ICBM-3 - 3rd International Conference on Biogas MicrobiologyLinear olefins with 16 to 18 carbon atoms are frequently used
as hydrophobic groups in oil soluble
surfactants and as lubricating fluids. The production of olefins in petrochemical plants generates olefin contaminated wastewater that can be treated anaerobically in methanogenic bioreactors, coupling
degradation to energy recovery. However, this conversion is generally slow, due to olefins ́ insolubility in
water and poor bioavailability for microorganisms. Addition of an easy degradable carbon source may
enhance the growth of hydrocarbon
degrading methanogenic communities. In this study, hexadecene
degradation by a methanogenic enrichment was stimulated by addition of yeast extract (0.5 g·L-1), lactate (4.5 mmol·L-1) or crotonate (4.5 mmol·L-1) as co-substrates. After stimulation with yeast extract or
lactate, the microbial communities were able to convert hexadecene to methane 5 and 2.5 times faster,
respectively, than non-stimulated cultures. Hexadecene conversion to methane was not enhanced by crotonate addition. Further incubations with fermented yeast extract did not improve methane production
from hexadecene, which suggests that the positive stimulatory effect of yeast extract was due to the
extra carbon source and not to the supply of essential co-factors. The microbial community composition
of the hexadecene degrading enrichments was studied by 16S rRNA sequencing. Bacteria from the Chloroflexi, Firmicutes, Proteobacteria(Deltaproteobacteria),
Spirochaetes, Synergistetes and Thermotogaephyla were identified, with
Syntrophobacterales,
Spirochaetales and Synergistales as the
most abundant orders. Hydrogenotrophic methanogens predominated over acetoclastic methanogens.
Currently the isolation and identification of key microbial players involved in hexadecene degradation are
ongoing. This study can be useful for improving the treatment of olefin contaminated wastewater using methanogenic conditionsinfo:eu-repo/semantics/publishedVersio
