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Cited by 90Anaerobic Digestion and Biogas ProductionRuminant Nutrition and Digestive PhysiologyBiofuel production and bioconversion

Improving aerobic stability and biogas production of maize silage using silage additives

Open access
Herrmann, Christiane, Idler, Christine, Heiermann, Monika·2015·Bioresource Technology
DOI 10.1016/j.biortech.2015.08.114
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Abstract

The effects of air stress during storage, exposure to air at feed-out, and treatment with silage additives to enhance aerobic stability on methane production from maize silage were investigated at laboratory scale. Up to 17% of the methane potential of maize without additive was lost during seven days exposure to air on feed-out. Air stress during storage reduced aerobic stability and further increased methane losses. A chemical additive containing salts of benzoate and propionate, and inoculants containing heterofermentative lactic acid bacteria were effective to increase aerobic stability and resulted in up to 29% higher methane yields after exposure to air. Exclusion of air to the best possible extent and high aerobic stabilities should be primary objectives when ensiling biogas feedstocks.

AI snapshot

Written from the paper’s full text.

TL;DR

In lab-scale maize silage, aerobic deterioration during 7 days of air exposure caused up to 20% organic dry matter loss and reduced methane yields, with 17% of the methane potential lost in the abstract. Silage additives, especially chemical and heterofermentative LAB treatments, improved aerobic stability and preserved or increased methane yields after air exposure, while having little effect under purely anaerobic storage.

Key findings

  • Aerobic deterioration reduced methane potential: 17% of methane potential was lost during 7 days air exposure; total ODM losses reached up to 20%. Methane yields after exposure ranged from 319–376 L N kg⁻¹ ODM added and 266–351 L N kg⁻¹ ODM orig; control and homofermentative LAB silages decreased by 3–12% based on ODM added and 5–19% based on ODM orig. Per 1 °C increase above ambient per day, methane yield loss was 1.1 L N kg⁻¹ ODM orig.
  • Aerobic stability of the control silage was 48 h after 49 days anaerobic storage and 154 h after 90 days; air stress during storage reduced it to 26 h. Chemical additive and heterofermentative or mixed LAB treatments increased stability beyond 182 h without air stress; under air stress, only LAB-he B and LAB-ho+he B completely avoided aerobic deterioration during 7 days exposure.
  • Under anaerobic storage, methane yields were 342–354 L N kg⁻¹ ODM added before ensiling, 344–381 L N kg⁻¹ ODM added after ensiling, and 326–356 L N kg⁻¹ ODM orig; additives had little effect. Prolonged 90-day storage increased methane yields by on average 3.5% (P = 0.0002). Air stress decreased the control methane yield by 4.5%, while additives prevented losses, with 3% higher yield for chemical additive and 4–9% higher for heterofermentative or mixed LAB when storage losses were considered.
  • After exposure to air, additive treatment led to up to 29% higher methane yields compared with the control after air-stress storage and subsequent air exposure, considering ODM losses; after 49 days anaerobic storage plus air exposure, mixtures of homo- and heterofermentative LAB gave up to 20% higher methane yields.

Methods

  • Maize variety PR39R68 was chopped to 6 mm and ensiled in 1.5 L glass jars with six commercial additives plus an untreated control. Storage was anaerobic for 49 or 90 days or under air stress for 49 days, with stoppers removed at day 28 and 42 for 24 h; all treatments were in triplicate at 25 °C.
  • Aerobic stability was tested by loosely filling silages into 1 L jars, incubating at 20 °C for 7 days, and recording temperature every 2 h; stability was the time until temperature rose more than 3 °C above ambient.
  • Batch anaerobic digestion followed VDI 4630 in 2 L reactors with 1.5 L inoculum and 50 g sample at 35 °C for 30 days; methane yields were calculated based on ODM added and ODM orig. Chemical analyses included DM, ODM, fibre fractions, pH, NH₃-N, organic acids, and alcohols; ANOVA used SAS 9.4 with SIMULATE and α = 0.05.

