Metabolism of Long-Chain Fatty Acids (LCFAs) in Methanogenesis

Sharma, Parinita; Khardenavis, Anshuman A.; Purohit, Hemant J.

doi:10.1007/978-81-322-2598-0_16

Cited by 9 publications

(2 citation statements)

References 47 publications

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“…Efficient AD of long chain fatty acids (LCFAs) is needed for the valorization of complex wastes such as lipid-containing wastes, which has higher CH 4 potential than that produced from other substrates such as proteins and carbohydrates [8][9][10]. However, LCFAs can inhibit and/or destabilize the AD process by adsorbing onto the surface of methanogenic consortia, inhibiting nutrient transfer [11,12]. To alleviate the inhibition, the addition of chemicals such as CaCl 2 and NaOH has been attempted to increase LCFAs' solubilization [13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Enhanced Anaerobic Digestion of Long Chain Fatty Acid by Adding Magnetite and Carbon Nanotubes

Mostafa

Song

et al. 2020

Microorganisms

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This study investigated the impact of stimulating direct interspecies electron transfer (DIET), by supplementing nano-sized magnetite (nFe3O4, 0.5 g Fe/g VSS) and carbon nanotubes (CNT, 1 g/L), in anaerobic digestion of oleic acid (OA) at various concentrations (0.10–4.00 g chemical oxygen demand(COD)/L). Both supplementations could enhance CH4 production, and its beneficial impact increased with increased OA concentration. The biggest improvements of 114% and 165% compared to the control were achieved by nFe3O4 and CNT, respectively, at OA of 4 g COD/L. The enhancement can be attributed to the increased sludge conductivity: 7.1 ± 0.5 (control), 12.5 ± 0.8 (nFe3O4-added), and 15.7 ± 1.1 µS/cm (CNT-supplemented). Dissolved iron concentration, released from nFe3O4, seemed to have a negligible role in improving CH4 production. The excretion of electron shuttles, i.e., humic-like substances and protein-like substances, were found to be stimulated by supplementing nFe3O4 and CNT. Microbial diversity was found to be simplified under DIET-stimulating conditions, whereby five genera accounted for 88% of the total sequences in the control, while more than 82% were represented by only two genera (Methanotrix concilli and Methanosarcina flavescens) by supplementing nFe3O4 and CNT. In addition, the abudance of electro-active bacteria such as Syntrophomonas zehnderi was significantly increased from 17% to around 45%.

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Section: Introductionmentioning

confidence: 99%

Enhanced Anaerobic Digestion of Long Chain Fatty Acid by Adding Magnetite and Carbon Nanotubes

Mostafa

Song

et al. 2020

Microorganisms

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“…Specific values for elemental sulfur-or thiosulfate-reducing cultures are not reported. As a second explanation, the accumulation of nondegraded LCFA in the cultures can also be a key factor for growth and activity limitation in methanogenic cultures (Pereira et al, 2005;Sharma et al, 2015). The adsorption of LCFA on the cell surface (Figure 8) is a possible explanation for physical inhibition of the bacterial community (Pereira et al, 2005).…”

Section: -Fed Sbrsmentioning

confidence: 99%

Long Chain Fatty Acid Degradation Coupled to Biological Sulfidogenesis: A Prospect for Enhanced Metal Recovery

Florentino

Costa

et al. 2020

Front. Bioeng. Biotechnol.

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This research assessed the microbiological suitability of oleate degradation coupled to sulfidogenesis by enriching communities from anaerobic sludge treating dairy products with S 0 , SO 2− 3 , SO 2− 4 , and S 2 O 2− 3 as electron acceptors. The limiting factor hampering highly efficient oleate degradation was investigated in batch reactors. The best sulfidogenic performance coupled to specialization of the enriched bacterial community was obtained for S 0-and S 2 O 2− 3-reducing enrichments, with 15.6 (± 0.2) and 9.0 (± 0.0) mM of sulfide production, respectively. Microbial community analyses revealed predominance of Enterobacteraceae (50.6 ± 5.7%), Sulfurospirillum (23.1 ± 0.1%), Bacteroides (7.5 ± 1.5%) and Seleniivibrio (6.9 ± 1.1%) in S 0-reducing cultures. In S 2 O 2− 3-reducing enrichments, the genus Desulfurella predominated (49.2 ± 1.2%), followed by the Enterobacterales order (20.9 ± 2.3%). S 0-reducing cultures were not affected by oleate concentrations up to 5 mM, while S 2 O 2− 3-reducing cultures could degrade oleate in concentrations up to 10 mM, with no significant impact on sulfidogenesis. In sequencing batch reactors operated with sulfide stripping, the S 0reducing enrichment produced 145.8 mM sulfide, precipitating Zn as ZnS in a separate tank. The S 2 O 2− 3 fed bioreactor only produced 23.4 mM of sulfide precipitated as ZnS. The lower sulfide production likely happened due to sulfite toxicity, an intermediate of thiosulfate reduction. Therefore, elemental sulfur reduction represents an excellent alternative to the currently adopted approaches for LCFA degradation. To the best of our knowledge, this is the first report of oleate degradation with the flux of electrons totally diverted toward sulfide production for metal precipitation, showing great efficiency of LCFA degradation coupled to high levels of metals precipitated as metal sulfide.

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