The DOI matches its Crossref record; 17 of the 17 references it cites were found in a registry or an index; none of the 17 sources its claims cite is checked for support yet.
Effects of lipids and oleic acid on biomass development in anaerobic fixed-bed reactors. Part II: Oleic acid toxicity and biodegradability
Open accessAbstract
Oleic acid toxicity and biodegradability were followed during long-term operation of two similar anaerobic fixed-bed units. When treating an oleate based effluent, the sludge from the bioreactor that was acclimated with lipids during the first operation period, showed a higher tolerance to oleic acid toxicity (IC50 = 137 mg/l) compared with the sludge fed with a non-fat substrate (IC50 = 80 mg/l). This sludge showed also the highest biodegradation capacity of oleic acid, achieving maximum methane production rates between 33 and 46 mlCH4(STP)/gVS.day and maximum percentages of methanization between 85 and 98% for the range of concentrations between 500 and 900 mg oleate/l. When oleate was the sole carbon source fed to both digesters, the biomass became encapsulated with organic matter, possibly oleate or an intermediate of its degradation, e.g. stearate that was degraded at a maximum rate of 99 mlCH4(STP)/gVS.day. This suggests the possibility of using adsorption-degradation cycles for the treatment of LCFA based effluents. Both tolerance to toxicity and biodegradability of oleic acid were improved by acclimatization with lipids or oleate below a threshold concentration.
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Written from the paper’s full text.
TL;DR
Long-term operation of two anaerobic fixed-bed units showed that sludge pre-exposed to lipids developed greater tolerance to oleic acid toxicity and higher oleate biodegradation capacity than sludge fed a non-fat substrate. When oleate became the sole carbon source, biomass became encapsulated with adsorbed organic matter, suggesting possible adsorption–degradation cycles for lipid-rich effluents.
Key findings
- Sludge acclimated with lipids had higher tolerance to oleic acid toxicity (IC50 = 137 mg/l) than sludge fed a non-fat substrate (IC50 = 80 mg/l); across the work, IC50 values ranged from 30 to 295 mg/l.
- The lipid-acclimated sludge achieved maximum methane production rates between 33 and 46 mlCH4(STP)/gVS.day and maximum methanization percentages between 85 and 98% for oleate concentrations of 500–900 mg/l.
- When oleate was the sole carbon source, biomass became encapsulated with organic matter, possibly oleate or an intermediate such as stearate, which was degraded at a maximum rate of 99 mlCH4(STP)/gVS.day.
- Blank-vial background methane production from adsorbed matter reached 99 and 84 mlCH4(STP)/gVS.day for reactors RI and RII, respectively—two-fold higher than the maximum oleate degradation rate measured in biodegradability tests.
Methods
- Two similar anaerobic fixed-bed units were operated long-term: start-up on skim milk; Period I had RI shifted to whole milk while RII continued skim milk for 246 days; Period II fed increasing oleate with skim milk as co-substrate; Period III fed oleate as the sole carbon source.
- Toxicity and biodegradability batch tests used a pressure transducer technique under strict anaerobic conditions, with basal medium at pH 7.0–7.2 and no added calcium or trace nutrients.
- Toxicity tests added 30 mM acetate plus oleate at 100, 300, 500, 700, and 900 mg/l in triplicate; biodegradability tests added the same oleate concentrations in duplicate and measured maximum methane production rate, percentage of methanization, and lag phases, with specific values divided by vial VS content.
Limitations
- The paper states that the hypothesis that oleate was reduced to stearate prior to adsorption needs experimental validation.
- Evident from the text: toxicity and biodegradability were assessed in batch assays with suspended sludge at 37°C without added calcium or magnesium, so results may not directly translate to continuous high-rate digesters and are sensitive to temperature, cations, and sludge characteristics.
- Evident from the text: at the end of operation, extremely high background methane production from adsorbed organic matter complicated interpretation, although background methane was discounted in reported MMPR and PM values.
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24 Own result · 9 No full text of the sources · 9 Own interpretation · 6 No basis given · 5 Own method · 2 Not checked yet · 1 Sources not found
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The methane production rate from this adsorbed matter (99 and 84 mlCH 4(STP) /gVS.day, for RI and RII, respectively) was two-fold higher than the maximum oleate degradation rate measured in the biodegradability tests.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > CONCLUSIONS
plaincorrelational- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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- The authors state this as an assumption: The adsorbed organic matter responsible for background methane production is oleate or an intermediate of its degradation.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“the sludge from the bioreactor that was acclimated with lipids during the ®rst operation period, showed a higher tolerance to oleic acid toxicity (IC 50 =137 mg/l) compared with the sludge fed with a non-fat substrate (IC 50 =80 mg/l).”
