Humic Acid-Like and Fulvic Acid-Like Inhibition on the Hydrolysis of Cellulose and Tributyrin

Fernandes, Tânia V.; Lier, J.B. van; Zeeman, G.

doi:10.1007/s12155-014-9564-z

Cited by 84 publications

(49 citation statements)

References 23 publications

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“…Humic acid (HA) is a product of the decay and/or polymerisation of organic matter and behaves like a weak acid polyelectrolyte (Veeken and Hamelers, 1999). Previous studies have reported possible inhibition by humic substances within the concentration range 0.5 to 5.0 g L-1 (Fernandes et al, 2014;Ghasimi et al, 2016).…”

Section: Inhibitionmentioning

confidence: 97%

“…For example, a manure digester was known to be inhibited by ammonia (Yenigun et al 2013) and/or humic acid (HA) (Brons et al, 1985;Fernandes et al, 2014), which is considered highly relevant for solid manure residues. Yet relevant studies have largely focused on the inhibitory effect of ammonia (Yenigun et al 2013) with much less attention given to HA (Brons et al, 1985;Fernandes et al, 2014). This is despite the observations of previous works that suggested that HA could inhibit substrate solubilisation (Brons et al, 1985;Fernandes et al, 2014).…”

Section: Research Motivationmentioning

confidence: 99%

“…Yet relevant studies have largely focused on the inhibitory effect of ammonia (Yenigun et al 2013) with much less attention given to HA (Brons et al, 1985;Fernandes et al, 2014). This is despite the observations of previous works that suggested that HA could inhibit substrate solubilisation (Brons et al, 1985;Fernandes et al, 2014). Prior studies have focussed on physicochemical methods to mitigate HA inhibition, such as precipitation or complexing with metal salts (Azman et al, 2015;Brons et al, 1985) or ion exchange (Boyer and Singer, 2006;Fearing et al, 2004).…”

Section: Research Motivationmentioning

confidence: 99%

“…The digestion of solid manure residues could also be inhibited by humic substances (Fernandes et al, 2014). Humic acid (HA) is a product of the decay and/or polymerisation of organic matter and behaves like a weak acid polyelectrolyte (Veeken and Hamelers, 1999).…”

Section: Inhibitionmentioning

confidence: 99%

“…Hydrolysis can be inhibited by HA (Brons et al, 1985;Fernandes et al, 2014) and mechanistic hypotheses have been proposed for this inhibition, including:…”

Section: Inhibitionmentioning

confidence: 99%

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Anaerobic treatment of solid manure residues

Yap¹

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Spent bedding, which is a mix of bedding stubble, faeces, urine, spilt water and animal feed, is a major by-product of livestock farming in Australia and the United States. In Australia, such residues are stockpiled for passive composting prior to land spreading to harness the nutrient value. Key concerns are uncontrolled greenhouse gas emissions, odour, losses of nutrients, and the potential for ground and surface water contamination. A sustainable management alternative is anaerobic digestion (AD), whereby organic matter in the spent bedding is converted into useable methane energy and nutrients are mobilized for subsequent recovery. However, AD technology is not currently available in Australia at a sufficiently low cost and low level of complexity for on-farm adoption. In addition, the AD characteristics of solid manure residues are not well understood, posing significant uncertainty for AD design and optimization. In response, this thesis examines a leachbed AD approach, which is particularly suitable for high solids wastes such as spend bedding, and can be cost-effective and simple to construct and operate.A pilot scale (200 L) leachbed system was constructed and operated. Spent bedding was collected from Australian piggeries and wetted with water leachate in the enclosed leachbed via two distinct operating modes: trickling and flood-and-drain. The water leachate was heated in both configurations, aimed at a 37 o C operating temperature. Results showed comparable methane recovery for both the trickling and flood-and-drain modes at 50% of the biochemical methane potential (B0 = 195 -218 L CH4 kg VSfed -1 ) in both cases. This indicated that AD performance was insensitive to the mode of leachate flow. However, the flood-and-drain leachbed did mobilise more particulates into the leachate than the trickling leachbed, which could cause a materials-handling problem with pumping of leachate onfarm. Inoculation with solid digestate from a previous leachbed (inoculum-to-substrate ratio of 0.22 on a VS basis) hastened the AD start-up, but methane recovery remained at 50 % of the Bo. Post-digestion testing indicated that methane recovery was limited by insufficient indigenous inoculum and/or by chemical inhibition.To clarify the effects of operating conditions on AD performance at high solids content, a series of batch tests were performed at smaller laboratory scale. These tested the viability of indigenous inoculum in spent bedding (from the manure component), together with the effects of operating temperature and solids concentration. Results showed that spent bedding actually did have sufficient indigenous inoculum to recover the full Bo of the spent bedding. However, to operate at higher solid loading (≥ 10 % TS content) and higher II temperatures (55 ºC), methanogenic activity could be boosted by inoculation with leachate and/or solid digestate from a former leachbed batch. The use of leachate as an inoculum would preserve leachbed volume for fresh waste and easier handling.Chemical analysis of digestat...

