In this work, Eucalyptus grandis sawdust was subjected to steam explosion as the first step in ce... more In this work, Eucalyptus grandis sawdust was subjected to steam explosion as the first step in cellulosic ethanol production within a biorefinery approach. The effect of the moisture content in the eucalypt sawdust (8 and 50%) and pretreatment process variables, such as temperature and residence time, were evaluated along with the influence of the water washing of steam-exploded solids on enzymatic hydrolysis and C6 fermentation yields. All other process streams were characterized to evaluate the recovery yield of valuable co-products. A recovery of nearly 100% glucans in the solid fraction and 60% xylans in the liquid fraction, mainly as partially acetylated oligomers, was obtained. The best enzymatic hydrolysis efficiencies (66–67%) were achieved after pretreatment at 205 °C for 10 min. The washing of pretreated sawdust with water improved the hydrolysis efficiencies and ethanol production yields by 10% compared to the unwashed pretreated solids under the same experimental conditi...
The generation of eucalypt sawdust has increased in Uruguay with the expansion of pulp and paper ... more The generation of eucalypt sawdust has increased in Uruguay with the expansion of pulp and paper industrial sites. Currently, most of this readily available feedstock is either not used or applied for producing heat and power by combustion in biomass boilers. In this work, eucalypt sawdust was subjected to steam explosion as the first step for cellulosic ethanol production within the biorefinery concept. The effect of sawdust moisture content, pretreatment temperature and residence time were evaluated, along with the influence of water washing of steam-exploded solids on enzymatic hydrolysis and fermentation yields. After steam explosion, 60% xylans and 97% acetyl groups were recovered mainly as oligomers and acetic acid in the pretreatment liquor. Eucalypt sawdust moisture content affected the enzymatic hydrolysis performance and glucan conversion efficiency. Water washing after pretreatment improved hydrolysis efficiencies and ethanol production yields by 10% with respect to the u...
Biotechnological production of zeaxanthin by an Antarctic Flavobacterium: Evaluation of culture c... more Biotechnological production of zeaxanthin by an Antarctic Flavobacterium: Evaluation of culture conditions Eugenia Vila (Conceptualization) (Methodology) (Formal analysis) (Writing-original draft) (Project administration) (Funding acquisition), Dámaso Hornero-Méndez (Validation) (Writing-review and editing), Claudia Lareo (Writing-review and editing) (Supervision), Verónica Saravia (Conceptualization) (Methodology) (Formal analysis) (Writing-review and editing) (Supervision) (Funding acquisition
Ethanol production by the D-xylose fermentation of lignocellulosic biomass would augment environm... more Ethanol production by the D-xylose fermentation of lignocellulosic biomass would augment environmental sustainability by increasing the yield of biofuel obtained per cultivated area. A set of recombinant strains derived from the industrial strain Saccharomyces cerevisiae CAT-1 was developed for this purpose. First, two recombinant strains were obtained by the chromosomal insertion of genes involved in the assimilation and transport of D-xylose (Gal2-N376F). Strain CAT-1-XRT was developed with heterologous genes for D-xylose metabolism from the oxo-reductive pathway of Scheffersomyces stipitis (XYL1-K270R, XYL2); and strain CAT-1-XIT, with D-xylose isomerase (xylA gene, XI) from Streptomyces coelicolor. Moreover, both recombinant strains contained extra copies of homologous genes for xylulose kinase (XK) and transaldolase (TAL1). Furthermore, plasmid (pRS42K::XI) was constructed with xylA from Piromyces sp. transferred to CAT-1, CAT-1-XRT, and CAT-1-XIT, followed by an evolution protocol. After 10 subcultures, CAT-1-XIT (pRS42K::XI) consumed 74% of D-xylose, producing 12.6 g/L ethanol (0.31 g ethanol/g D-xylose). The results of this study show that CAT-1-XIT (pRS42K::XI) is a promising recombinant strain for the efficient utilization of D-xylose to produce ethanol from lignocellulosic materials. Keywords D-xylose isomerase • Bioethanol • Saccharomyces cerevisiae • Lignocellulosic biomass Highlights • CAT-1-XRT strain, with TAL1/Gal2-N376F and XYL1-K270R/XYL2 from Scheffersomyces stipitis and XKS1 in both GRE3 alleles, was not able to grow on D-xylose. • CAT-1-XIT strain, with TAL1/Gal2-N376F genes, and xylA from Streptomyces coelicolor and XKS1 in both GRE3 alleles, was not able to grow on D-xylose. • Evolved CAT-1-XRT and CAT-1-XIT with plasmid pRS42K::XI with xylA gene from Piromyces sp. had dissimilar growth on D-xylose. • Evolved CAT-1-XIT (pRS42K::XI) showed the best performance to ferment D-xylose to ethanol.