Limitations

  • Stated in the paper: the study is at laboratory scale, and effects of air stress and additives on methane yields “likely depend on the degree of air that penetrates into the silo in large scale application.” The paper also notes that oven-drying can cause losses of volatile organic acids and alcohols and that storage losses must be accounted for when evaluating silages.
  • Evident from the text: the experiment used a single maize variety from one site and harvest, lab-scale jars, and only a 7-day air-exposure period, with no farm-scale or long-term validation reported.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1016/j.biortech.2015.08.114

Cites

22 of 22 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 61 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    For heterofermentative LAB treatments, the 90 day storage duration resulted in a rise in acetic acid content compared to the silages stored for 49 days.

    “For heterofermentative LAB treatments, the 90 day storage duration resulted in a rise in acetic acid content compared to the silages stored for 49 days.”
    Quote in the paperNot a substantial claim
  • Findingown data

    Treatment with silage additives significantly influenced the DM and ODM content, and fibre fractions of the silages.

    “Treatment with silage additives significantly influenced the DM (P < 0.001) and ODM content (P < 0.05), and fibre fractions (P < 0.001) of the silages (Table 3).”
    Quote in the paperNot a substantial claim
  • Findingown data

    Silage additives significantly affected ODM losses during storage.

    “Silage additives also significantly affected ODM losses during storage (P < 0.001, Table 2).”
    Quote in the paperSubstantial claim
  • Findingown data

    Additive treatment had little effect on methane yield after anaerobic storage.

    “Additive treatment had little effects on methane yield after anaerobic storage.”
    • Also stated in: § 3.2.3. Methane yields of maize silages · plain
      “Treatments with silage additives showed little effects on methane yields of maize silages when stored for 49 and 90 days under anaerobic conditions (Fig. 1).”
    Quote in the paperSubstantial claim
  • Findingown data

    No considerable differences were found in chemical composition of freshly harvested maize before and after addition of silage additives.

    “No considerable differences were found in chemical composition of freshly harvested maize before and after addition of silage additives (Table 1).”
    Quote in the paperNot a substantial claim
  • May combine two claims. 50
  • Classified as probably not a substantial claim. 24
  • The quote only partly states this claim. 1

  • May combine two claims.

    Findingown data

    Only minor changes in chemical composition were determined which support the finding that silages were well preserved.

    “Further, only minor changes in chemical composition were determined (Table 3) which support the finding that silages where well preserved.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingnone given

    Without additive the ensilage process was dominated by lactic acid fermentation which could not be apparently improved by addition of homofermentative LAB.

    “Without additive the ensilage process was dominated by lactic acid fermentation which could not be apparently improved by addition of homofermentative LAB.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Highest DM and lowest fibre contents were found for silages with chemical additive, the treatment which resulted in lowest DM losses.

    “Highest DM and lowest fibre contents were found for silages with chemical additive, the treatment which resulted in lowest DM losses.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Air stress during storage reduced aerobic stability and increased methane losses.

    “Air stress during storage reduced aerobic stability and increased methane losses.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Lowest ODM losses occurred in silages with chemical additive, while highest losses occurred in silages with heterofermentative LAB.

    “Lowest losses occurred in silages with chemical additive, while highest losses occurred in silages with heterofermentative LAB.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingcitation

    Inoculation with heterofermentative LAB in the present study resulted in higher acetic acid content, higher pH-value, higher ethanol and NH3-N content and lower lactic acid content.

    “Inoculation with heterofermentative LAB in the present study resulted in higher acetic acid content, higher pH-value, higher ethanol and NH 3 -N content and lower lactic acid content which is in accordance with findings in literature (Driehuis et al., 1999).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Driehuis et al., 1999 source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    The NH3-N concentration of the maize silages was mainly affected by silage additive and storage duration with an increase in NH3-N concentration at prolonged storage and with addition of L. buchneri containing additives.

    “The NH 3 -N concentration of the maize silages was mainly affected by silage additive and storage duration with an increase in NH 3 -N concentration at prolonged storage and with addition of L. buchneri containing additives.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingcitation

    Raw material was characterised by high ODM content, and low fat and fibre content as typically found for maize whole crop biomass.