- Also stated in: § CONCLUSIONS · plain
“When treating an oleate based euent, the sludge that had been pre-exposed to lipids showed higher tolerance to oleic acid toxicity than the sludge that had been fed with a non-fat substrate.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Abstract
plaincorrelational- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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- Rests on an assumption: The two anaerobic fixed-bed units (RI and RII) were similar enough that differences in sludge behavior can be attributed to substrate composition (lipids vs non-fat).
- Also stated in: § CONCLUSIONS · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“When oleate was the sole carbon source fed to both digesters, the biomass became encapsulated with organic matter, possibly oleate or an intermediate of its degradation, e.g.stearate that was degraded at a maximum rate of 99 mlCH 4(STP) /gVS.day.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Abstract
plaindirect- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
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- The authors state this as an assumption: The adsorbed organic matter responsible for background methane production is oleate or an intermediate of its degradation.
In the paper
“which con®rms the higher susceptibility of acetoclastic bacteria to oleic acid, relative to hydrogenophilic bacteria, as reported by Hanaki et al. (1981).”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Toxicity of sodium oleate towards acetoclastic bacteria
What the sources say
- Not checked — no full text of the sourcecites Hanaki et al., 1981 source
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In the paper
“It was also observed that the highest background methane production rate was obtained for the highest concentration of background substrate.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Methane production due to background substrate
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The low methane production rates obtained in the biodegradability batch experiments for the sludges samples from RI at the end of the operation resulted, in part, from the extremely high residual methane production due to background substrate.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Methane production due to background substrate
plaindirect- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The obtained values for IC 50 in the present work ranged from 30 to 295 mg/l and were obtained for suspended sludge at 378C without added calcium or magnesium.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Toxicity of sodium oleate towards acetoclastic bacteria
plain- Asserted: passes — The authors put it forward as true.
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- Rests on an assumption: The batch toxicity and biodegradability assays reflect the behavior of the sludge in the continuous fixed-bed reactors.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Furthermore, the obtained values are signi®cantly higher (two-fold) than the maximum values obtained from the oleate biodegradability tests (Table 2).”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Methane production due to background substrate
plain- Asserted: passes — The authors put it forward as true.
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In the paper
“In fact, when performing the blank vials where no substrate was added, an extremely high background methane production was detected, when compared with the corresponding production obtained with the other sludges.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Methane production due to background substrate
plaincorrelational- Asserted: passes — The authors put it forward as true.
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In the paper
“When performing the biodegradability tests with the sludge collected at the end of the operation, a lag phase was observed prior to the initial methane production, for concentrations higher than 300 mg/l (Table 2, last line).”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Methane production due to background substrate
plaincorrelational- Asserted: passes — The authors put it forward as true.
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- It may state two separate claims as one. 22
- Probably not a substantial claim. 12
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The methane production rate from this adsorbed matter (99 and 84 mlCH 4(STP) /gVS.day, for RI and RII, respectively) was two-fold higher than the maximum oleate degradation rate measured in the biodegradability tests.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > CONCLUSIONS
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
- The authors state this as an assumption: The adsorbed organic matter responsible for background methane production is oleate or an intermediate of its degradation.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This sludge showed also the highest biodegradation capacity of oleic acid, achieving maximum methane production rates between 33 and 46 mlCH 4(STP) /gVS.day and maximum percentages of methanization between 85 and 98% for the range of concentrations between 500 and 900 mg oleate/l.”
