Effect of ethanol pre-fermentation and inoculum-to-substrate ratio on methane yield from food waste and distillers’ grains

Wu, Chuanfu; Wang, Qunhui; Yu, Miao; Zhang, Xiao; Song, Na; Chang, Qiang; Gao, Ming; Sonomoto, Kenji

doi:10.1016/j.apenergy.2015.04.081

Cited by 72 publications

(32 citation statements)

References 33 publications

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“…). In batch systems, this curve typically shows high initial rates followed by a decline and then a second raise with a final drop during substrate exhaustion …”

Section: Resultsmentioning

confidence: 99%

“…In batch systems, this curve typically shows high initial rates followed by a decline and then a second raise with a final drop during substrate exhaustion. 17 In the landfill solid sample, the presence of a lag phase and a positive response to an increase in inoculum proportion suggests low microbial abundance of key microorganisms as methanogens or that a higher proportion of solids that characterized this sample (Table 2) were beneficial to improve the buffering capacity and nutrient supply of the system. 25 However, at I:S = 3, higher amounts of age-related substances such as humic acids 14 might have negatively impacted microbial activity ( Fig.…”

Section: Biochemical Methane Potential Assaymentioning

confidence: 95%

“…6 Concurrently, in easily degradable feedstocks such as food waste, acidification could rapidly take place by the accumulation of VFAs produced by acidogens inhibiting methanogens when the buffering capacity of the system is consumed. 17 Although the pH was adjusted at the start of the assay, a slight decrease in pH was observed in the sludge as the I:S ratio increased (Table 3). However, if VFAs are generated at a rate at which they could be continuously consumed by methanogens, this condition is reverted; 17 this seemed to occur by the diauxic behaviour observed in daily CH 4 yield at the optimal I:S = 1 (Fig.…”

Section: Biochemical Methane Potential Assaymentioning

confidence: 99%

“…An imbalance between acidogenesis and acetogenesis can result in volatile fatty acid (VFA) accumulation and a consequent pH drop that compromises methanogen activity. 17,18 Hence, understanding the variations in microbial community structure is essential for biogas production. Metagenomic analysis by Next Generation Sequencing has gained attention as a high-throughput culture-independent tool for studying microbial communities.…”

Section: Introductionmentioning

confidence: 99%

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Methane potential and metagenomics of wastewater sludge and a methane‐producing landfill solid sample as microbial inocula for anaerobic digestion of food waste

Sillas‐Moreno

Senés‐Guerrero

Pacheco

et al. 2018

J of Chemical Tech & Biotech

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BACKGROUND Anaerobic digestion of food waste is influenced by the selection of an adequate microbial inoculum. In this study, wastewater sludge, a methane (CH4)‐producing landfill solid sample and the combination of both [1:1 volatile solid (VS)] were tested as inocula to treat food waste modelled to the Mexican diet. Hence, biochemical methane potential assays at inoculum to substrate (I:S) ratios of 1–3 and each inoculum metagenome were determined. RESULTS Methane production was optimal at I:S = 1 for sludge and the combined inoculum, whereas for landfill solid sample increasing the proportion of inoculum was beneficial up to I:S = 2. The landfill solid sample produced more CH4 than commonly used sludge (311.5 ± 11.1 and 282.5 ± 18.1 mL CH4 g−1 VS, respectively) but presented an adaptation phase (four days). Combining inocula (I:S = 1) produced a synergistic effect in CH4 yield (374.5 ± 10.5 mL CH4 g−1 VS), biogas quality (58.0 ± 0.3% CH4) and COD removal (90.0 ± 0.6%) without start‐up time. Moreover, an enriched microbial community high in Archaea and Bacteria was observed, probably because of the incorporation of predominant members of each inoculum (Bacteroidetes, Firmicutes and Euryarchaeota in sludge, and Proteobacteria and Actinobacteria in landfill solid sample). Archaea was represented mainly by the genus Methanosaeta (order Methanosarcinales), suggesting that methanogenesis occurred by the acetoclastic pathway. CONCLUSION Food waste from Mexican diet was a suitable feedstock for biogas generation. Optimal conditions were observed when combining both inocula. Further studies on population dynamics during digestion would help understand the synergistic effect for effective industrial application. © 2018 Society of Chemical Industry

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“…). In batch systems, this curve typically shows high initial rates followed by a decline and then a second raise with a final drop during substrate exhaustion …”