    “Raw material was characterised by high ODM content, and low fat and fibre content as typically found for maize whole crop biomass (Schittenhelm, 2008).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Schittenhelm, 2008 source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    No butyric acid or only traces of butyric acid were found.

    “No butyric acid or only traces of butyric acid were found”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The effects of storage duration and air stress during storage on chemical characteristics of maize silages were low and were not found to be significant.

    “The effects of storage duration and air stress during storage on chemical characteristics of maize silages were low and were not found to be significant (Table 3).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Propanol dominated in control and chemical additive silages, while ethanol dominated in silages with heterofermentative LAB treatment.

    “though propanol dominated in these silages and ethanol dominated in silages with heterofermentative LAB treatment.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Prolonged storage duration of 90 days predominantly increased the sum of fermentation products and slightly increased ODM losses by on average 0.5% (abs.).

    “Prolonged storage duration of 90 days predominantly increased the sum of fermentation products and slightly increased ODM losses by on average 0.5% (abs.).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Treatment with additives led to contrasting pattern of fermentation products of silages with significant effects on pH-value, lactic acid, acetic acid and alcohol content.

    “Treatment with additives led to contrasting pattern of fermentation products of silages with significant effects on pH-value (P < 0.001), lactic acid (P < 0.001), acetic acid (P < 0.001) and alcohol content (P < 0.001).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In aerobically stable silages, only minor changes occurred including 0.7-1.4% increase in ODM losses, slight increase in pH, and slight reduction of lactic acid.

    “In contrast, only minor changes occurred in aerobically stable silages including a 0.7-1.4% increase in ODM losses, a slight increase in pH values and a slight reduction of the lactic acid content.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In maize silages with aerobic stabilities below 60 h, lactic and acetic acid were almost completely degraded and alcohol concentration decreased.

    “In maize silages with aerobic stabilities below 60 h (control silages and silage with homofermentative LAB), lactic and acetic acid were almost completely degraded and the concentration of alcohols decreased.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    A slightly negative effect of LAB-ho on stability of maize silage during exposure to air was found in this study although homofermentative LAB failed to markedly change pattern of fermentation products.

    “A slightly negative effect of LAB-ho on the stability of maize silage during exposure to air was found in this study although homofermentative LAB failed to markedly change the pattern of fermentation products.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Storage for 49 days under air stress conditions decreased the methane yield of the control silage by 4.5%, while no negative effects were found for silages treated with silage additives.

    “Storage for 49 days under air stress conditions decreased the methane yield of the control silage by 4.5%, while no negative effects were found for silages treated with silage additives.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The heterofermentative LAB treatments resulted in slightly lower methane yields after 49 days of storage, and in 2-4% higher methane yields after 90 days of storage.

    “The heterofermentative LAB treatments resulted in slightly lower methane yields after 49 days of storage, and in 2-4% higher methane yields after 90 days of storage.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingcitation

    Aerobic stability of untreated maize silage can vary largely and values in present study lie within range reported by others.

    “Aerobic stability of the untreated maize silage can vary largely and values obtained in the present study lie within the range reported by others (e.g.Driehuis et al., 1999;Ranjit and Kung, 2000;Wilkinson and Davies, 2013).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Driehuis et al., 1999 source

      Not checked in the free run.

    • cites Ranjit and Kung, 2000 source

      Not checked in the free run.

    • cites Wilkinson and Davies, 2013

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    Storage conditions during ensilage affect methane yields of maize silages, as opposed to silage additive treatments under anaerobic storage.

    “As opposed to silage additive treatments under anaerobic storage, storage conditions during ensilage were found to affect methane yields of maize silages.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    A 2-3% lower methane yield was observed with chemical additive, and a 1-3% higher methane yield was measured with additives containing homo-and heterofermentative LAB compared with the control silages.

    “A 2-3% lower methane yield was observed with chemical additive, and a 1-3% higher methane yield was measured with additives containing homo-and heterofermentative LAB compared with the control silages.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    A 3% higher methane yield was found for silages treated with chemical additive, and 4-9% higher methane yields were found for silages treated with heterofermentative or homo-and heterofermentative LAB when taking account of storage losses.

