Synergistic degradation of 2-naphthol by Fusarium proliferatum and Bacillus subtilis in wastewater

2-Naphthol, which originates widely from various industrial activities, is toxic and thus harmful to human liver and kidney. A new compound biodegradation system was adopted to degrade 2-naphthol-contaminated wastewater. Enzymatic response to 2-naphthol biodegradation in the aqueous phase was also studied. As a co-metabolic substrate, salicylic acid could induce the two microorganisms to produce a large amount of degradation enzymes for 2-naphthol. The key enzymes were confirmed as polyphenol oxidase (PPO) and catechol 2,3-dioxygenase (C23O). The degradation extent of 2-naphthol, determined by high performance liquid chromatography (HPLC), was enhanced by nearly 15% on the 6th day after the addition of the co-metabolic substrate. The results obtained thus clearly indicated that the co-metabolic process was the most important factor affecting the degradation of the target contaminant. The optimal concentration of 2-naphthol was 150 mg; L-1, and the optimal pH value was 7.0. The degradation extent of 2-naphthol was further enhanced by nearly 10% after the addition of Tween 80, which increased the bioavailability of 2-naphthol. In a practical treatment of industrial wastewater from medical manufacture, the synergistic degradation system resulted in a high degradation efficiency of 2-naphthol although its lag time was a little long in the initial stage. (C) 2008 Elsevier B.V. All rights reserved.