Accelerated methanogenesis from aliphatic and aromatic hydrocarbons under iron- and sulfate-reducing conditions

Abstract

The impact of four electron acceptors on hydrocarbon-induced methanogenesis was studied. Methanogenesis from residual hydrocarbons may enhance the exploitation of oil reservoirs and may improve bioremediation. The conditions to drive the rate-limiting first hydrocarbon-oxidizing steps for the conversion of hydrocarbons into methanogenic substrates are crucial. Thus, the electron acceptors ferrihydrite, manganese dioxide, nitrate or sulfate were added to sediment microcosms acquired from two brackish water locations. Hexadecane, ethylbenzene or 1-(13)C-naphthalene were used as model hydrocarbons. Methane was released most rapidly from incubations amended with ferrihydrite and hexadecane. Ferrihydrite enhanced only hexadecane-dependent methanogenesis. The rates of methanogenesis were negatively affected by sulfate and nitrate at concentrations of more than 5 and 1 mM, respectively. Metal-reducing Geobacteraceae and potential sulfate reducers as well as Methanosarcina were present in situ and in vitro. Ferrihydrite addition triggered the growth of Methanosarcina-related methanogens. Additionally, methane was removed concomitantly by anaerobic methanotrophy. ANME-1 and -2 methyl coenzyme M reductase genes were detected, indicating anaerobic methanotrophy as an accompanying process [Correction added 16 December after online publication: 'methyl coenzyme A' changed to 'methyl coenzyme M' in this sentence]. The experiments presented here demonstrate the feasibility of enhancing methanogenic alkane degradation by ferrihydrite or sulfate addition in different geological settings.

Anaerobic Degradation of Benzene and Polycyclic Aromatic Hydrocarbons

“…Dolfing et al [2009] have demonstrated that PAH metabolism coupled with methane production is thermodynamically feasible. Furthermore, microcosm experiments successfully showed the degradation of naphthalene, phenanthrene or methylnaphthalene under methanogenic conditions [Berdugo-Clavijo et al, 2012;Chang et al, 2006;Christensen et al, 2004;Maillacheruvu and Pathan, 2009;Siegert et al, 2011].…”

Methanogenic Hydrocarbon Degradation: Evidence from Field and Laboratory Studies

“…In the last decades, however, the topic has regained scientific attention and many studies attempting to explain the mechanistic aspects and to identify key microorganisms involved have been conducted. The conversion of hydrocarbons to methane has been extensively demonstrated in laboratory experiments ( table 2 ) Feisthauer et al, 2010;Gray et al, 2011;Gründger et al, 2015;Jiménez et al, 2012;Jones et al, 2008;Siegert et al, 2011;Tan et al, 2013;Wang et al, 2011;Zengler et al, 1999].…”

“…Generally, it has been considered that SO 4 2-concentrations above 50 μM cause methanogens to be outcompeted by sulfate-reducing bacteria using the same substrates more efficiently, whereas lower concentrations could even enhance methanogenesis [Siegert et al, 2011].…”

“…The occurrence of methanogenesis and the predominance of one or another of the methanogenic pathways in the environment may depend on a combination of factors such as temperature, CO 2 concentrations, salinity, pH, availability of electron acceptors and donors and nutrients, porosity and permeability, for example [Dolfing et al, 2008;Kotsyurbenko et al, 2007;Mayumi et al, 2011;Milkov, 2011;Schlegel et al, 2011;Siegert et al, 2011;Waldron et al, 2007]. From the distribution of biodegraded oils worldwide, it seems that reservoirs buried to temperatures of more than 80 ° C are effectively sterilized with regard to hydrocarbon degraders [Head et al, 2003;Wilhelms et al, 2001].…”

Extracellular Electron Transfer in in situ Petroleum Hydrocarbon Bioremediation

“…Biodegradation of petroleum hydrocarbons under iron-and manganese reducing conditions has been noted primarily for low molecular weight aromatic compounds. This includes benzene (Kunapuli et al, 2008), toluene Edwards and Grbic-Galic, 1994;Langenhoff et al, 1997;Lee et al, 2012), ethylbenzene (Siegert et al, 2011) and o-xylene (Edwards and Grbic-Galic, 1994) as well as phenol (Lovley et al, 1989), naphthalene and also liquid alkanes (Siegert et al, 2011).…”