Parra C

Parra C
University of Concepción · Centro de Biotecnología

PhD Environmental Sciences

About

42
Publications
6,237
Reads
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1,008
Citations
Citations since 2016
10 Research Items
479 Citations
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
Additional affiliations
March 2000 - present
University of Concepción
Position
  • Resercher at LRR in Biotechnology Center

Publications

Publications (42)
Article
Full-text available
Bleached kraft pulps from eucalyptus and pine were subjected to cold caustic extraction (CCE) with NaOH (5, 10, 17.5, and 35%) for hemicelluloses removal and to increase cellulose accessibility. The effect of these changes was evaluated in enzymatic saccharification with the multicomponent Cellic CTec3 enzyme cocktail, and in viscosity reduction of...
Article
Full-text available
The objective of this study was to investigate structural changes and lignin redistribution in Eucalyptus globulus pre-treated by steam explosion under different degrees of severity (S0), in order to evaluate their effect on cellulose accessibility by enzymatic hydrolysis. Approximately 87.7% to 98.5% of original glucans were retained in the pre-tr...
Article
Full-text available
Three yeast strains were isolated from decaying wood of Chilean Valdivian forest and identified as Meyerozyma guilliermondii, Scheffersomyces coipomensis, and Sugiyamaella paludigena. These strains were able to efficiently grow on the major monomers contained in Pinus spp. and Eucalyptus spp. wood that includes glucose (Glc), xylose (Xyl), and mann...
Article
Full-text available
In order to understand the relation between chemical composition, microscopic structure and enzymatic digestibility, different Eucalyptus globulus wood pretreated samples were examined. Pretreated materials obtained by steam explosion and autohydrolysis were compared with those obtained by organosolv and kraft processes. Chemical analyses of pretre...
Chapter
Over the last century, the world has depended on the oil industry to provide the greatest majority of the raw material necessary for the production of chemical products, textiles, pharmaceuticals, and fuels. Countries with no oil reserves have the necessity to seek new cleaner and sustainable technologies to fulfill its requirements. Lignocellulosi...
Article
This work studies the contribution of each step of the steam explosion (residence time and sudden decompression) of wheat straw. Raw wheat straw and wheat straw with different xylan extraction degrees were subjected to a steam explosion without residence time at 160, 180, 200 or 220°C in order to identify the individual contribution of the sudden p...
Article
Full-text available
Cellulosic ethanol is one of the most important biotechnological products to mitigate the consumption of fossil fuels and to increase the use of renewable resources for fuels and chemicals. Short rotation woody crops (SRWC) have been proposed as the most promising raw material for cellulosic ethanol production, as a result of its several advantages...
Article
Full-text available
The combination of hemicellulose pre-hydrolysis by dilute acid or steam-explosion followed by kraft pulping was one approach evaluated in this work to generate pulps from radiata pine wood chips amenable to saccharification by enzymatic hydrolysis. Dilute acid (combined severity factor, CS = 1.67) and steam explosion (severity factor, log R-o = 4.0...
Article
Full-text available
Conditions to increase phenolic hydroxyl groups (OH-Phe) in organosolv lignin using alkaline catalysts (NaOH and KOH) were optimized with the purpose of increasing the reactivity of lignin and to evaluate the effect on the structure of the newly generated compounds as a result of the basecatalyzed depolymerization (BCD). The lignin-derived compound...
Poster
Ethanol derived from lignocellulosic biomass (LCB) has long been recognized as a potential alternative for non-renewable transportation fuels. Due to LCB recalcitrance to enzymatic hydrolysis, owing to it rigid structure, the interaction between cellulose and hemicellulose plus the degree of lignification, a pretreatment process is necessary to dis...
Article
Olive stones are an agro-industrial by-product in Mediterranean countries that can be regarded as a potential source of bio-fuels and bioactive compounds. In this work, olive stones were pretreated with liquid hot water (LHW), dilute sulphuric acid (DSA), and organosolv delignification at temperatures in the range 190ºC-230ºC. The resulting solids...
