Microbial ecology of biotechnological processes

Fraraccio, Serena (2015) Microbial ecology of biotechnological processes, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Scienze biochimiche e biotecnologiche, 27 Ciclo. DOI 10.6092/unibo/amsdottorato/6913.
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The investigation of phylogenetic diversity and functionality of complex microbial communities in relation to changes in the environmental conditions represents a major challenge of microbial ecology research. Nowadays, particular attention is paid to microbial communities occurring at environmental sites contaminated by recalcitrant and toxic organic compounds. Extended research has evidenced that such communities evolve some metabolic abilities leading to the partial degradation or complete mineralization of the contaminants. Determination of such biodegradation potential can be the starting point for the development of cost effective biotechnological processes for the bioremediation of contaminated matrices. This work showed how metagenomics-based microbial ecology investigations supported the choice or the development of three different bioremediation strategies. First, PCR-DGGE and PCR-cloning approaches served the molecular characterization of microbial communities enriched through sequential development stages of an aerobic cometabolic process for the treatment of groundwater contaminated by chlorinated aliphatic hydrocarbons inside an immobilized-biomass packed bed bioreactor (PBR). In this case the analyses revealed homogeneous growth and structure of immobilized communities throughout the PBR and the occurrence of dominant microbial phylotypes of the genera Rhodococcus, Comamonas and Acidovorax, which probably drive the biodegradation process. The same molecular approaches were employed to characterize sludge microbial communities selected and enriched during the treatment of municipal wastewater coupled with the production of polyhydroxyalkanoates (PHA). Known PHA-accumulating microorganisms identified were affiliated with the genera Zooglea, Acidovorax and Hydrogenophaga. Finally, the molecular investigation concerned communities of polycyclic aromatic hydrocarbon (PAH) contaminated soil subjected to rhizoremediation with willow roots or fertilization-based treatments. The metabolic ability to biodegrade naphthalene, as a representative model for PAH, was assessed by means of stable isotope probing in combination with high-throughput sequencing analysis. The phylogenetic diversity of microbial populations able to derive carbon from naphthalene was evaluated as a function of the type of treatment.

Tipologia del documento
Tesi di dottorato
Fraraccio, Serena
Dottorato di ricerca
Scuola di dottorato
Scienze biologiche, biomediche e biotecnologiche
Settore disciplinare
Settore concorsuale
Parole chiave
Microbial ecology; metagenomics; biotechnological process; bioremediation; aerobic cometabolism; chlorinated aliphatic hydrocarbons (CAHs); polycyclic aromatic hydrocarbons (PAHs); polyhydroxyalkanoates (PHA); denaturing gradient gel electrophoresis (DGGE); stable isotope probing (SIP).
Data di discussione
13 Aprile 2015

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