Abstract Life cycle assessments of fuel bioethanol produced in Uruguay from liquid hot water pret... more Abstract Life cycle assessments of fuel bioethanol produced in Uruguay from liquid hot water pretreated switchgrass were performed for two scenarios: the production of ethanol and electricity and a biorefinery producing ethanol, electricity, furfural, acetic, and formic acid. Experimental data and material and energy balances derived from the simulations were used to analyze the global warming potential of fuel bioethanol. Greenhouse gas (GHG) emissions in both scenarios were lower than the reference emissions for fossil fuel. The biorefinery scenario had a better performance in terms of environmental impacts, and the biofuel produced met GHG reduction requirements. Switchgrass composition, enzyme dosage, fermentation and hydrolysis efficiency, and solids content had a significant effect on environmental performance, with enzyme use being the most significant factor. A multi-objective optimization was used to find the values of solid content and enzyme dose that minimize GHG emissions and the minimum ethanol selling price (MESP). An enzyme dosage of 37 mgprotein/gglucan and solids content of 21% w/w were the optimal conditions for bioethanol production with an associated GHG value of 2 ± 5 g CO2 eq./MJethanol and a MESP of $0.84/L.
In this paper, the influence of aeration rate on the alcoholic batch fermentation of whey by Kluy... more In this paper, the influence of aeration rate on the alcoholic batch fermentation of whey by Kluyveromyces fragilis NRRL Y-2415 was investigated. Assays in 1.5-L fermentor using concentrated whey permeate containing 100 g/L of lactose were carried out at different oxygen supply rate (KLaC*) from 0 to 82 mmol/Lh. Optimum response was obtained at 14 mmol/Lh: ethanol production rate reached was 3.4 g/Lh yielding 0.46 g of product per gram of initial lactose. An increase of KLaC* from 0 to 14 mmol/Lh improved the ethanol production: maximum specific ethanol production rate (qpm) increased 3.3 times from 0.3 to 1.0 g/gh. For higher aeration levels, ethanol production diminished and biomass formation was stimulated. The declination of qpm and the increase of microns at higher aeration level lead to conclude the importance of a controlled oxygen supply in order to obtain the required balance between yeast biosynthetic needs and ethanol production.
A dataset of 30 bacterial cultures from coastal and marine areas in 2014 from sites in Fildes Pen... more A dataset of 30 bacterial cultures from coastal and marine areas in 2014 from sites in Fildes Peninsula, King George Island (Antarctica). Identification based on 16S ssu rRNA sequencing.
Nanofibrillated cellulose (NFC) extracted from biomass has potential applications in material sci... more Nanofibrillated cellulose (NFC) extracted from biomass has potential applications in material science and biomedical engineering. In this study, NFC was obtained from bleached eucalyptus Kraft pulp (BEKP) using two commercial enzyme cocktails with cellulolytic and hemicellulolytic activities and non-catalytic protein (swollenin), followed by ultrasonication. This work represents an initial study of the implementation of non-catalytic proteins along with enzymes to extract NFC from biomass. Enzymatic pretreatment was performed to partially remove hemicellulose while enhancing cellulose accessibility for NFC extraction. Cellulase pretreatment with xylanase and swollenin supplementation increased cellulose accessibility and fiber swelling due to extensive hemicellulose removal (> 80%) and fiber morphology changes. Subsequent ultrasonication was performed for cellulose nanofibrillation resulting in high NFC yields (61–97%), while keeping NFC properties almost unchanged. Through this process, cellulose nanofibers with diameters ranging from 3 nm to 10 nm were effectively isolated from BEKP, which allows to produce high quality NFC for further applications.
