Simultaneous degradation of p-nitrophenol and phenol by a newly isolated Nocardioides sp.

A p-nitrophenol (PNP)- and phenol-mineralizing bacterium (strain NSP41) was isolated from an industrial wastewater and identified as a member of the g enus Nocardioides, PNP was degraded via a hydroquinone pathway, and phenol was degraded through a catechol pathway in strain NSP41, Both enzyme system s for the degradation of PNP and phenol were induced simultaneously in the presence of both compounds. Although both enzyme systems were induced at th e same time, PNP and phenol were degraded by the hydroquinone and catechol pathway, respectively. However, during the simultaneous degradation in the low phenol concentration, after the exhaustion of phenol, some PNP was tran sformed by the catechol pathway and 4-nitrocatechol was transiently accumul ated. Kinetically, the addition of phenol greatly enhanced the apparent PNP degradation rate, which may be due to the increased cell mass by the assim ilation of phenol.