    “Thus, a 3% higher methane yield was found for silages treated with chemical additive, and 4-9% higher methane yields were found for silages treated with heterofermentative or homo-and heterofermentative LAB when taking account of storage losses.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Effects of air stress and use of silage additives under air stress conditions on methane yields were comparatively low despite significant differences.

    “Although significant differences in methane yields were found in the present study, effects of air stress and the use of silage additives under air stress conditions on methane yields were still comparatively low.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Methane yields of maize ranged from 342-354 L N kg−1 ODM added prior to ensilage, and from 344-381 L N kg−1 ODM added after ensiling.

    “Methane yields of maize ranged from 342-354 L N kg À1 -ODM added prior to ensilage, and from 344-381 L N kg À1 ODM added after ensiling.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Methane yields of maize silages after 7 days exposure to air varied between 319 and 376 L N kg−1 ODM added, and between 266 and 351 L N kg−1 ODM orig when considering total storage losses.

    “Methane yields of maize silages after 7 days exposure to air varied largely between 319 and 376 L N kg À1 ODM added , and between 266 and 351 L N kg À1 ODM orig when considering total storage losses (Fig. 2).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Largest effects were observed for silages with lowest aerobic stability, i.e., silages without additive and with homofermentative LAB, and for silages stored under air stress conditions.

    “Largest effects were observed for silages with lowest aerobic stability, hence, for silages without additive and with addition of homofermentative LAB, and for silages stored under air stress conditions.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    After 90 days anaerobic storage, control silage was aerobically more stable and exposure to air significantly decreased methane yield only for maize silage treated with homofermentative LAB (LAB-ho).

    “After 90 days of anaerobic storage the control silage was aerobically more stable and exposure to air significantly decreased the methane yield only for the maize silage treated with homofermentative LAB (LAB-ho).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Penetration of oxygen into the silo involves an increase in temperature above ambient and elevated mass and nutrient losses.

    “This involves an increase in temperature above ambient and elevated mass and nutrient losses (Wilkinson and Davies, 2013).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Wilkinson and Davies, 2013

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    An increased concentration of acetic acid in silages after inoculation with heterofermentative LAB is desired since it can inhibit yeasts and moulds and increase the aerobic stability.

    “An increased concentration of acetic acid in silages after inoculation with heterofermentative LAB is desired since it can inhibit yeasts and moulds and increase the aerobic stability (Danner et al., 2003).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Danner et al., 2003 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Homofermentative LAB ferment sugars almost exclusively to lactic acid while heterofermentative LAB are known to ferment sugars to lactic acid, acetic acid, alcohols and carbon dioxide.

    “Homofermentative LAB ferment sugars almost exclusively to lactic acid while heterofermentative LAB are known to ferment sugars to lactic acid, acetic acid, alcohols and carbon dioxide (McDonald et al., 1991).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites McDonald et al., 1991

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    DM content within the optimal range for ensiling and a low buffering capacity suggest good conditions for lactic acid fermentation.

    “DM content within the optimal range for ensiling and a low buffering capacity suggest good conditions for lactic acid fermentation (McDonald et al., 1991).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites McDonald et al., 1991

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Additives containing a combination of homo-and heterofermentative LAB can be advantageous over the sole addition of heterofermentative LAB since they promote a more rapid initial lactic acid formation and pH reduction, and can decrease fermentation losses.

    “Additives containing a combination of homo-and heterofermentative LAB can be advantageous over the sole addition of heterofermentative LAB since they promote a more rapid initial lactic acid formation and pH reduction, and can decrease fermentation losses (Filya, 2003).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Filya, 2003 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Maize is a crop with exceptional good ensiling characteristics due to its relatively high DM content at harvest, its low buffering capacity and adequate level of water-soluble carbohydrates (WSC).

    “Maize is a crop with exceptional good ensiling characteristics due to its relatively high DM content at harvest, its low buffering capacity and adequate level of water-soluble carbohydrates (WSC) (McDonald et al., 1991).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites McDonald et al., 1991

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductcitation

    DM content and all analytical parameters expressed on DM basis were corrected for losses of volatile organic compounds during oven drying.

