Abstract
Azo dyes are recalcitrant owing to their xenobiotic nature and exhibit high resistance to degradation processes. In the present study, different
Aspergillus
species (
A. flavus
,
A. fumigatus
,
A. niger
, and
A. terreus
) isolated from soil samples contaminated with industrial effluent, collected from Jeddah, Saudi Arabia, were analyzed for azo dye, Reactive Red 120 (RR120) biodegradation. The physicochemical parameters such as carbon (sucrose) and nitrogen (ammonium sulfate) sources, pH, and temperature affecting the biodegradation of RR120 were optimized using central composite design–response surface methodology (CCD-RSM). The maximum RR120 degradation was found to be 84% (predicted) at the optimum level of sucrose (11.73 g/L), ammonium sulfate (1.26 g/L), pH (5.71), and temperature (28.26 °C). Further, the validation results confirmed that the predicted values are in good agreement with the experimental results for RR120 degradation by
A. flavus
(86%),
A. fumigatus
(84%),
A. niger
(85%), and
A. terreus
(86%). The metabolic product of RR120 after biodegradation by different
Aspergillus
species was identified as sodium 2-aminobenzenesulfonate. The present study suggests that
Aspergillus
species are good candidates for azo dye-loaded effluent treatment.