectively) at both 0 and 100 mg/L Cd concentrations, alongside the highest STI (2.18 and 0.43, respectively) at Cd levels of 100 and 300 mg/L. Conversely, Clonostachys rogersoniana displayed the highest biomass production (0.46 g/L) at a Cd concentration of 300 mg/L, coupled with the lowest percentage of inhibition (PI) (-11.35 and -31.40%, respectively) at Cd toxicity levels of 100 and 300 mg/L. Hence, the 11 strains within Group II, particularly E. nigrum and C. rogersoniana, exhibit promise for further investigation concerning their efficacy in Cd removal from aqueous solutions.