Long-chain fatty acids (LCFA) are energy-rich
compounds, which are abundantly present in raw and
waste materials. Thus, wastewaters that contain LCFA
may yield high levels of methane in an anaerobic
digestion process. Biogas formation from LCFAcontaining
wastewater is a sustainable technology that
warrants further investigation, specifically in terms of
more fundamental microbiological aspects. The aim of
this work is to get more insights into the syntrophic
microbial communities that degrade LCFA
anaerobically. Bacterial shifts of a mesophilic sludge
incubated in the presence of palmitic, stearic or oleic
acid was estimated by means of automated ribosomal
intergenic spacer analysis (ARISA). Slightly
differences were observed between the communities
incubated with saturated LCFA (palmitic and stearic
acids) and the ones of the blank assay. On the other
hand, evident changes were found between ARISA
profiles of the communities that were incubated with
oleic acid and the ones obtained for the blank assay.
These results suggest that the microbial communities
that degrade saturated fatty acids are very close to each
other and different from the ones that degrade
unsaturated fatty acids
