Biodegradation of 2-naphthol and its metabolites by coupling Aspergillus nigerwith Bacillus subtilis
Shuyan Zang , Bin Lian , Juan Wang , Yanjie Yang
DOI:
Received August 23, 2009,Revised January 07, 2010, Accepted , Available online
Volume 22,2010,Pages 669-674
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To explore biodegradation of 2-naphthol and its metabolites accumulated in wastewater treatment, a series of bio-degradation
experiments were conducted. Two main metabolites of 2-naphthol, 1,2-naphthalene-diol and 1,2-naphthoquinone, were identified by
high-performance liquid chromatography with standards. Combining fungus Aspergillus niger with bacterium Bacillus subtilis in the
treatment enhanced 2-naphthol degradation e ciency, lowered the accumulation of the two toxic metabolites. There were two main
phases during the degradation process by the kinetic analysis: 2-naphthol was first partly degraded by the fungus, producing labile
and easily accumulated metabolites, and then the metabolites were mainly degraded by the bacterium, attested by the degradation
processes of 1,2-naphthalene-diol and 1,2-naphthoquinone as sole source of carbon and energy. Sodium succinate, as a co-metabolic
substrate, was the most suitable compound for the continuous degradation. The optimum concentration of 2-naphthol was 50 mg/L.
The overall 2-naphthol degradation rate was 92%, and the CODCr removal rate was 80% on day 10. These results indicated that
high degradation rate of 2-naphthol should not be considered as the sole desirable criterion for the bioremediation of 2-naphtholcontaminated
soils/wastewater.
