Biodegradation of Nile perch wastewater by Bacillus anthracis and Bacillus fusiformis consortium: potency for ecofriendly treatment and reutilization.

Abstract

Approximately 2 billion liters of Nile perch wastewater from fish processing industries are produced annually and conventionally treated contributing to pollution; and to date no any report about its biological treatment. In order to assess its eco-friendly treatment and recovery of high value bioactive compounds; an aerobic biodegradation of 200 mL of it by Bacillus fusiformis and Bacillus anthracis strains was carried out in a 0.5 L sterile flask in a shaking incubator (160 r.p.m) at 45°C. During biodegradation, removal of the COD activity occurred with the disappearance of fishy smell. The microbial consortium reduced the COD and the TN by 47.2% and 34.0%, respectively with the C/N ratio in the range of 5.4 to 7.0, presenting stable biodegradation. The 60 h culture supernatant showed high antioxidant activity determined by DPPH and ABTS assays, 78.9% and 92.5% respectively due to presence of produced low molecular weight compounds. The produced low molecular compounds were probably specific amino acids as determined by 2D-TLC. Moreover, the supernatant displayed significant potency on antimicrobial activity at 1170 µg/mL and 585 µg/mL against Vibrio vulnificus, a common disease causing bacteria, as potent source of antioxidants and antimicrobial substances. This is the first demonstration of its reutilization.

Keywords: Nile perch wastewater, Antioxidant, Antimicrobial, 2D-TLC, Biodegradation.