The energy consumption for different operative conditions and configurations of the bioethanol pr... more The energy consumption for different operative conditions and configurations of the bioethanol production industrial process from an experimental variety of sweet potato (Ipomea batatas) K 9807.1 was evaluated. A process simulation model was developed using SuperPro Designer® software. The model was based on experimental data gathered from our laboratory experiments and technology and equipment suppliers. The effects of the dry matter ratio of sweet potato to water, the fermentation efficiency, and sweet potato sugar content, on the energy consumption (steam and electricity) were respectively evaluated. All factors were significant. The best ratio of dry matter to total water to work with fresh sweet potato was 0.2 kg dry sweet potato/kg water, as for greater ratios was not found a significant reduction in energy consumption. Also, the drying of the sweet potato previous its processing was studied. It presented an energy consumption greater than the energetic content of the bioethanol produced.
Abstract The major fuels used for transportation are obtained from nonrenewable resources, such a... more Abstract The major fuels used for transportation are obtained from nonrenewable resources, such as crude oil. One alternative to these nonrenewable fuels is bioethanol. The sweet sorghum is a crop rich in sugars that can be exploited for ethanol production. From its stalks, a juice can be obtained, which contains high content of fermentable sugars that can be directly converted into ethanol, whereas the cellulose and hemicellulose rich bagasse needs to be pretreated before being fermented to ethanol. Sweet sorghum also contains starch in its grains (panicle), which is generally enzymatically hydrolyzed to glucose before its conversion into ethanol. Ethanol production processes from various parts of sweet sorghum, its technoeconomic feasibility and real-time applications are discussed in detail in the upcoming sections. Different biotechnology approaches for improving sorghum fermentation, such as biotechnology tools to improve ethanol yield from sorghum grains, solid state fermentation, simultaneous saccharification, and fermentation technology, use of mixed culture, and immobilized techniques, in bioethanol production from sweet sorghum are discussed in this chapter.
In this work, Eucalyptus grandis sawdust was subjected to steam explosion as the first step in ce... more In this work, Eucalyptus grandis sawdust was subjected to steam explosion as the first step in cellulosic ethanol production within a biorefinery approach. The effect of the moisture content in the eucalypt sawdust (8 and 50%) and pretreatment process variables, such as temperature and residence time, were evaluated along with the influence of the water washing of steam-exploded solids on enzymatic hydrolysis and C6 fermentation yields. All other process streams were characterized to evaluate the recovery yield of valuable co-products. A recovery of nearly 100% glucans in the solid fraction and 60% xylans in the liquid fraction, mainly as partially acetylated oligomers, was obtained. The best enzymatic hydrolysis efficiencies (66–67%) were achieved after pretreatment at 205 °C for 10 min. The washing of pretreated sawdust with water improved the hydrolysis efficiencies and ethanol production yields by 10% compared to the unwashed pretreated solids under the same experimental conditi...
The generation of eucalypt sawdust has increased in Uruguay with the expansion of pulp and paper ... more The generation of eucalypt sawdust has increased in Uruguay with the expansion of pulp and paper industrial sites. Currently, most of this readily available feedstock is either not used or applied for producing heat and power by combustion in biomass boilers. In this work, eucalypt sawdust was subjected to steam explosion as the first step for cellulosic ethanol production within the biorefinery concept. The effect of sawdust moisture content, pretreatment temperature and residence time were evaluated, along with the influence of water washing of steam-exploded solids on enzymatic hydrolysis and fermentation yields. After steam explosion, 60% xylans and 97% acetyl groups were recovered mainly as oligomers and acetic acid in the pretreatment liquor. Eucalypt sawdust moisture content affected the enzymatic hydrolysis performance and glucan conversion efficiency. Water washing after pretreatment improved hydrolysis efficiencies and ethanol production yields by 10% with respect to the u...
