[Co-metabolism of dual culture in the degradation of phenolic compounds]

Abstract

The biodegradation of phenol, m-cresol and 4-chlorophenol by the pure and mixed culture of Pseudomonas putida and Candida tropicalis was investigated. The results showed that,with the initial concentrations of 100, 50 and 60 mg x L(-1) for phenol, m-cresol and 4-chlorophenol, respectively,and an increase in the absolute value of the kinetic constant k of 19.0%, 2.6% and 46.4% for the degradation of phenol, m-cresol and 4-chlorophenol, respectively, was reached by dual culture compared with pure culture. The activity assays of phenol hydroxylase and catechol 1, 2-dioxygenase demonstrated phenol was degraded via the ortho-cleavage pathway in both of the two species. Further experiments via high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry techniques (LC-MS) suggested the degradation of three phenolic compounds could be accelerated due to co-metabolism by Pseudomonas putida of cis, cis-muconic acid, and 4-carboxymethylenebut-2-en-4-olide accumulated in phenol and 4-chlorophenol degradation, respectively, 3, 4-dihydroxybenzoic acid, 2-maleylacetate, and 3-oxoadipate in the degradation of m-cresol by Candida tropicalis in dual culture.