Poster
The concept of wood biorefinery is envisioned as the selective separation of the three main wood components, cellulose, hemicellulose and lignin, and the subsequent utilization of each fraction for production of fuels, high value-added chemicals and other related products. The hemicelluloses can be previously disassembled from the wood matrix befor...
Poster
Full-text available
During the pretreatment processes lignin is susceptible to condensation reactions, generating a more hydrophobic, recalcitrant and difficult to solubilize lignin. In addition, the percentage of acetyl groups in their hemicellulose is lower than in hard woods, so the extraction of the hemicelluloses is also inefficient by methods such as diluted aci...
Article
Full-text available
A highly efficient pretreatment process to break down the recalcitrant structure of Eucalyptus globulus raw material to produce ethanol was investigated. A response surface methodology was used to optimise the pretreatment parameters. The inlet parameters were temperature and time, and the response parameters were the total glucose plus xylose yiel...
Poster
Full-text available
The pulp and paper industry with its existing infrastructure provides an opportunity to expand the range of the products that are manufactured to an Integrated Forest Biorefinery. During kraft pulping, hemicelluloses are degraded into low molecular weight saccharinic acids and end up in the black liquor together with degraded lignin. To recover ene...
Article
Full-text available
Lignocellulosic biomass (LB) has been recognized as potential raw for bioethanol production. To facility LB bioconversion a pretreatment is applied, followed by simultaneous or separated saccharification and fermentation (SSF or SHF, respectively) steps. Characterization of pretreated materials, needed to evaluate their ethanol yields, involves lab...
Article
Full-text available
Fractionation of Eucalyptus globulus wood chips is mandatory for developing a biorefinery process. In order to achieve this, products released from hydrothermolysis pretreatment were studied within the severity (log R0) range 3.3–4.5. The highest solubilized xylose yield was 56% (DWB) at log R0 3.9. Values higher than log R0 4.1 have led to high xy...
Poster
Full-text available
With the purpose of achieving a high ethanol concentration, a high pretreated substrate loading is crucial for the economy of the SSF process. Working with high solid loading has a significant effect over the capital and production cost of the process due to the reduction size of the equipment, such as tanks and distillation columns, reduced energy...
Article
Full-text available
β-Glucosidase from Trichoderma reesei was immobilised on synthetic superparamagnetic magnetite (Fe3O4) nanoparticles with a mean diameter of 10 nm and were used to supplement cellulase in the enzymatic hydrolysis of three substrates: wheat straw pretreated by steam explosion, Eucalyptus globulus pretreated by hydrothermolysis and E. globulus pretre...
Article
Full-text available
White zones produced on biodegraded Pinus radiata wood chips were characterized by micro-localized-FTIR (Fourier Transformed Infra Red) spectroscopy and scanning electron microscopy. Both techniques permitted assignment of the white zones to a selective lignin removal process. Although both fungi studied have degraded lignin selectively in these re...
Article
Ethanol generation from lignocellulose materials provides an alternative energy-production system. This study investigates the effect of pre-treatment conditions: maximum temperature (range 423.15–483.15 K) and sulfuric-acid concentration (interval 0.002–0.059 kmol/m3) on fuel-ethanol production from simultaneous saccharification and fermentation (...
Article
Superparamagnetic magnetite nanoparticles (mean diameter similar to 10 nm) were synthesized using the co-precipitation route from Fe(2+)/Fe(3+) in aqueous solutions (molar ratio 1:2) by adding a base under mechanical stirring at 10.000 rpm. This stirring velocity was found to be suitable for obtaining nanoparticles of this mean size, and a decrease...
Article
The simultaneous saccharification and fermentation (SSF) process of lignocellulosic materials requires the utilization of microorganisms capable of working at high temperatures. The selection of Saccharomyces cerevisiae strains able to ferment sugars obtained from lignocellulosic material at temperatures above 35 °C with high ethanol yield has beco...
