Abstract
BACKGROUND: The search for promising and renewable sources of carbohydrates for the production of biofuels and other biorenewables has been stimulated by an increase in global energy demand in the face of growing concern over greenhouse gas emissions and fuel security. In particular, interest has focused on non-food lignocellulosic biomass as a potential source of abundant and sustainable feedstock for biorefineries. Here we investigate the potential of three Brazilian grasses (Panicum maximum, Pennisetum purpureum and Brachiaria brizantha), as well as bark residues from the harvesting of two commercial Eucalyptus clones (E. grandis and E. grandis x urophylla) for biofuel production, and compare these to sugarcane bagasse. The effects of hot water, acid, alkaline and sulfite pretreatments (at increasing temperatures) on the chemical composition, morphology and saccharification yields of these different biomass types were evaluated. RESULTS: The average yield (per hectare), availability and general composition of all five biomasses were compared. Compositional analyses indicate a high level of hemicellulose and lignin removal in all grass varieties (including sugarcane bagasse) after acid and alkaline pretreatment with increasing temperatures, whilst the biomasses pretreated with hot water or sulfite showed little variation from the control. For all biomasses, higher cellulose enrichment resulted from treatment with sodium hydroxide at 130°C. At 180°C, a decrease in cellulose content was observed, which is associated with high amorphous cellulose removal and 5-hydroxymethyl-furaldehyde production. Morphological analysis showed the effects of different pretreatments on the biomass surface, revealing a high production of microfibrillated cellulose on grass surfaces, after treatment with 1% sodium hydroxide at 130°C for 30 minutes. This may explain the higher hydrolysis yields resulting from these pretreatments, since these cellulosic nanoparticles can be easily accessed and cleaved by cellulases. CONCLUSION: Our results show the potential of three Brazilian grasses with high productivity yields as valuable sources of carbohydrates for ethanol production and other biomaterials. Sodium hydroxide at 130°C was found to be the most effective pretreatment for enhanced saccharification yields. It was also efficient in the production of microfibrillated cellulose on grass surfaces, thereby revealing their potential as a source of natural fillers used for bionanocomposites production.
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Claims 7
Claim · model-written summary
Acid and alkaline pretreatment removed a high level of hemicellulose and lignin in all grass varieties.
- Taxon
- Panicum maximum, Pennisetum purpureum and Brachiaria brizantha
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Megathyrsus maximus.jpg?width=60)
Cenchrus purpureus
Urochloa brizanthae0 - Treatment
- acid and alkaline pretreatmente1
- Outcome
- hemicellulose and lignin removale1
- Direction
- highe1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
.jpg?width=500)
Verbatim
e0“three Brazilian grasses (Panicum maximum, Pennisetum purpureum and Brachiaria brizantha)”
e1“Compositional analyses indicate a high level of hemicellulose and lignin removal in all grass varieties (including sugarcane bagasse) after acid and alkaline pretreatment with increasing temperatures”
Claim · model-written summary
Sodium hydroxide at 130°C gave higher cellulose enrichment in all biomasses.
- Taxon
- Panicum maximum, Pennisetum purpureum and Brachiaria brizanthaMegathyrsus maximusCenchrus purpureusUrochloa brizanthae0
- Treatment
- sodium hydroxide at 130°Ce2
- Outcome
- cellulose enrichmente2
- Direction
- highere2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three Brazilian grasses (Panicum maximum, Pennisetum purpureum and Brachiaria brizantha)”
e2“For all biomasses, higher cellulose enrichment resulted from treatment with sodium hydroxide at 130°C”
Claim · model-written summary
At 180°C, cellulose content decreased in the biomasses.
- Taxon
- Panicum maximum, Pennisetum purpureum and Brachiaria brizanthaMegathyrsus maximusCenchrus purpureusUrochloa brizanthae0
- Treatment
- 180°Ce3
- Outcome
- cellulose contente3
- Direction
- decreasee3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three Brazilian grasses (Panicum maximum, Pennisetum purpureum and Brachiaria brizantha)”
e3“At 180°C, a decrease in cellulose content was observed”
Claim · model-written summary
Treatment with 1% sodium hydroxide at 130°C for 30 minutes produced a high production of microfibrillated cellulose on grass surfaces.
- Taxon
- Panicum maximum, Pennisetum purpureum and Brachiaria brizanthaMegathyrsus maximusCenchrus purpureusUrochloa brizanthae0
- Organ / stage
- grass surfacese4
- Treatment
- 1% sodium hydroxide at 130°C for 30 minutese4
- Outcome
- production of microfibrillated cellulosee4
- Direction
- highe4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three Brazilian grasses (Panicum maximum, Pennisetum purpureum and Brachiaria brizantha)”
e4“a high production of microfibrillated cellulose on grass surfaces, after treatment with 1% sodium hydroxide at 130°C for 30 minutes”
Claim · model-written summary
Sodium hydroxide at 130°C was the most effective pretreatment for enhanced saccharification yields.
- Taxon
- Panicum maximum, Pennisetum purpureum and Brachiaria brizanthaMegathyrsus maximusCenchrus purpureusUrochloa brizanthae0
- Treatment
- Sodium hydroxide at 130°Ce5
- Outcome
- saccharification yieldse5
- Direction
- enhancede5
- Qualifier
- most effective pretreatmente5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three Brazilian grasses (Panicum maximum, Pennisetum purpureum and Brachiaria brizantha)”
e5“Sodium hydroxide at 130°C was found to be the most effective pretreatment for enhanced saccharification yields”
Claim · model-written summary
The three Brazilian grasses have high productivity yields as valuable carbohydrate sources for ethanol production.
- Taxon
- Panicum maximum, Pennisetum purpureum and Brachiaria brizanthaMegathyrsus maximusCenchrus purpureusUrochloa brizanthae0
- Outcome
- productivity yieldse6
- Qualifier
- highe6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three Brazilian grasses (Panicum maximum, Pennisetum purpureum and Brachiaria brizantha)”
e6“Our results show the potential of three Brazilian grasses with high productivity yields as valuable sources of carbohydrates for ethanol production”
Claim · model-written summary
The grass surfaces show potential as a source of natural fillers for bionanocomposites.
- Taxon
- Panicum maximum, Pennisetum purpureum and Brachiaria brizanthaMegathyrsus maximusCenchrus purpureusUrochloa brizanthae0
- Outcome
- potential as a source of natural fillerse7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“three Brazilian grasses (Panicum maximum, Pennisetum purpureum and Brachiaria brizantha)”
e7“revealing their potential as a source of natural fillers used for bionanocomposites production”
The same questions in other papers
alkalinity · molecular: metabolites · Urochloa brizantha (palisade grass)Positive and negative results
1 in the opposite direction
- negative
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.