    “DM content and all analytical parameters expressed on DM basis were corrected for losses of volatile organic compounds during oven drying as suggested by Weißbach and Strubelt (2008).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Weißbach and Strubelt (2008)

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    McEniry et al. (2014) analysed the methane yield of grass silage before and after exposure to air, however, silages were comparatively stable and no significant change in methane yield due to exposure to air was found.

    “McEniry et al. (2014) analysed the methane yield of grass silage before and after exposure to air, however, silages were comparatively stable and no significant change in methane yield due to exposure to air was found.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites McEniry et al., 2014 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationnone given

    Air stress conditions during storage likely slowed lactic acid production, and stimulated acetic acid production in silages with addition of L. buchneri which resulted in numerically increased mass losses.

    “Air stress conditions during storage likely slowed lactic acid production, and stimulated acetic acid production in silages with addition of L. buchneri which resulted in numerically increased mass losses.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Methane content was corrected for its dilution within the headspace of the experimental set-up.

    “Methane content was corrected for its dilution within the headspace of the experimental set-up (VDI, 2006).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites VDI, 2006

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Changes that occur during the feed-out phase are as important for preservation of nutrients as the silage fermentation process itself.

    “As emphasized by Wilkinson and Davies (2013), changes that occur during the feed-out phase are as important for preservation of nutrients as the silage fermentation process itself.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Wilkinson and Davies, 2013

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    L. buchneri is reported to increasingly convert lactic acid into acetic acid at decreasing pH of silages.

    “L. buchneri is reported to increasingly convert lactic acid into acetic acid at decreasing pH of silages (Oude Elferink et al., 2001).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Oude Elferink et al., 2001 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    After addition of heterofermentative LAB Driehuis et al. (1999) observed a shift of lactic acid towards acetic acid and alcohols with longer storage duration which supports results of the present study.

    “After addition of heterofermentative LAB Driehuis et al. (1999) observed a shift of lactic acid towards acetic acid and alcohols with longer storage duration which supports results of the present study.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Driehuis et al., 1999 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Batch anaerobic digestion tests were conducted in accordance with VDI 4630.

    “Effects of additive and storage treatments on methane production of maize were analysed in batch anaerobic digestion tests in accordance with VDI 4630 (VDI, 2006).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites VDI, 2006

      Not checked in the free run.

  • May combine two claims.

    Premisenone given

    While a number of studies on the effects of silage fermentation on methane yields exist already, studies on effects of aerobic deterioration on methane production are scarce.

    “While a number of studies on the effects of silage fermentation on methane yields exist already, studies on effects of aerobic deterioration on methane production are scarce.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Among biogas crops, maize is the most widely used crop species for methane production in farm-scale biogas plants.

    “Among biogas crops, maize is the most widely used crop species for methane production in farm-scale biogas plants (Murphy et al., 2011).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Murphy et al., 2011

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Air might infiltrate into the silage through inappropriate or damaged protecting cover, or by diffusion through the cover during the storage phase.

    “Firstly, air might infiltrate into the silage through inappropriate or damaged protecting cover, or by diffusion through the cover during the storage phase (Driehuis et al., 1999).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Driehuis et al., 1999 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The NH3-N concentration in silages indicates the level of protein degradation.

    “The NH 3 -N concentration in silages indicates the level of protein degradation (McDonald et al., 1991).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites McDonald et al., 1991

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Increased NH3-N concentrations after inoculation with L. buchneri have been reported before and might be explained by an increase in pH during storage due to high metabolic activity of L. buchneri.

    “Increased NH 3 -N concentrations after inoculation with L. buchneri have been reported before and might be explained by an increase in pH during storage due to high metabolic activity of L. buchneri (Filya, 2003).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Filya, 2003 source

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductnone given

    Measured biogas volume was corrected for the volume produced by the blank (inoculum without sample) and was normalised to standard conditions.

    “Measured biogas volume was corrected for the volume produced by the blank (inoculum without sample) and was normalised to standard conditions (dry gas, 0 °C, 1013 hPa).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductnone given

    All treatments were conducted in triplicate.

