Eco-Friendly Enhancement of Crude Oil Degradation in Water with Soursop Peel Biocarrier

ABSTRACT: his study investigated the potential of soursop peel as an environmentally friendly biocarrier for the remediation of crude oil-contaminated water using Aspergillus niger. The biocarrier was characterized before and after application to determine its macro- and micronutrient composition, including carbon, nitrogen, phosphorus, potassium, calcium, protein, cellulose, lignin, and carbohydrates, all of which support microbial metabolism. Fourier Transform Infrared (FTIR) spectroscopy confirmed the presence of functional groups that enhance microbial colonization and activity. Bioremediation experiments were performed in microcosms containing crude oil, water, A. niger, and soursop peel biocarrier. Process conditions, time, pH, dosage, and temperature were optimized using a Greco–Latin square design and Box–Behnken response surface methodology (RSM) to evaluate their effects on total petroleum hydrocarbon (TPH) removal. Results showed that the soursop peel biocarrier significantly improved microbial degradation, achieving an optimal removal efficiency of 64.90% TPH at 29 days under conditions of 31 °C, pH 8.5, and 7 g dosage. Compared with conventional inorganic fertilizers, soursop peel is a sustainable nutrient source that reduces environmental risks while enhancing degradation performance. Overall, the findings demonstrate that agricultural residues such as soursop peel can serve as effective, low-cost, and eco-friendly biocarriers for improving the bioremediation of crude oil-polluted aquatic environments.