Biodegradation of Acid Scarlet 3R by a New Salt-tolerant Strain Alcaligenes faecalis LJ-3: Character, Enzyme and Kinetics Analysis

Abstract

Alcaligenes faecalis LJ-3 is highly efficient in degrading various azo dyes (100 mg L–1). Almost 100 % degradation was observed within 16 h at the initial Acid Scarlet 3R concentrations of 1000 mg L–1 under the optimal conditions, which were: 1 g dextrin L–1, 3 g yeast extract L–1, NaCl ≤ 30 g L–1, pH 8.0 and 35–45 ºC. Azoreductase, laccase and NADH-DCIP (nicotinamide adenine dinucleotide-dichlorophenol indophenols) reductase were induced during the degradation of Acid Scarlet 3R. Kinetics study of degradation experiments approximated the first-order reaction. The maximum rate (Vmax) and substrate affinity constant (Ks ) were found to be 115.90 mg L–1 h–1 and 1193.23 mg L–1, respectively, using Michaelis-Menten kinetics. This work provides new data characterizing Acid Scarlet 3R degradation by bacteria, as well as practical application potential in biological treatment of industrial effluents containing various azo dyes.

Keywords

• Alcaligenes faecalis LJ-3
• degradation
• Acid Scarlet 3R
• enzyme
• kinetics