Biodegradation of Chloroquine by a Fungus from Amazonian Soil, CBMAI 2758.

Concern over the presence of pharmaceutical waste in the environment has prompted research into the management of emerging organic micropollutants (EOMs). In response, sustainable technologies have been applied as alternatives to reduce the effects of these contaminants. This study investigated the capacity of filamentous fungi isolated from iron mine soil in the Amazon region to biodegrade the drug chloroquine diphosphate. An initial screening assessed the growth of four fungal strains on solid media containing chloroquine diphosphate: CBMAI 2752, CBMAI 2753, CBMAI 2754, and sp. cf. CBMAI 2758. Among them, sp. cf. CBMAI 2758 was selected for further testing in liquid media. A Box-Behnken factorial design was applied with three variables, pH (5, 7, and 9), incubation time (5, 10, and 15 days), and chloroquine diphosphate concentration (50, 75, and 100 mg·L), totaling 15 experiments. The samples were analyzed by gas chromatography-mass spectrometry (GC-MS). The most effective conditions for chloroquine biodegradation were pH 7, 100 mg·L concentration, and 10 days of incubation. Four metabolites were identified: one resulting from -deethylation M1 (4-(7-chloroquinolin-4-yl)-1-ethylpentane-1,4-diamine), two from carbon-carbon bond cleavage M2 (7-chloro--ethylquinolin-4-amine) and M3 (1,1-diethylpentane-1,4-diamine), and one from aromatic deamination M4 (1-ethylbutane-1,4-diamine) by enzymatic reactions. The toxicity analysis showed that the products obtained from the biodegradation of chloroquine were less toxic than the commercial formulation of this compound. These findings highlight the biotechnological potential of Amazonian fungi for drug biodegradation and decontamination.