Three types of phenol and p-cresol catabolism in phenol- and p-cresol-degrading bacteria isolated from river water continuously polluted with phenolic compounds

A total of 39 phenol- and p-cresol-degraders isolated From the river water continuously polluted with phenolic compounds of oil shale leachate were st udied. Species identification by BIOLOG GN analysis revealed 21 strains of Pseudomonas fluorescens (4, 8 and 9 of biotypes A, C and G, respectively), 12 of Pseudomonas mendocina, four of Pseudomonas putida biotype A1, one of Pseudomonas corrugata and one of Acinetobacter genospecies 15. Computer-ass isted analysis of rep-PCR fingerprints clustered the strains into groups wi th good concordance with the BIOLOG GN data. Three main catabolic types of degradation of phenol and p-cresol were revealed. Type I, or meta-meta type (15 strains), was characterized by meta cleavage of catechol by catechol 2 ,3-dioxygenase (C23O) during the growth on phenol and p-cresol. These strai ns carried C23O genes which gave PCR products with specific xy/E-gene prime rs. Type II, or ortho-ortho type (13 strains), was characterized by the deg radation of phenol through ortho fission of catechol by catechol 1,2-dioxyg enase (Cl2O) and p-cresol via ortho cleavage of protocatechuic acid by prot ocatechuate 3,4-dioxygenase (PC34O). These strains carried phenol monooxyge nase gene A hich gave PCR products with pheA-gene primers. Type III, or met a-ortho type (11 strains), was characterized by the degradation of phenol b y C23O and p-cresol via the protocatechuate ortho pathway by the induction of PC34O and this carried C23O genes which gave PCR products with C23O-gene primers, but not with specific xy/E-gene primers. In type III strains phen ol also induced the p-cresol protocatechuate pathway, as revealed by the in duction of p-cresol methylhydroxylase. These results demonstrate multiplici ty of catabolic types of degradation of phenol and p-cresol and the existen ce of characteristic assemblages of species and specific genotypes: among t he strains isolated From the polluted river water. (C) 2000 Federation of E uropean Microbiological Societies. Published by Elsevier Science B.V. All r ights reserved.