Electron donors for biological sulfate reduction

Decomposition and mineralization of aquatic humic substances (AHS) in treating landfill leachate using the Anammox process

“…It has been demonstrated that AHS can be serve as electron donors to be oxidized for Fe(III)-reducing microorganisms growing on electron acceptors, such as nitrate and fumarate (Lovley et al, 1999), indicating that AHS may play an important role as an electron donor in anaerobic environments. However, few studies have reported the role of sulfate as suitable electron acceptor to oxidize AHS in landfill leachate yet (Liamleam and Annachhatre, 2007). Results in this work certainly indicated the correlation between anaerobic oxidization of AHS and sulfate reduction, which should be established by the metabolic activities of the four strains.…”

“…In this study, despite the failure in the SRB isolation, the fact of sulfate reduction positively favored the deduction that sulfates functioned as electron receiver in the anaerobic respiration. Generally, low-MW and readily biodegradable organic compounds are suitable electron donors for sulfate reduction (Liamleam and Annachhatre, 2007), however, enriched bacterial cultures have been found to degrade and mineralize saturated aromatic or unsaturated non-aromatic hydrocarbons via sulfate reduction (Kniemeyer et al, 2003). In this study, there might be two kinds of sulfate reduction mechanisms in terms of different electron donors: (1) phenolic or other aromatic fraction in AHS was directly attacked as reducer, and (2) small size intermediates acted as terminal electron donors.…”

Comparison of Uasb and Fluidized-Bed Reactors for Sulfate Reduction

“…Furthermore, in the case of UASB reactors, the residence time must be larger than the generation time to avoid microorganism washout (during sulfidogenesis) (Kaksonen et al, 2004). Overall, the performance of anaerobic reactors treating high sulfate loading rates (SLR) is defined by: (i) substrate type (Liamleam and Annachhatre, 2007); (ii) COD.sulfate -1 ratio (Shayegan et al, 2005;Velasco et al, 2008); (iii) inoculum source and enrichment procedure (Mohan, 2005); (iv) pH values (Cao et al, 2009); competition among different groups of microorganisms (Dar et al, 2008;Zhao et al, 2008), and reactor configuration (Sahinkaya et al, 2007;Sheoran et al, 2010). Moreover, competition between sulfate-reducing bacteria (SRB) and methane-producing microorganisms (MPM) in anaerobic reactors is well documented (Bhattacharya et al, 1996;Harada et al, 1994;Omil et al, 1998), but the fermentative metabolism, which can also degrade low molecular weight carbon sources (Dinkel et al, 2010;Ren et al, 2007;Zhao et al, 2008), is less discussed in the context of continuous sulfate reduction.…”

Biotechnological aspects of sulfate reduction with methane as electron donor

“…Easily degradable bulk chemicals are therefore a better option. Such electron donors include hydrogen, synthesis gas, methanol, ethanol, acetate, lactate, propionate, butyrate, sugar, and molasses (Liamleam and Annachhatre 2007), many of which have been extensively investigated as electron donor for SR in bioreactors (Table 2). According to van Houten (1996) hydrogen is the best electron donor at large scale ([5-10 kmol SO 4 2-h -1 ), while ethanol is an interesting electron donor at smaller and middle scale.…”