Biotechnological production of zeaxanthin by an Antarctic Flavobacterium: Evaluation of culture c... more Biotechnological production of zeaxanthin by an Antarctic Flavobacterium: Evaluation of culture conditions Eugenia Vila (Conceptualization) (Methodology) (Formal analysis) (Writing-original draft) (Project administration) (Funding acquisition), Dámaso Hornero-Méndez (Validation) (Writing-review and editing), Claudia Lareo (Writing-review and editing) (Supervision), Verónica Saravia (Conceptualization) (Methodology) (Formal analysis) (Writing-review and editing) (Supervision) (Funding acquisition
Ethanol production by the D-xylose fermentation of lignocellulosic biomass would augment environm... more Ethanol production by the D-xylose fermentation of lignocellulosic biomass would augment environmental sustainability by increasing the yield of biofuel obtained per cultivated area. A set of recombinant strains derived from the industrial strain Saccharomyces cerevisiae CAT-1 was developed for this purpose. First, two recombinant strains were obtained by the chromosomal insertion of genes involved in the assimilation and transport of D-xylose (Gal2-N376F). Strain CAT-1-XRT was developed with heterologous genes for D-xylose metabolism from the oxo-reductive pathway of Scheffersomyces stipitis (XYL1-K270R, XYL2); and strain CAT-1-XIT, with D-xylose isomerase (xylA gene, XI) from Streptomyces coelicolor. Moreover, both recombinant strains contained extra copies of homologous genes for xylulose kinase (XK) and transaldolase (TAL1). Furthermore, plasmid (pRS42K::XI) was constructed with xylA from Piromyces sp. transferred to CAT-1, CAT-1-XRT, and CAT-1-XIT, followed by an evolution protocol. After 10 subcultures, CAT-1-XIT (pRS42K::XI) consumed 74% of D-xylose, producing 12.6 g/L ethanol (0.31 g ethanol/g D-xylose). The results of this study show that CAT-1-XIT (pRS42K::XI) is a promising recombinant strain for the efficient utilization of D-xylose to produce ethanol from lignocellulosic materials. Keywords D-xylose isomerase • Bioethanol • Saccharomyces cerevisiae • Lignocellulosic biomass Highlights • CAT-1-XRT strain, with TAL1/Gal2-N376F and XYL1-K270R/XYL2 from Scheffersomyces stipitis and XKS1 in both GRE3 alleles, was not able to grow on D-xylose. • CAT-1-XIT strain, with TAL1/Gal2-N376F genes, and xylA from Streptomyces coelicolor and XKS1 in both GRE3 alleles, was not able to grow on D-xylose. • Evolved CAT-1-XRT and CAT-1-XIT with plasmid pRS42K::XI with xylA gene from Piromyces sp. had dissimilar growth on D-xylose. • Evolved CAT-1-XIT (pRS42K::XI) showed the best performance to ferment D-xylose to ethanol.
Abstract Life cycle assessments of fuel bioethanol produced in Uruguay from liquid hot water pret... more Abstract Life cycle assessments of fuel bioethanol produced in Uruguay from liquid hot water pretreated switchgrass were performed for two scenarios: the production of ethanol and electricity and a biorefinery producing ethanol, electricity, furfural, acetic, and formic acid. Experimental data and material and energy balances derived from the simulations were used to analyze the global warming potential of fuel bioethanol. Greenhouse gas (GHG) emissions in both scenarios were lower than the reference emissions for fossil fuel. The biorefinery scenario had a better performance in terms of environmental impacts, and the biofuel produced met GHG reduction requirements. Switchgrass composition, enzyme dosage, fermentation and hydrolysis efficiency, and solids content had a significant effect on environmental performance, with enzyme use being the most significant factor. A multi-objective optimization was used to find the values of solid content and enzyme dose that minimize GHG emissions and the minimum ethanol selling price (MESP). An enzyme dosage of 37 mgprotein/gglucan and solids content of 21% w/w were the optimal conditions for bioethanol production with an associated GHG value of 2 ± 5 g CO2 eq./MJethanol and a MESP of $0.84/L.