- Also stated in: § CONCLUSIONS · plain
“The sludge that had been acclimatized with lipids showed an increasing biodegradation capacity of oleic acid along the trial period.Maximum methane production rates between 33 and 46 mlCH 4(STP) /gVS.day and maximum percentages of methanization between 85 and 98% were obtained for the range of concentrations between 500 and 900 mg/l.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Abstract
plaindirect- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
- Also stated in: § CONCLUSIONS · plain
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“However, when the feeding was changed to a blend of skim milk and sodium oleate (Period II) the sludge RII lost its resistance whereas sludge from RI achieved a maximum of tolerance to oleate during this period.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Toxicity of sodium oleate towards acetoclastic bacteria
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“This sludge exhibited the highest capacity of oleate biodegradation evidenced by the highest methane production rates, the highest percentages of methanization and the lowest lag phases.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Oleate biodegradability
plaincorrelationalSingle case- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Although no eect was evident in the speci®c acetoclastic activity which was enhanced for both sludges during this period (see Part I), it was clear that the precontact with lipids delayed the acetate degradation, when in the presence of sodium oleate.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Toxicity of sodium oleate towards acetoclastic bacteria
boosteddirect- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“During Period II, when oleate was fed with a co-substrate, no signi®cant background methane production was detected, and was reduced by comparison with the values of Period I (Table 3).”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Methane production due to background substrate
plain- Asserted: passes — The authors put it forward as true.
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The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“This behaviour was typical during Period I, but the dierences between the two sludges became more pronounced towards the end of this operation period.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Toxicity of sodium oleate towards acetoclastic bacteria
plaincorrelational- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The sludge collected at the end of the experiment, when oleate was the sole carbon source fed to the reactor, exhibited percentages of methanization higher than 80% for the concentrations of 700 and 900 mg/l, but methane production rates decreased signi®cantly and lag phases increased.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Oleate biodegradability
plaincorrelational- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The potential speci®c acetoclastic activity followed the same decreasing trend observed during Period II (see Part I), and the resistance to sodium oleate decreased for both sludges.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Toxicity of sodium oleate towards acetoclastic bacteria
plaincorrelational- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“During Period I, the tolerance to oleate increased for both sludges, but particularly for sludge RII.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Toxicity of sodium oleate towards acetoclastic bacteria
plaindirect- Asserted: passes — The authors put it forward as true.
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A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In general, it was shown that there was an increase in the methane production rate and in the percentage of methanization for all concentrations of oleate until Period II, when oleate was fed with a co-substrate.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Oleate biodegradability
plaindirect- Asserted: passes — The authors put it forward as true.
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In the paper
“However, acetate and oleate degradation by sludge from RII followed a diauxic behavior and no lag phase was observed over the range of concentrations under study.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Toxicity of sodium oleate towards acetoclastic bacteria
plain- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A result the paper reports from its own data — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The values obtained for IC 50 were 50 mg/l for acetoclastic bacteria and 200 mg/l for the hydrogenophilic bacteria, which con®rms the higher susceptibility of acetoclastic bacteria to oleic acid, relative to hydrogenophilic bacteria, as reported by Hanaki et al. (1981).”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Toxicity of sodium oleate towards acetoclastic bacteria
plain- Asserted: passes — The authors put it forward as true.
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A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“The long term contact with lipids, or oleate below a threshold concentration, induced adaptation to biodegradation of oleic acid.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > CONCLUSIONS
plaindirect- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
- Rests on an assumption: The threshold concentration of oleate below which adaptation occurs is a real and relevant phenomenon.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“Therefore, the addition of oleate above a threshold concentration aected the acetoclastic activity as well as the tolerance of these bacteria to oleate.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Toxicity of sodium oleate towards acetoclastic bacteria
plaindirect- Asserted: passes — The authors put it forward as true.
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A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“Adaptation of methanogenic bacteria to LCFA is discussed in the literature, but most of the previous works report on results from batch assays (Hanaki et al., 1981;Koster and Cramer, 1987;Angelidaki and Ahring, 1992) and the general conclusion is that no adaptation of methanogenic bacteria to LCFA occurs.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Toxicity of sodium oleate towards acetoclastic bacteria
What the sources say
plain- Asserted: passes — The authors put it forward as true.
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Probably not a substantial claim. It may state two separate claims as one.
In the paper
“According to the degradation pathways of oleic acid described by Weng and Jeris (1976), the ®rst step in oleate degradation is the reduction of oleate to stearate, which is a saturated LCFA, less toxic than oleic acid.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Methane production due to background substrate
What the sources say
- Not checked — no full text of the sourcecites Weng and Jeris, 1976 source
plaindirect- Asserted: passes — The authors put it forward as true.
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It may state two separate claims as one.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“This indicates that the degradation of the adsorbed organic matter was delayed by the added oleic acid, suggesting that this LCFA exerted a toxic eect on the degradation of the adsorbed matter.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Methane production due to background substrate
hedgedconditional- Asserted: passes — The authors put it forward as true.
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- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- The authors state this as an assumption: The adsorbed organic matter responsible for background methane production is oleate or an intermediate of its degradation.