    “All treatments were conducted in triplicate.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Treatments with homofermentative LAB resulted in decreasing methane yields of up to 21% to increasing methane yields up to 3%.

    “Treatments with homofermentative LAB resulted in decreasing methane yields of up to 21% to increasing methane yields up to 3% (Neureiter et al., 2005;Plöchl et al., 2009)”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Neureiter et al., 2005

      Not checked in the free run.

    • cites Plöchl et al., 2009

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    An increase in acetic acid content can occur during initial stage of aerobic deterioration, but acetic acid is degraded with proceeding aerobic deterioration.

    “An increase in acetic acid content can occur during the initial stage of aerobic deterioration, but acetic acid is degraded with proceeding aerobic deterioration (Honig, 1975).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Honig, 1975

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Undissociated acetic acid and other short-chain fatty acids inhibit growth of yeasts and moulds while lactic acid is largely ineffective against these initiators of aerobic deterioration.

    “Undissociated acetic acid, as well as other short-chain fatty acids, are also known to inhibit the growth of yeasts and moulds while lactic acid is largely ineffective against these initiators of the aerobic deterioration process (Danner et al., 2003;Wilkinson and Davies, 2013).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Danner et al., 2003 source

      Not checked in the free run.

    • cites Wilkinson and Davies, 2013

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S4 (based).

    Premisenone given

    Methane yields are usually reported based on ODM with the DM content being determined by oven-drying.

    “Methane yields are usually reported based on ODM with the DM content being determined by oven-drying.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    An enhancing effect of silage fermentation on methane yields based on ODM added to the anaerobic digestion process as compared with methane yields of biomass prior to ensiling is in accordance with findings in literature.

    “An enhancing effect of silage fermentation on methane yields based on ODM added to the anaerobic digestion process as compared with methane yields of biomass prior to ensiling is in accordance with findings in literature (e.g.Gao et al., 2012;Herrmann et al., 2014;Kafle and Kim, 2013) and was discussed in detail previously (Herrmann et al., 2011).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Gao et al., 2012 source

      Not checked in the free run.

    • cites Herrmann et al., 2014 source

      Not checked in the free run.

    • cites Kafle and Kim, 2013

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Fibre fractions are reported to be negatively correlated to the methane yield.

    “Fibre fractions are reported to be negatively correlated to the methane yield (Herrmann et al., 2014;Rath et al., 2013)”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Herrmann et al., 2014 source

      Not checked in the free run.

    • cites Rath et al., 2013 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    A rapid reduction in lactic acid, alcohol and WSC content, an increase in pH-value and rapidly increasing DM losses are typically found in aerobically deteriorating silages.

    “A rapid reduction in lactic acid, alcohol and WSC content, an increase in pH-value and rapidly increasing DM losses are typically found in aerobically deteriorating silages (Honig, 1975;Ranjit and Kung, 2000).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Honig, 1975

      Not checked in the free run.

    • cites Ranjit and Kung, 2000 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Salts of propionic and benzoic acid, active ingredients of the chemical additive, feature antimycotic properties and have been successfully used to reduce growth of yeasts and moulds.

    “Salts of propionic and benzoic acid, which are active ingredients of the chemical additive, feature antimycotic properties and have been successfully used to reduce growth of yeasts and moulds (Kung et al., 2003).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Kung et al., 2003

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    WSC are the main compounds converted into organic acids during ensiling.

    “WSC are the main compounds converted into organic acids during ensiling (McDonald et al., 1991).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites McDonald et al., 1991

      Not checked in the free run.

  • May combine two claims. The quote only partly states this claim.

    Interpretationreasoning

    Air stress during storage reduces aerobic stability and increases risk of aerobic spoilage, likely by promoting yeasts.

    “Air stress during the storage period likely promoted the growth or survival of yeasts and resulted in a more rapid multiplication of yeasts when aerobic conditions were available at feed-out.”
    • Also stated in: § 4. Conclusions · plain
      “Air stress during storage reduces the aerobic stability at feed-out and dramatically increases the risk of aerobic spoilage.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Treatments with combinations of homo-and heterofermentative LAB were reported to affect the methane yield of maize silage within a range of −13% to +22%.