In this paper, the influence of aeration rate on the alcoholic batch fermentation of whey by Kluy... more In this paper, the influence of aeration rate on the alcoholic batch fermentation of whey by Kluyveromyces fragilis NRRL Y-2415 was investigated. Assays in 1.5-L fermentor using concentrated whey permeate containing 100 g/L of lactose were carried out at different oxygen supply rate (KLaC*) from 0 to 82 mmol/Lh. Optimum response was obtained at 14 mmol/Lh: ethanol production rate reached was 3.4 g/Lh yielding 0.46 g of product per gram of initial lactose. An increase of KLaC* from 0 to 14 mmol/Lh improved the ethanol production: maximum specific ethanol production rate (qpm) increased 3.3 times from 0.3 to 1.0 g/gh. For higher aeration levels, ethanol production diminished and biomass formation was stimulated. The declination of qpm and the increase of microns at higher aeration level lead to conclude the importance of a controlled oxygen supply in order to obtain the required balance between yeast biosynthetic needs and ethanol production.
A dataset of 30 bacterial cultures from coastal and marine areas in 2014 from sites in Fildes Pen... more A dataset of 30 bacterial cultures from coastal and marine areas in 2014 from sites in Fildes Peninsula, King George Island (Antarctica). Identification based on 16S ssu rRNA sequencing.
Nanofibrillated cellulose (NFC) extracted from biomass has potential applications in material sci... more Nanofibrillated cellulose (NFC) extracted from biomass has potential applications in material science and biomedical engineering. In this study, NFC was obtained from bleached eucalyptus Kraft pulp (BEKP) using two commercial enzyme cocktails with cellulolytic and hemicellulolytic activities and non-catalytic protein (swollenin), followed by ultrasonication. This work represents an initial study of the implementation of non-catalytic proteins along with enzymes to extract NFC from biomass. Enzymatic pretreatment was performed to partially remove hemicellulose while enhancing cellulose accessibility for NFC extraction. Cellulase pretreatment with xylanase and swollenin supplementation increased cellulose accessibility and fiber swelling due to extensive hemicellulose removal (> 80%) and fiber morphology changes. Subsequent ultrasonication was performed for cellulose nanofibrillation resulting in high NFC yields (61–97%), while keeping NFC properties almost unchanged. Through this process, cellulose nanofibers with diameters ranging from 3 nm to 10 nm were effectively isolated from BEKP, which allows to produce high quality NFC for further applications.
The energy consumption for different operative conditions and configurations of the bioethanol pr... more The energy consumption for different operative conditions and configurations of the bioethanol production industrial process from an experimental variety of sweet potato (Ipomea batatas) K 9807.1 was evaluated. A process simulation model was developed using SuperPro Designer® software. The model was based on experimental data gathered from our laboratory experiments and technology and equipment suppliers. The effects of the dry matter ratio of sweet potato to water, the fermentation efficiency, and sweet potato sugar content, on the energy consumption (steam and electricity) were respectively evaluated. All factors were significant. The best ratio of dry matter to total water to work with fresh sweet potato was 0.2 kg dry sweet potato/kg water, as for greater ratios was not found a significant reduction in energy consumption. Also, the drying of the sweet potato previous its processing was studied. It presented an energy consumption greater than the energetic content of the bioethanol produced.
Abstract The major fuels used for transportation are obtained from nonrenewable resources, such a... more Abstract The major fuels used for transportation are obtained from nonrenewable resources, such as crude oil. One alternative to these nonrenewable fuels is bioethanol. The sweet sorghum is a crop rich in sugars that can be exploited for ethanol production. From its stalks, a juice can be obtained, which contains high content of fermentable sugars that can be directly converted into ethanol, whereas the cellulose and hemicellulose rich bagasse needs to be pretreated before being fermented to ethanol. Sweet sorghum also contains starch in its grains (panicle), which is generally enzymatically hydrolyzed to glucose before its conversion into ethanol. Ethanol production processes from various parts of sweet sorghum, its technoeconomic feasibility and real-time applications are discussed in detail in the upcoming sections. Different biotechnology approaches for improving sorghum fermentation, such as biotechnology tools to improve ethanol yield from sorghum grains, solid state fermentation, simultaneous saccharification, and fermentation technology, use of mixed culture, and immobilized techniques, in bioethanol production from sweet sorghum are discussed in this chapter.
Uploads
Papers by Claudia Lareo