Article
Ethanol derived from biomass has the potential to be a renewable transportation fuel that can replace gasoline. The demand for oxygenated fuels is increasing rapidly. The use of bioethanol can save non-renewable energy consumption and reduce greenhouse emissions. The largest feedstock for ethanol is lignocellulosic biomass. Cellulose is intrinsical...
Article
Palo podrido (literally, rotted log) and iron chelating compounds associated with it were characterized. Field-collected samples taken from palo podrido were sorted visually into three groups representing early, and two stages of advanced delignification (termed as EDS, ADS1 and ADS2, respectively). Lignin contents in these samples were 22.3%, 5.1%...
Article
Different compounds that reduce Fe(III) and that simultaneously increase the oxidation potential of the H2O2/Fe2+ system, have been evaluated. In this work, the improving of Fenton reactions by 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DHBA) or 1,2-dihydroxybenzene (CAT) were studied. The three compounds are able to reduc...
Article
Full-text available
Drimys winteri and Nothofagus dombeyi, two native Chilean wood species with high potential for pulp production, were biodegraded by Ganoderma australe. This fungus is known to provoke extensive and selective biodelignification of these wood species in the field. Under laboratory conditions, N. dombeyi underwent higher weight and component losses th...
Article
Full-text available
Different compounds that reduce Fe(III) and that simultaneously increase the oxidation potential of the H2O2/Fe2+ system, have been evaluated. In this work, the improving of Fenton reactions by 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DHBA) or 1,2-dihydroxybenzene (CAT) were studied. The three compounds are able to reduc...
Article
Fenton reaction, which involves hydrogen peroxide and ferrous ion, has been proposed as an efficient option for effluent treatment. In this work, the treatment of a pulp bleaching effluent using Fenton-type reactions assisted by either, 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DHBA) and 1,2-dihydroxybenzene (CAT), were s...
Article
Fenton reaction, which involves hydrogen peroxide and ferrous ion, has been proposed as an efficient option for effluent treatment. In this work, the treatment of a pulp bleaching effluent using Fenton-type reactions assisted by either, 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DHBA) and 1,2-dihydroxybenzene (CAT), were s...
Article
Iron-chelating low-molecular-weight compounds or catecholate siderophores have been suggested to be involved in wood biodegradation. To help in understanding the mechanism involved in the enzyme-like activity of catecholate siderophores, the oxidative properties of 2,3-dihydroxybenzoic acid (DHBA) and 3, 4-dihydroxyphenylacetic acid (DHPAA) chelate...
Article
The properties of a siderophore model, acetohydroxamic acid (AHA), of desferral were studied. The pH, ionic strength, and AHA/Fe(III) ratios for o-dianisidine oxidation were optimized. Phenoloxidase activity of hydroxamates/Fe(III) acting on o-dianisidine at pH 7.0 and pH 3.0 was observed. Under these conditions, AHA was able to reduce Fe(III) to F...
Article
Twenty-eight samples containing Bacillus thuringiensis were obtained from 137 soil samples collected from the Maule Region of Chile. Two isolates were selected for evaluation of insecticidal activity against two agronomically important insects, according to the following criteria: colony and parasporal inclusion morphology, SDS-PAGE, Western blot,...

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Projects

Projects (3)
Project
The proposed study will investigate the production of lipids using xylose enriched hydrolysate of Eucalyptus globulus wood chips as the substrate for S. coipomoensis CB 1. The combination of statistical optimization and mutagenesis will be employed to isolate hyper lipid accumulating yeast strains for lipid production.
Archived project
Project
the assessment of the biotechnological potential of yeasts isolated from Valdivian rainforest of Chile particularly with regard to their wide applications ranging from medicinal use to the feedstock for the production of second generation biodiesel and oleochemicals.