A conclusion the paper draws from its own results — it cites no other source for it, so there is none to check. The quote shows it is in the paper.
In the paper
“In other words, it seems that the pre-contact with lipids aected the type of tolerance developed by the sludge, the pre-exposition to lipids seeming to be bene®cial to the development of resistance to oleic acid in the treatment of an euent containing this LCFA.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Toxicity of sodium oleate towards acetoclastic bacteria
hedgedconditional- Asserted: passes — The authors put it forward as true.
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- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
- Rests on an assumption: The two anaerobic fixed-bed units (RI and RII) were similar enough that differences in sludge behavior can be attributed to substrate composition (lipids vs non-fat).
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“The speci®c values of degradation rate and percentage of methanization were obtained by dividing the methane production rates by the VS content of each vial determined at the end of the experiment.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Sludge characterization
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
In the paper
“The existing literature suggests that LCFA exert a bactericidal eect on methanogenic bacteria and no adaptation was observed.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > INTRODUCTION
What the sources say
- Not checked — no full text of the sourcecites Rinzema et al., 1994 source
hedgeddirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may state two separate claims as one.
None of the sources cited for this claim have been checked yet.
In the paper
“The ®xed-bed reactors were specially designed to allow the biomass to be periodically withdrawn (Alves et al., 1998).”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > INTRODUCTION
What the sources say
- Not checked yetcites Alves et al., 1998 source
Checked before — its earlier verdict is held back until a new check runs.
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
- Not checked yet
In the paper
“Hanaki et al. (1981) concluded that oleate adsorbed to be biomass within 24 h.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Methane production due to background substrate
What the sources say
- Not checked — no full text of the sourcecites Hanaki et al., 1981 source
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Toxicity batch experiments were performed in triplicate assays.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Sludge characterization
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
The paper states this without a source or data behind it here, so there is nothing to check it against. The quote shows it is in the paper.
In the paper
“However, in none of these works was it proven that the adsorbed product was eectively oleic acid.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Methane production due to background substrate
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Strict anaerobic conditions were maintained.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Sludge characterization
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“Methanogenic toxicity and biodegradability tests were performed using a pressure transducer technique (Colleran et al., 1992;Colleran and Pistilli, 1994).”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Sludge characterization
What the sources say
- Not checked — no full text of the sourcecites Colleran et al., 1992 source
- Not checked — no full text of the sourcecites Colleran and Pistilli, 1994
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Background methane production due to residual substrate was discounted in the values of MMPR and PM.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Sludge characterization
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim.
A claim is checked only against the cited paper’s full text, never its abstract, and none is available for its sources.
In the paper
“Sodium oleate was used as a model for LCFA because it is, in general, the most abundant of all LCFA present in wastewater (Komatsu et al., 1991), has a good solubility, it is the most important LCFA produced by whole milk degradation (Hanaki et al., 1981) and is one of the more toxic LCFA (Galbraith et al., 1971).”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > INTRODUCTION
What the sources say
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
It may state two separate claims as one.
What the paper did — it cites no source for this, so there is none to check. The quote shows it is in the paper.
In the paper
“Biodegradability tests were performed in duplicate assays.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Sludge characterization
plain- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: fails — The paper’s conclusions may not depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. The paper’s conclusions may not depend on it.
In the paper
“Oleate adsorption was found to be highly concentration-dependent in batch experiments and induced the inhibition of methanogenic bacteria by increasing the lag-phases before initial methane production, whereas in UASB reactors sludge ¯otation was related to LCFA/sludge loading rates.”
§ EFFECTS OF LIPIDS AND OLEIC ACID ON BIOMASS DEVELOPMENT IN ANAEROBIC FIXED-BED REACTORS. PART II: OLEIC ACID TOXICITY AND BIODEGRADABILITY > Methane production due to background substrate
What the sources say
- Not checked — no full text of the sourcecites Hwu et al., 1998 source
plaindirect- Asserted: passes — The authors put it forward as true.
- Checkable: passes — It can be checked against evidence.
- Load-bearing: passes — The paper’s conclusions depend on it.
- Based: passes — The paper gives a reason why it holds.
Probably not a substantial claim. It may state two separate claims as one.
The authors state this as an assumption.
The adsorbed organic matter responsible for background methane production is oleate or an intermediate of its degradation.
“possibly oleate or an intermediate of its degradation, e.g.stearate that was degraded at a maximum rate of 99 mlCH 4(STP) /gVS.day.”