    “and treatments with combinations of homo-and heterofermentative LAB were reported to affect the methane yield of maize silage within a range of À13% to +22% (Neureiter et al., 2005;Vervaeren et al., 2010).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Neureiter et al., 2005

      Not checked in the free run.

    • cites Vervaeren et al., 2010 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    The decrease in methane yield due to air stress might be due to initiation of aerobic microbial processes.

    “This might be due to initiation of aerobic microbial processes, although the observed effects on the products of silage fermentation were low (Section 3.2.1).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    Exclusion of air during storage is essential to prevent aerobic deterioration and preserve methane potential of silage.

    “Results of the present study further show that exclusion of air during storage is essential in order to prevent aerobic deterioration during feed-out.”
    • Also stated in: § 4. Conclusions · boosted
      “Exclusion of air is a fundamental requirement for successful preservation of the methane potential of silage feedstock for biogas production.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Aerobic deterioration associated with degradation of organic acids and WSC resulted in decrease in DM and ODM content and increasing portions of less easily degradable components such as crude protein and fibre fractions.

    “Aerobic deterioration associated with the degradation of organic acids and WSC resulted in a decrease in DM and ODM content, and in increasing portions of components that are less easily degradable such as crude protein and fibre fractions.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    A marked increase in acetic acid during exposure to air in silages inoculated with L. buchneri strains has been reported previously and can be attributed to continuing acetic acid production by L. buchneri under aerobic storage conditions.

    “A markedly increase in acetic acid during exposure to air in silages inoculated with L. buchneri strains have been reported previously and can be attributed to a continuing acetic acid production by L. buchneri under aerobic storage conditions (Ranjit and Kung, 2000).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Ranjit and Kung, 2000 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Suboptimal conditions that allow air to enter silage during storage, such as low compaction and inappropriate or damaged sealing, decrease aerobic stability and substantially increase risk for high losses in methane production.

    “Suboptimal conditions that allow air to enter the silage during storage, such as low compaction and inappropriate or damaged sealing, decrease aerobic stability and substantially increase the risk for high losses in methane production.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    Changes in chemical composition due to aerobic deterioration, mainly loss in organic acids, alcohols and WSC, decrease the amount of available substrates for anaerobic digestion and thus decrease methane yield.

    “It can be assumed that the changes in chemical composition due to aerobic deterioration, mainly the loss in organic acids, alcohols and WSC decrease the amount of available substrates for anaerobic digestion, and thus decrease the methane yield.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    Aerobic deterioration decreases methane yield and causes high biomass/ODM losses.

    “Aerobic deterioration resulted in a decrease in methane yield and in high ODM losses.”
    • Also stated in: § 3.3.3. Methane yields of maize silages after exposure to air · hedged
      “Results indicate that aerobic deterioration has a largely negative effect on methane yield and leads to high losses in methane production potential within a short period of time.”
    • Also stated in: § 4. Conclusions · plain
      “Aerobic deterioration causes high biomass losses and additionally decreases the methane yield.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    Under suboptimal conditions, silage additives effective to increase aerobic stability can postpone aerobic deterioration and prevent methane losses.

    “If a considerable risk for aerobic deterioration exists, silage additives effective to increase the aerobic stability can postpone aerobic deterioration and aid in preventing high methane losses.”
    • Also stated in: § 4. Conclusions · plain
      “Under suboptimal conditions chemical additives and heterofermentative LAB effective to enhance the aerobic stability can prevent losses and assist in preserving energy-rich biogas feedstocks.”
    Quote in the paperSubstantial claim
67 of 67

  • The paper relies on this without support.

    Acetic acid can increase aerobic stability and can directly be converted into methane during anaerobic digestion.

    “Acetic acid can increase aerobic stability and can directly be converted into methane during the anaerobic digestion process.”

  • The paper relies on this without support.

    The lab-scale air stress conditions and storage periods are representative of farm-scale silage storage conditions.

