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Characterization of fatty acid-producing wastewater microbial communities using next generation sequencing technologies
Citation:
Santodomingo, J., V. Gomez-Alvarez, H. Ryu, A. Mondala, W. French, AND R. Hernandez. Characterization of fatty acid-producing wastewater microbial communities using next generation sequencing technologies. Presented at The 1st Waterloo International Conference of Sustainable Wastewater Treatment, Waterloo, ON, CANADA, August 08 - 09, 2012.
Impact/Purpose:
To inform the scientific community on research regarding biodiesel production from wastewater sludge
Description:
While wastewater represents a viable source of bacterial biodiesel production, very little is known on the composition of these microbial communities. We studied the taxonomic diversity and succession of microbial communities in bioreactors accumulating fatty acids using 454-pyrosequencing technology. Different parameters (e.g., pH, glucose feeding rate, aeration) were manipulated in separate bioreactors to establish the optimal lipid production yields. Maximum lipid content (20-40% dry weight) was achieved within 96h in the sequential batch reactor (SBR) and continuous (CONT) reactors. Controlling pH did not improve lipid yields while aeration triggered lipid accumulation. At the maximum biomass lipid content achieved, oleic acid (C18:1) comprised 40-60 % of the lipids compared, twice as much than in raw activated sludge. Analysis of 267,000 16S rDNA sequences indicated the presence of 37 Bacterial classes. In continuous and batch bioreactors (RAS) the bacterial diversity decreased drastically after 24h (i.e., from 500 to <100 species). In contrast, the diversity in SBR was maintained during the study, although changes in the distribution of species were observed. pH changed the abundance of Actinomycetales in pH 4 and 10 bioreactors and Rhodobacterales in the pH 7 bioreactor. Aeration also impacted community structure, with Actinomycetales and Myxococcales as the most abundant groups in RAS aerated bioreactors. The results of this study provide the molecular basis for the identification of potential biolipid-accumulating bacteria in wastewater. This information coupled with future metagenomic approaches will be used to better understand the genetic pathways associated with biodiesel production using wastewater microbial communities.