Insights into the genome and proteome of Sphingomonas paucimobilis strain 20006FA involved in the regulation of polycyclic aromatic hydrocarbon degradation

MACCHI M, MORELLI I.S.; MARÍA PÍA VALACCO, ; MAURO MARTINEZ; IRMA S. MORELLI; RICARDO MARTIN NEME TAUIL; COPPOTELLI B.

World Journal of Microbiology and Biotechnology

SPRINGER

Año: 2017

0959-3993

In order to study the mechanisms regulating the phenanthrenedegradation pathway and the intermediate-metabolite accumulation in strain Sphingomonas paucimobilis 20006FA, we sequenced the genome and comparedthe genome-based predictions to experimental proteomic analyses. Physiological studies indicated that the degradation involved the salicylate and protocatechuate pathways, reaching 56.3% after 15 days. Furthermore, the strain degraded other polycyclic aromatic hydrocarbons (PAH) such as anthracene (13.1%), dibenzothiophene (76.3%), and fluoranthene.The intermediate metabolite 1-hydroxy-2-naphthoic acid (HNA) accumulated during phenanthrene catabolism and inhibited both bacterial growth and phenanthrenedegradation, but exogenous-HNA addition did not affect further degradation. Genomic analysis predicted 126 putative genes encoding enzymes for all the steps of phenanthrene degradation, which loci could also participate in the metabolism of other PAH. Proteomic analysis identified enzymes involved in 19 of the 23 steps needed for the transformation of phenanthrene to trichloroacetic-acid intermediates that were upregulated in phenanthrenecultures relative to the levels in glucose cultures. Moreover, the protein-induction pattern was temporal, varying between 24 and 96 h during phenanthrene degradation, with most catabolic proteins being overexpressed at 96 h?e. g., the biphenyl dioxygenase and a multispecies (2Fe-2S)-binding protein. These results providedthe first clues about regulation of expression of phenanthrene degradative enzymes in strain 20006FA and enabled an elucidation of the metabolic pathway utilized by the bacterium. To our knowledge the present work represents the first investigation of genomic, proteomic, and physiological studies of a PAH-degrading Sphingomonas strain