    “It is likely that these effects will depend on the degree of air that penetrates into the silo in large scale application.”
2 of 2

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Inoculants containing selected strains of L. buchneri and L. diolivorans can shift silage biochemistry towards limiting lactic acid synthesis and increasing acetic and propionic acid synthesis, thereby ensuring overall stability, aerobic stability and increased biogas yield.

    “Under the influence of inoculants containing selected bacterial strains from L. buchneri and L. diolivorans species, biochemical changes may be aimed at limiting the synthesis of lactic acid, while increasing the synthesis of acetic and propionic acids, and thus, ensuring overall stability, aerobic stability and increased biogas yield from these silages (Herrmann et al. 2015; Nussbaum 2012).”

    From Trends in designing microbial silage quality by biotechnological methods using lactic acid bacteria inoculants: a minireview. (2019) · cites this paper as Herrmann et al. 2015

Cites

Flagged first, then by citations

Research works printed but not linked: 7

  1. Honig, 1975, Umsetzungen und Verluste bei der Nachgärung, Das wirtschaftseigene Futter, 21, 25
  2. Multerer, 2014, The impact of biogas raw materials on the utilized agricultural area – an assessment of alternative raw material, Anliegen Nat., 36, 54
  3. Neureiter, M., dos Santos, J.T.P., Lopez, C.P., Pichler, H., Kirchmayr, R., Braun, R., 2005. Effect of silage preparation on methane yields from whole crop maize silages. In: Proceedings of the 4th International Symposium on Anaerobic Digestion of Solid Waste, Copenhagen, Denmark, pp. 109–115.
  4. Nussbaum, H., 2012. Effects of silage additives based on homo- or heterofermentative lactic acid bacteria on methane yields in the biogas processing. In: Proceedings of the XVI International Silage Conference, 2–4 July 2012, Hämeenlinna, Finland. MTT Agrifood Research Finland, University of Helsinki, pp. 452–453.
  5. Plöchl, 2009, Influence of silage additives on methane yield and economic performance of selected feedstock, Agric. Eng. Int.: CIGR J, XI, 1
  6. VDI, 2006. VDI standard procedures 4630: fermentation of organic materials. In: Verein Deutscher Ingenieure (Eds.), Characterisation of the substrate, sampling, collection of material data, fermentation tests. Beuth Verlag, Berlin, pp. 92.
  7. Weißbach, 2008, Correcting the dry matter content of maize silages as a substrate for biogas production, Landtechnik, 63, 82

Cited by

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Related

Authors
Herrmann, C., Idler, C., & Heiermann, M.
Affiliations
Leibniz Institute for Agricultural Engineering and Bioeconomy (DE)
Corresponding author
Herrmann, Christiane
ORCID
Venue
Bioresource Technology
Publisher
Elsevier BV
Published
2015-12
Volume
197
Pages
393-403
ISSN
0960-8524 (ISSN-L)
DOI
10.1016/j.biortech.2015.08.114
OpenAlex
W1231782417
Semantic Scholar
96ad542e76d7f9f38f59c6f7cbfb9f6622de897b
Cited by
90
References
22
Citations by year
2026: 4 · 2025: 5 · 2024: 7 · 2023: 10 · 2022: 10 · 2021: 12 · 2020: 10 · 2019: 11 · 2018: 12 · 2017: 3 · 2016: 6
FWCI
9.53
Type
journal article
Language
en
Open access
Licence
Locations
  • Bioresource Technology (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • RENATE (submittedVersion, cc-by-nc-nd)
  • RENATE (cc-by)
Funders
Federal Ministry of Food and Agriculture
Topics
  • Physical Sciences › Engineering › Building and Construction › Anaerobic Digestion and Biogas Production
  • Life Sciences › Agricultural and Biological Sciences › Agronomy and Crop Science › Ruminant Nutrition and Digestive Physiology
  • Physical Sciences › Engineering › Biomedical Engineering › Biofuel production and bioconversion
Keywords
corn silage, aerobic stability, silage additives, biogas production, methane yield, air exposure, silage storage, heterofermentative lactic acid bacteria, silage inoculants
MeSH terms
Air, Benzoates, Biotechnology, Zea mays, Fermentation, Methane, Propionates, Silage, Biofuels

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

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