Inhibitory Effects of Phenolic Monomers on Methanogenesis in Anaerobic Digestion.
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Date
2013-01
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Abstract
Aims: The purpose of this study was to evaluate the inhibitory effects of phenolic
monomers on methanogenesis in anaerobic digestion and to assess the effect of hydroxyl
groups’ number of phenolic monomers (aromatic structure) on inhibition of methane
production by acetoclastic methanogens (archaea).
Study Design: Anaerobic digestion of pig manure, anaerobic toxicity essay, The effect of
the hydroxyl group’s number on the methanogenic toxicity as exhibited by monomeric
tannins, Correlation of the methanogenic toxicity (IC50) with aromatic compounds
hydrophobicity (logPoct), Correlation of the methanogenic toxicity (IC50) with Cresols boiling
point (bp).
Place and Duration of Study: Department of Chemistry, University of Kinshasa (DR
Congo), between September 2011 and May 2012.
Methodology: The toxicity to acetoclastic methanogenic bacteria was performed with the
standard method of serum bottles; digested pig manure was utilized as inoculums and
acetate as substrate. The methane gas volume produced was measured by serum bottles
liquid displacement systems (Mariotte flask system).
Results: The results of this study indicate that an increase in the number of hydroxyl
groups on the aromatic compound was associated with a decrease in the compound’s toxicity to methanogens (archea). The toxicity of various phenolic monomers are
decreasing in the following order: pyrogallol < hydroquinone < resorcinol < phenol <
benzene with 3172, 2745, 1725, 1249 and 209 mg/l IC50 values respectively. A significant
negative linear correlation between the toxicity of phenolic monomers together with the
reference compound (benzene) and their hydrophobicity was found. Moreover, a high
positive linear correlation has been found between the IC50 values of phenolic monomers
and their boiling temperatures.
Conclusion: The obtained results indicate that relationships exist between the phenolic
monomers structure and their inhibitory effects in methane biosynthesis. The analysis of
experimental results suggests that an increase in the number of hydroxyl groups on the
aromatic compounds was associated with a decrease in the phenolic monomers toxicity.
Description
Keywords
Phenolic monomers, tannin, methanogenesis, anaerobic digestion, toxicity, methanogens, archea, methane
Citation
Kayembe K, Basosila L, Mpiana P T, Sikulisimwa P C, Mbuyu K. Inhibitory Effects of Phenolic Monomers on Methanogenesis in Anaerobic Digestion. British Microbiology Research Journal. 2013 Jan; 3(1): 32-41.