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Taxonomic identification of three newly isolated Antarctic fungal strains by their 18S rDNA sequences revealed their affiliation with Aspergillus fumigatus. Phenol (0.5 g/l) as the sole carbon source was completely degraded by all strains within less than two weeks. Intracellular activities of three key enzymes involved in the phenol catabolism were determined. Activities of phenol hydroxylase (EC 1.14.13.7), hydroquinone hydroxylase (EC 1.14.13.x), and catechol 1,2-dioxygenase (EC 1.13.11.1) varied significantly between strains. The rates of phenol degradation in the three strains correlated best with the activity of catechol 1,2-dioxygenase. Six pairs of oligonucleotide primers were designed on the basis of the Aspergillus fumigatus Af293 genome sequence (NCBI Acc. No. XM_743491.1) and used to amplify phenol hydroxylase-related gene sequences. DNA sequences of about 1200 bp were amplified from all three strains and found to have a high degree of sequence identity with the corresponding gene of Aspergillus fumigatus Af293.

Most industrial wastes contain different organic mixtures, making important the investigation on the microbial destruction of composite substrates. The capability of microbes to remove harmful chemicals from polluted environments strongly depends on the presence of other carbon and energy substrates. The effect of mixtures of phenol- and methyl-substituted phenols (o-, m-, p-cresol) on the growth behaviour and degradation capacity of Trichosporon cutaneum strain was investigated. The cell-free supernatants were analysed by HPLC. It was established that the presence of o-, m- and p- cresol has not prevented complete phenol assimilation but had significant delaying effect on the phenol degradation dynamics. The mutual influence of phenol and p-cresol was investigated. We developed the kinetic model on the basis of Haldane kinetics, which used model parameters from single-substrate experiments to predict the outcome of the two-substrate mixture experiment. The interaction coefficients indicating the degree to which phenol affects the biodegradation of p-cresol and vice versa were estimated. Quantitative estimation of interaction parameters is essential to facilitate the application of single or mixed cultures to the bio-treatment of hazardous compounds.

Trametes versicolor 1 was shown to grow on phenol as its sole carbon and energy source. The culture growth and degradation ability dependence on culture medium pH value was observed. The optimal pH value of a liquid Czapek salt medium was 6.5. The investigated strain utilized completely 0.5 g/l phenol in 6 days. The dynamics of the phenol degradation process was investigated. The process was characterized by specific growth rate micromax 0.33 h(-1), metabolic coefficient k=4.4, yield coefficient Yx/s=0.23 and rate of degradation Q=0.506 h(-1). The intracellular activities of phenol hydroxylase (0.333 U/mg protein) and cis,cis-muconate lactonizing enzyme (0.41 U/mg protein) were demonstrated for the first time in this fungus. In an attempt to estimate the occurrence of gene sequences in T. versicolor 1 related to phenol degradation pathway a dot blot analysis with total DNA isolated from this strain was performed. Two synthetic oligonucleotides were used as hybridizing probes. One of the probes was homologous to the 5'end of phyA gene coding for phenol hydroxylase in Trichosporon cutaneum ATCC 46490. The other probe was created on the basis of cis,cis-muconate lactonizing enzyme coding gene in T. cutaneum ATCC 58094. The results of these investigations showed that T. versicolor 1 may carry genes similar to those of Trichosporon cutaneum capable to degrade phenol.