Section: Resultsmentioning

confidence: 99%

Section: Biochemical Methane Potential Assaymentioning

confidence: 95%

Section: Biochemical Methane Potential Assaymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Methane potential and metagenomics of wastewater sludge and a methane‐producing landfill solid sample as microbial inocula for anaerobic digestion of food waste

Sillas‐Moreno

Senés‐Guerrero

Pacheco

et al. 2018

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

show abstract

“…As an important part of biological pretreatment, ethanol pre-fermentation has become a popular research topic in recent years. Wu et al found that ethanol pre-fermentation effectively alleviated the inhibition of acidification, greatly reduced the lag period and significantly stimulated the growth of methanogens [15]. Although adding sodium hydroxide or bicarbonate to the AD system is the most direct and effective approach to control the pH of the system [16,17], these methods lead to excessive sodium ion accumulation and AD system inhibition.…”

Section: Introductionmentioning

confidence: 99%

Effect of yeast addition on the biogas production performance of a food waste anaerobic digestion system

Gao

Zhang

et al. 2020

R. Soc. open sci.

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Food waste contains numerous easily degradable components, and anaerobic digestion is prone to acidification and instability. This work aimed to investigate the effect of adding yeast on biogas production performance, when substrate is added after biogas production is reduced. The results showed that the daily biogas production increased 520 and 550 ml by adding 2.0% (volatile solids; VS) of activated yeast on the 12th and 37th day of anaerobic digestion, respectively, and the gas production was relatively stable. In the control group without yeast, the increase of gas production was significantly reduced. After the second addition of substrate and yeast, biogas production only increased 60 ml compared with that before the addition. After fermentation, the biogas production of yeast group also increased by 33.2% compared with the control group. Results of the analysis of indicators, such as volatile organic acids, alkalinity and propionic acid, showed that the stability of the anaerobic digestion system of the yeast group was higher. Thus, the yeast group is highly likely to recover normal gas production when the biogas production is reduced, and substrate is added. The results provide a reference for experiments on the industrialization of continuous anaerobic digestion to take tolerable measures when the organic load of the feed fluctuates dramatically.

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Kinetic analysis of the methanization of the byproducts from OFMSW fermentation

Jojoa-Unigarro

González‐Martínez

2021

J of Chemical Tech & Biotech

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BACKGROUND During anaerobic digestion of wastes, volatile fatty acid (VFA) production has been studied, but little attention has been paid to alcohols and lactic acid. Thermodynamically, lactic acid and alcohols are better substrates to produce methane than other VFA. This research identified the metabolites produced during the fermentation of the organic fraction of municipal solid waste and studied their methanization in a second stage. Analysis of the methane production curves is provided and explained according to Gibbʼs free energy of acetogenesis and methanogenesis. Based on the Michaelis–Menten model, a kinetic analysis is presented. RESULTS The specific methane production of the identified acids and alcohols are acetic acid, 343 NL/kgCOD; ethanol, 296; methanol, 181; butyric acid, 108; lactic acid, 64. Lactic and butyric acids present a long adaptation phase followed by a fast and short methane production. Acetic acid and ethanol finished the reaction in less than 16 h. The highest methane production rates (Vmax) were for butyric acid, methanol, and ethanol with 2136, 1934, and 1928 NmL L–1, respectively. The best affinity (lowest Km) values were for acetic and lactic acids and ethanol with 1.2, 1.9, and 2.0 gCOD L–1. CONCLUSION Together, acetic acid and ethanol represent 92% of all fermentation products. No endogenous methane production was observed during the methanization from acetic acid and ethanol. The highest specific methane production belongs to acetic acid (98% of the theoretical) and the lowest corresponds to lactic acid. Except for propionic acid, the methanization of the selected substrates follows the Michaelis and Menten model. © 2021 Society of Chemical Industry (SCI).

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Effect of ethanol pre-fermentation and inoculum-to-substrate ratio on methane yield from food waste and distillers’ grains

Cited by 72 publications

References 33 publications

Methane potential and metagenomics of wastewater sludge and a methane‐producing landfill solid sample as microbial inocula for anaerobic digestion of food waste

Methane potential and metagenomics of wastewater sludge and a methane‐producing landfill solid sample as microbial inocula for anaerobic digestion of food waste

Effect of yeast addition on the biogas production performance of a food waste anaerobic digestion system

Kinetic analysis of the methanization of the byproducts from OFMSW fermentation

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