Bacterial and archaeal community composition along the water column and in the sediment of Averno lake as revealed by 16S rRNA and [FeFe]-hydrogenases genes-based approaches
Author(s)
Paganin, Patrizia
Date Issued
March 15, 2010
Type
Doctoral Thesis
Abstract
The diversity of lake microbial communities has been investigated for many years using
methods based on isolation of microorganisms on culture media. However, as the proportion
of cells from environmental samples which can be cultured is estimated to be 0.1% or at most 10% of the total population, this method provides partial data concerning the composition of these communities. Recent advances in the field of molecular biology (extraction of nucleic acids, polymerase chain reaction (PCR) amplification, fingerprinting methods) allowed the
development of techniques which no longer require the isolation and cultivation of bacteria.
Denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA gene fragments
has been widely used to assess the diversity of complex microbial communities. Several
cultivation-independent studies of microbial diversity in sediments and water column of lakes have been conducted, but the importance and role of microorganisms in these ecosystems require further investigation, especially with respect to their potentially important
partecipation in the significant biogeochemical cycling of elements such as carbon and nitrogen. For this purpose it could be also useful to characterize bacterial populations with
specific metabolic activities, such as nitrification/denitrification, sulfate reduction, methane production and hydrogen production, on the basis of their functional genes.
In particular, in the last years, hydrogen-evolving microorganisms have attracted much
attention due to their potential in biological hydrogen production from renewable biomass.
Since it was demonstrated that lake sediment represents an efficient inoculum for an
appreciable hydrogen production (Kawagoshi et al., 2005), it is useful to assess the the
diversity of H2 producing bacteria naturally occurring in this habitat.
In the present study PCR-DGGE technique was employed to assess the microbial
diversity along the water column of Lake Averno in relation to environmental parameters, and to investigate the bacterial community composition of its superficial sediment. Moreover, the diversity of H2 producing bacteria from lake sediment was assessed by PCR amplification,
cloning and sequencing of the FHG fragments.
Additional information
Dottorato di ricerca in Ecologia e gestione delle risorse biologiche
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