“The high values of background methane production obtained for both sludges at the end of the operation indicate that adsorbed organic mat-ter, possibly oleate or an intermediate of its degradation is still available for degradation.”
The paper relies on this without support.
The two anaerobic fixed-bed units (RI and RII) were similar enough that differences in sludge behavior can be attributed to substrate composition (lipids vs non-fat).
“Oleic acid toxicity and biodegradability were followed during long-term operation of two similar anaerobic ®xed-bed units.”
The paper relies on this without support.
The batch toxicity and biodegradability assays reflect the behavior of the sludge in the continuous fixed-bed reactors.
“Methanogenic toxicity and biodegradability tests were performed using a pressure transducer technique (Colleran et al., 1992;Colleran and Pistilli, 1994).”
The paper relies on this without support.
The threshold concentration of oleate below which adaptation occurs is a real and relevant phenomenon.
“Both tolerance to toxicity and biodegradability of oleic acid were improved by acclimatization with lipids or oleate below a threshold concentration.”
The paper relies on this without support.
The sludge samples taken from the reactors are representative of the reactor biomass at the time of sampling.
“The ®xed-bed reactors were specially designed to allow the biomass to be periodically withdrawn (Alves et al., 1998).”
Citations
Cites
Conversion processes in anaerobic digestion
Gujer, W., & Zehnder, A. J. B. (1983) · Water Science and Technology · doi:10.2166/wst.1983.0164 · Cited by 719
Mechanism of inhibition caused by long‐chain fatty acids in anaerobic digestion process
Hanaki, K., Matsuo, T., & Nagase, M. (1981) · Biotechnology and Bioengineering · doi:10.1002/bit.260230717 · Cited by 329
Effects of free long-chain fatty acids on thermophilic-anaerobic digestion
Angelidaki, I., & Ahring, B. K. (1992) · Applied Microbiology and Biotechnology · doi:10.1007/bf00174850 · Cited by 268
Galbraith, H., Miller, T. B., Paton, A. M., & Thompson, J. K. (1971) · Journal of Applied Bacteriology · doi:10.1111/j.1365-2672.1971.tb01019.x · Cited by 255
Inhibition of methanogenesis from acetate in granular sludge by long-chain fatty acids
Koster, I. W., & Cramer, A. (1987) · Applied and Environmental Microbiology · doi:10.1128/aem.53.2.403-409.1987 · Cited by 228
Bactericidal effect of long chain fatty acids in anaerobic digestion
Rinzema, A., Boone, M., van Knippenberg, K., & Lettinga, G. (1994) · Water Environment Research · doi:10.2175/wer.66.1.7 · Cited by 223
Comparative toxicity of long-chain fatty acid to anaerobic sludges from various origins
Hwu, C.-S., Donlon, B. A., & Lettinga, G. (1996) · Water Science & Technology · doi:10.1016/0273-1223(96)00665-8 · Cited by 146
Physicochemical Effects of Long Chain Fatty Acids on Bacterial Cells and their Protoplasts
Galbraith, H., & Miller, T. B. (1973) · Journal of Applied Bacteriology · doi:10.1111/j.1365-2672.1973.tb04150.x · Cited by 146
Biosorption of long-chain fatty acids in UASB treatment process
Hwu, C.-S., Tseng, S.-K., Yuan, C.-Y., Kulik, Z., & Lettinga, G. (1998) · Water Research · doi:10.1016/s0043-1354(97)00352-7 · Cited by 142
The effect of C18 unsaturated fatty acids on methane production in vitro by mixed rumen bacteria
Demeyer, D. I., & Henderickx, H. K. (1967) · Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism · doi:10.1016/0005-2760(67)90130-0 · Cited by 141
Hwu, C.-S., & Lettinga, G. (1997) · Enzyme and Microbial Technology · doi:10.1016/s0141-0229(97)00050-1 · Cited by 138
Colleran, E., Concannon, F., Golden, T., Geoghegan, F., Crumlish, B., Killilea, E., Henry, M., & Coates, J. (1992) · Water Science and Technology · doi:10.2166/wst.1992.0136 · Cited by 109
Biochemical mechanisms in the methane fermentation of glutamic and oleic acids
Weng, C.-N., & Jeris, J. S. (1976) · Water Research · doi:10.1016/0043-1354(76)90151-2 · Cited by 91
