Anaerobic Biodegradation of Eleven Aromatic Compounds to Methane

Abstract

A range of 11 simple aromatic lignin derivatives are biodegradable to methane and carbon dioxide under strict anaerobic conditions. A serum-bottle modification of the Hungate technique for growing anaerobes was used for methanogenic enrichments on vanillin, vanillic acid, ferulic acid, cinnamic acid, benzoic acid, catechol, protocatechuic acid, phenol, p-hydroxybenzoic acid, syringic acid, and syringaldehyde. Microbial populations acclimated to a particular aromatic substrate can be simultaneously acclimated to other selected aromatic substrates. Carbon balance measurements made on vanillic and ferulic acids indicate that the aromatic ring was cleaved and that the amount of methane produced from these substrates closely agrees with calculated stoichiometric values. These data suggest that more than half of the organic carbon of these aromatic compounds potentially can be converted to methane gas and that this type of methanogenic conversion of simple aromatics may not be uncommon.

p-Cresol biodegradation under denitrifying conditions: isolation of a bacterial coculture

“…The amended nitrate medium (ANM) used for culture enrichment was prepared according to Taylor et al [5] with the following modifications (per 1): KNO 3, 3.0 g; FeSO 4-7H20, 25.0 mg; CuSO4.5H20, 0.3 mg; NiCI2.6H20, 0.8 mg; yeast extract (Difco Detroit, MI), 10.0 mg; trace mineral solution [13], 15.0 ml and distilled water added to volume. The medium (pH 6.9) was dispensed under argon gas in 100 ml aliquots to argon-gassed serum bottles with butyl rubber stoppers (Bellco Glass, Vineland, N J) and autoclaved.…”

Anaerobic production and transformation of aromatic hydrocarbons and substituted phenols by ferulic acid-degrading BESA-inhibited methanogenic consortia

“…It has been shown that lignin-derived monoaromatic alcohols and acids can be completely degraded under methanogenic conditions [1][2][3][4][5]. The populations capable of such transformations are complex communities consisting of strictly anaerobic [6] and facultatively anaerobic fermentative bacteria [7,8], methanogens [5], and possibly also hydrogen-producing acetogens as an intermediary link between the two groups.…”

Methanogenic degradation of hydroquinone and catechol via reductive dehydroxylation to phenol

“…These substrates were therefore often considered recalcitrant in the absence of molecular oxygen [2], and catechol especially was found to be quite stable under anaerobic conditions [3,4]. Nonetheless, complete methanogenic degradation of phenolic and other aromatic compounds such as lignin monomers has been reported [5][6][7]. Methanogenic degradation of benzoate depends on a syntrophic co-operation of fermentative and hydrogen-oxidizing methanogenic bacteria [8,9], whereas trihydroxybenzoates and trihydroxybenzenes were fermented to acetate in pure culture [10].…”