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Section: Inhibitionmentioning

confidence: 97%

Section: Research Motivationmentioning

confidence: 99%

Section: Research Motivationmentioning

confidence: 99%

Section: Inhibitionmentioning

confidence: 99%

“…Hydrolysis can be inhibited by HA (Brons et al, 1985;Fernandes et al, 2014) and mechanistic hypotheses have been proposed for this inhibition, including:…”

Section: Inhibitionmentioning

confidence: 99%

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Anaerobic treatment of solid manure residues

Yap¹

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Rapid anaerobic digestion of organic solid residuals for biogas production using flocculating bacteria and membrane bioreactors – a critical review

Wikandari

Taherzadeh

2019

Biofuels Bioprod Bioref

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Anaerobic digestion (AD) is an attractive and sustainable alternative for stabilizing solid organic waste and producing biogas or biomethane. However, it is carried out by slow‐growing bacteria and archaea and it normally demands a hydraulic retention time (HRT) of 20–60 days in the bioreactor. Although high‐rate AD methods and technologies have been developed, they are normally applied to liquid wastes such as wastewater. In this work, the theory and latest developments in high‐rate digestion of organic solid wastes are reviewed. The process is accomplished by running the AD in a two‐stage operation. The first stage involves dissolving the solid materials in water, using robust hydrolytic bacteria. The effluent is then filtered to remove any undigested material, which in some cases contains inhibitory compounds. The filtrate is then fed to bioreactors containing high cell density ADs such as flocculating bacteria (granules) or membrane bioreactors (MBR) to protect the sensitive and very slow‐growing methanogen. Different approaches to overcoming problems faced in the first stage of digestion are proposed in this review. These problems include slow digestion of lignocellulosic biomass or failure of digestion due to inhibition problems for feedstocks containing toxic compounds, and rapid acidification for easily degradable substrates. The principle, technology, benefits and drawbacks, and factors affecting the efficacy of each type of high cell‐density reactor are presented. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

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Humic substances reduce ruminal methane production and increase the efficiency of microbial protein synthesisin vitro

et al. 2018

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BACKGROUND: In ruminants, enteric CH 4 represents a major energy loss for the host and is a potent greenhouse gas that contributes to climate change. Previous studies have shown that humic substances (HS) may have beneficial effects on livestock nutrition. The present study investigated the effects of HS on in vitro CH 4 production and rumen fermentation. RESULTS: Total gas production was linearly increased with increasing HS after 12 h of incubation, although it was unaffected after 24 and 48 h. Increasing HS linearly decreased CH 4 at all time points. Increasing HS linearly decreased NH 3 -N concentration and the molar proportion of acetate at 12 h, whereas the efficiency of microbial protein (MP) production and total dry matter digestibility (TDMD) linearly increased, with starch digestion (SD) responding quadratically. After 48 h, HS linearly increased MP and TDMD, with neutral detergent fibre digestibility responding quadratically.CONCLUSION: Inclusion of HS effectively reduced CH 4 production and increased substrate disappearance and the efficiency of microbial protein synthesis in vitro. However, its effect on in vivo CH 4 production, rumen fermentation and ruminant production requires further investigation.

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Humic Acid-Like and Fulvic Acid-Like Inhibition on the Hydrolysis of Cellulose and Tributyrin

Cited by 84 publications

References 23 publications

Anaerobic treatment of solid manure residues

Anaerobic treatment of solid manure residues

Rapid anaerobic digestion of organic solid residuals for biogas production using flocculating bacteria and membrane bioreactors – a critical review

Humic substances reduce ruminal methane production and increase the efficiency of microbial protein synthesisin vitro

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