Genomic analysis of the aromatic catabolic pathways from Silicibacter pomeroyi DSS-3

Abstract

Genomic analysis of the catabolic potentialities of Silicibacter pomeroyi DSS-3 against a wide range of natural aromatic compounds and sequence comparisons with the entire genome of this microorganism predicted the existence of at least seven main pathways for the conversion of the aromatic compounds to the intermediates which enter into TCA cycle, that is, the catechol (cat I and cat II genes) and protocatechuate (pca genes) branches of the β-ketoadipate pathway, the phenylacetate pathway (paa genes), the gentisate pathway (gtd genes), the homogentisate pathway (hmg/hppD genes), as well as the homoprotocatechuate pathway (hpc genes). Furthermore, the genes encoding those enzymes involved in the peripheral pathways leading to the β-ketoadipate central pathway were also mapped, i.e., 4-hydroxybenzoate (pob), benzoate (ben), quinate (qui), phenylpropenoid compounds (fcs, ech, vdh, cal, van, acd and act), tyrosine (hpp) and n-phenylalkanoic acids (fad). Evidences showed that S. pomeroyi DSS-3 have versatile abilities to the catabolism of aromatic compounds either in anaerobic or in aerobic pathway, suggesting such a strain might be a model of heuristic value for the study of the genomic organization, the evolution of genes, as well as the catalytic or transcriptional mechanisms of enzymes for aromatic degradation in marine bacteria. Further, it would provide new insights into the biodegradation of aromatic compounds in marine bacteria and marine environments.