PAH degrading bacterial consortium: "In silico" study of gene products related to the PAH degradation pathway

MORELLI IRMA S; MACCHI MARIANELA; COPPOTELLI BIBIANA M.

Trieste

Workshop; Joint ICGEB-ICTP-APCTP Workshop on Systems Biology and Molecular Economy of Microbial; 2017

International Centre for Genetic Engineering and Biotechnology

We obtained a natural PAH-degrading consortium (CON) from a chronically PAH contaminated soil. The taxonomic composition and the diversity of the bacterial microbiomes of CON, were profiled using pyrosequencing. Then we isolated 4 strains: Sphingobium sp. (AM), Pseudomonas sp. (T y Bc-h) and Enterobacter sp. (B).The aims of this work is present the analysis of sequencing and partial assembly of the genomes of the isolated strains in which are identified in silico coding genes related to PAH degradation pathways. This was correlated with studies in pure culture to attempt to elucidate its functionality within the bacterial consortium CON.The genomic sequences were obtained using the whole genome shotgun by an Illumina HiSeq1500 sequencer.Genes for the initial dioxygenase enzymes genes and other dioxygenases from the Upper and Lower pathway in the PAH degdradation were found in the 4 genomes. However, not all the strains had the enzymes for complete pathway, and only AM strain was capable of degrading phenanthrene in single cultures.Although T and Bc showed growth in F, AHN and salicylic acid.There are also transcriptional regulator gene products that control the expression of the catabolic pathways of the degradation of aromatic compounds, such as CatR and NTRC and others belonging to the families AraC, FNR, MarR and GntR.The in silico analysis of the genomes revealed that all the strains might produce PAH degradation pathway enzymes. However, in pure cultures only the AM strain was capable of degrading PAH or its intermediaries. Aromatic compounds degradation is more complex than can be inferred from the genes information which is present in a microbiome. There is a huge variety of regulatory mechanisms of the degrading gene expression which keep the information on how to regulate the gene expression within such complex and cooperative systems as consortium.