Characterization of benzoate degradation by newly isolated bacterium Pseudomonas sp. XP-M2

An effective benzoate-degradation strain XP-M2 belonging to the genus Pseudomonas, was newly isolated from aromatic compounds contaminated soils. The growing cells of strain XP-M2 completely degraded 10 g/L benzoate within 12 h, and the degradation efficiency was found to be higher than other reports. Catechol and cis,cis-muconic acid as the metabolic intermediates were identified by gas chromatography–high-resolution mass spectrometry, and the catA gene encoding catechol 1,2-dioxygenase in this strain was cloned and expressed in Escherichia coli, which indicated that benzoate degradation by Pseudomonas sp. XP-M2 was via the ortho-cleavage pathway. In addition, the Andrews model was used to describe the functional relationship between specific growth rate and benzoate concentrations with kinetics parameters: KS = 2.47 g/L, KI = 3.81 g/L.