Prevention of lipid inhibition in anaerobic processes by introducing a two-phase system
Komatsu, T., Hanaki, K., & Matsuo, T. (1991) · Water Science and Technology · doi:10.2166/wst.1991.0570 · Cited by 51
Hwu, C.-S., Molenaar, G., Garthoff, J., van Lier, J. B., & Lettinga, G. (1997) · Biotechnology Letters · doi:10.1023/a:1018344127057 · Cited by 26
A new method to study interactions between biomass and packing material in anaerobic filters
Alves, M. M., Pereira, M. A., Bellouti, M., Álvares Pereira, R. M., Mota Vieira, J. A., Novais, J., & Mota, M. (1998) · Biotechnology Techniques · doi:10.1023/a:1008846113447 · Cited by 5
Self-citation(1994) · Annals of Microbiology
Research works printed but not linked: 1
- Hanaki, 1983, Inhibitory and stimulative effects of oleate on methanogenesis from acetate in anaerobic digestion, Technological Report Tohoku University, 48, 123
Cited by
Sorted by citations
Inhibition of anaerobic digestion process: A review
Chen, Y., Cheng, J. J., & Creamer, K. S. (2007) · Bioresource Technology · doi:10.1016/j.biortech.2007.01.057 · Cited by 5,063
Principles and potential of the anaerobic digestion of waste-activated sludge
Appels, L., Baeyens, J., Degrève, J., & Dewil, R. (2008) · Progress in Energy and Combustion Science · doi:10.1016/j.pecs.2008.06.002 · Cited by 3,354
Reviewing the anaerobic digestion of food waste for biogas production
Zhang, C., Su, H., Baeyens, J., & Tan, T. (2014) · Renewable and Sustainable Energy Reviews · doi:10.1016/j.rser.2014.05.038 · Cited by 1,405
Toxicants inhibiting anaerobic digestion: A review
Chen, J. L., Ortiz, R., Steele, T. W. J., & Stuckey, D. C. (2014) · Biotechnology Advances · doi:10.1016/j.biotechadv.2014.10.005 · Cited by 617
Anaerobic digestion of lipid-rich waste—Effects of lipid concentration
Cirne, D. G., Paloumet, X., Björnsson, L., Alves, M. M., & Mattìasson, B. (2006) · Renewable Energy · doi:10.1016/j.renene.2006.04.003 · Cited by 507
Self-citation
Metadata
- Authors
- Alves, M. M., Mota Vieira, J. A., Álvares Pereira, R. M., Pereira, M. A., & Mota, M.
- Affiliations
- Universidade do Minho Centro de Engenharia Biológica (PT)
- Corresponding author
- Mota, M
- Venue
- Water Research
- Publisher
- Elsevier BV
- Published
- 2001-01
- Volume
- 35
- Issue
- 1
- Pages
- 264-270
- ISSN
- 0043-1354 (ISSN-L)
- OpenAlex
- W2151644418
- Cited by
- 163
- References
- 17
- Citations by year
- 2026: 4 · 2025: 2 · 2024: 1 · 2023: 3 · 2022: 5 · 2021: 7 · 2020: 8 · 2019: 6 · 2018: 7 · 2017: 7 · 2016: 13 · 2015: 7 · 2014: 8 · 2013: 8 · 2012: 12
- FWCI
- 4.79
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Locations
- Water Research (publishedVersion)
- PubMed (publishedVersion)
- RepositóriUM (Universidade do Minho) (submittedVersion, other-oa)
- Portuguese National Funding Agency for Science, Research and Technology (RCAAP Project by FCT) (submittedVersion, cc-by-nc-nd)
- Topics
- Physical Sciences › Energy › Renewable Energy, Sustainability and the Environment › Anaerobic Digestion and Biogas Production
- Physical Sciences › Environmental Science › Environmental Chemistry › Environmental Chemistry and Analysis
- Physical Sciences › Environmental Science › Environmental Engineering › Microbial Fuel Cells and Bioremediation
- Keywords
- oleic acid, lipotoxicity, anaerobic fixed-bed reactor, biodegradability, sludge acclimatization, long-chain fatty acids, methane production, anaerobic digestion
- MeSH terms
- Biodegradation, Environmental, Kinetics, Methane, Sewage, Stearic Acids, Biomass, Bioreactors, Oleic Acid, Euryarchaeota
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.
A language model drew the claims from the paper on 2026-11-09, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).
A second model labelled each claim on 2026-11-09 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).
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