title: Thermopressurized diluted phosphoric acid pretreatment of ligno(hemi)cellulose to make free sugars and nutraceutical oligosaccharides.
abstract: Ligno(hemi)cellulosics (L(h)Cs) as sugarcane bagasse and loblolly pine sawdust are currently being used to produce biofuels such as bioethanol and biobutanol through fermentation of free sugars that are often obtained enzymatically. However, this bioconversion requires a pretreatment to solubilize the hemicellulose fractions, thus facilitating the action of the cellulolytic enzymes. Instead of the main free monosaccharides used in these current models, the modulation of thermopressurized orthophosphoric acid as a pretreatment, in the ranges of 3-12 atm and pH 1.5-2.5, can produce nondigestible oligosaccharides (NDOS) such as xylo-oligosaccharides (XOS) because heteroxylan is present in both types of hardwood and softwood hemicelluloses. A comparative thin-layer chromatographic analysis of the hydrolytic products showed the best conditions for NDOS production to be 7 atm/water, pH 2.25 and 2.50, and 8.5 atm/water for both sources. Particular hydrolysates from 7 atm (171 °C) at pHs 2.25 and 2.50 both for cane bagasse and pine sawdust, with respective oligosaccharide contents of 57 and 59 %, once mixed in a proportion of 1:1 for each plant source, were used in vitro as carbon sources for Bifidobacterium or Lactobacillus. Once both bacteria attained the stationary phase of growth, an unforeseen feature emerged: the preference of B. animalis for bagasse hydrolysates and, conversely, the preference of L. casei for pine hydrolysates. Considering the fact that nutraceutical oligosaccharides from both hemicelluloses correspond to higher value-added byproducts, the technology using a much diluted thermopressurized orthophosphoric acid pretreatment becomes an attractive choice for L(h)Cs.
authors.affiliation: Department of Pharmacy, Federal University of Paraná (UFPR), Curitiba, PR, 80210-170, Brazil.
authors.forename: Marcela
authors.initials: M
authors.lastname: Tiboni
authors.forename: Adelia
authors.initials: A
authors.lastname: Grzybowski
authors.forename: Gizele Rejane
authors.initials: GR
authors.lastname: Baldo
authors.forename: Edson Flausino
authors.initials: EF
authors.lastname: Dias
authors.forename: Robert D
authors.initials: RD
authors.lastname: Tanner
authors.forename: Julia Ann
authors.initials: JA
authors.lastname: Kornfield
authors.forename: José Domingos
authors.initials: JD
authors.lastname: Fontana
mesh_terms: D001644:Bifidobacterium / Q000254:growth & development / Q000378:metabolism; D056804:Biofuels; D050260:Carbohydrate Metabolism; D002482:Cellulose / Q000737:chemistry / Q000378:metabolism; D005285:Fermentation; D006358:Hot Temperature; D006868:Hydrolysis; D007778:Lactobacillus / Q000254:growth & development / Q000378:metabolism; D008031:Lignin / Q000378:metabolism*; D009005:Monosaccharides / Q000378:metabolism; D009844:Oligosaccharides / Q000378:metabolism*; D010756:Phosphoric Acids; D028223:Pinus / Q000737:chemistry; D011134:Polysaccharides / Q000378:metabolism; D011312:Pressure; D019936:Probiotics / Q000378:metabolism*; D031786:Saccharum / Q000737:chemistry; D014934:Wood / Q000378:metabolism
chemical_list: D056804:Biofuels; D009005:Monosaccharides; D009844:Oligosaccharides; D010756:Phosphoric Acids; D011134:Polysaccharides; C036909:lignocellulose; C007916:hemicellulose; D002482:Cellulose; D008031:Lignin; C027433:bagasse; C030242:phosphoric acid
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