Growth of Trametes Versicolor in Nitro and Hydroxyl Phenol Derivatives

ABSTRACT

This is the first report on the ability of Trametes versicolor to utilize hydroxyl and nitro aromatic compounds as a sole carbon source. The cultivation was carried out in Czapek salt medium supplemented with 0.5 g/l 2-,3-,4-nitrophenol as well as benzene-1,3-diol (resorcinol), benzene-1,2-diol (catechol) and benzene-1,4-diol (hydroquinone), respectively. The hydroxylated phenols were completely utilized for 80–96 hours. The best degradation of the investigated nitrophenols was registered with 2-nitrophenol. The strain was able to degrade it completely in 216 hours.

The dynamics of all degradation processes were investigated and characterized by specific growth rate (μ_max), metabolic coefficient (k) and rate of degradation (Q). The kinetic parameters established for the best utilized compounds were as follows: benzene-1,3-diol—μ_max = 0.065 h⁻¹, k = 9.0, Q = 0.075 h⁻¹; and 2-nitrophenol—μ_max = 0.048 h-¹, k = 8.5, Q = 0.033 h⁻¹. The intracellular phenol hydroxylase [EC 1.14.13.7], catechol-1,2-dioxygenase [EC 1.13.11.1], and cis, cis-muconate lactonizing enzyme [EC 5.5.1.5] activities were determined in cells cultivated in medium complemented with the best utilized compounds—resorcinol and 2-nitrophenol. The obtained data showed that the substrate specificity of the first enzyme—phenol hydroxylase, is decisive for the rate of degradation of the studied toxic aromatic compounds.

Keywords:

• Trametes versicolor
• phenol hydroxylase
• catechol-1,2-dioxygenase
• cis
• cis-muconate lactonizing enzyme
• nitro-and hydroxy-phenols