The Experts below are selected from a list of 1629 Experts worldwide ranked by ideXlab platform
Ana M R B Xavier - One of the best experts on this subject based on the ideXlab platform.
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Two-Stage Aeration Fermentation Strategy to Improve Bioethanol Production by Scheffersomyces stipitis
Fermentation, 2018Co-Authors: Tiago M. Henriques, Susana R. Pereira, Luísa S. Serafim, Ana M R B XavierAbstract:Hardwood spent sulfite liquor (HSSL) is a by-product from pulp industry with a high concentration of pentose sugars, besides some hexoses suitable for bioethanol production by Scheffersomyces stipitis. The establishment of optimal aeration process conditions that results in specific microaerophilic conditions required by S. stipitis is the main challenge for ethanol production. The present study aimed to improve the ethanol production from HSSL by S. stipitis through a two-stage aeration fermentation. Experiments with controlled dissolved oxygen tension (DOT) in the first stage and oxygen restriction in the second stage were carried out. The best results were obtained with DOT control at 50% in the first stage, where the increase of oxygen availability provided faster growth and higher biomass yield, and no oxygen supply with an agitation rate of 250 rpm, in the second stage allowed a successful induction of ethanol production. Fermentation using 60% of HSSL (v/v) as substrate for S. stipitis provided a maximum specific growth rate of 0.07 h−1, an ethanol productivity of 0.04 g L h−1 and an ethanol yield of 0.39 g g−1, respectively. This work showed a successful two-stage aeration strategy as a promising aeration alternative for bioethanol production from HSSL by S. stipitis.
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Adaptation of Scheffersomyces stipitis
Biotechnology for biofuels, 2015Co-Authors: Susana R. Pereira, Violeta Sànchez I Nogué, Cláudio J R Frazão, Luísa S. Serafim, Marie F. Gorwa-grauslund, Ana M R B XavierAbstract:Background Hardwood spent sulfite liquor (HSSL) is a by-product of acid sulfite pulping process that is rich in xylose, a monosaccharide that can be fermented to ethanol by Scheffersomyces stipitis. However, HSSL also contains acetic acid and lignosulfonates that are inhibitory compounds of yeast growth. The main objective of this study was the use of an evolutionary engineering strategy to obtain variants of S. stipitis with increased tolerance to HSSL inhibitors while maintaining the ability to ferment xylose to ethanol.
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adaptation of Scheffersomyces stipitis to hardwood spent sulfite liquor by evolutionary engineering
Biotechnology for Biofuels, 2015Co-Authors: Susana R. Pereira, Violeta Sànchez I Nogué, Cláudio J R Frazão, Luísa S. Serafim, Mariefrancoise Gorwagrauslund, Ana M R B XavierAbstract:Background Hardwood spent sulfite liquor (HSSL) is a by-product of acid sulfite pulping process that is rich in xylose, a monosaccharide that can be fermented to ethanol by Scheffersomyces stipitis. However, HSSL also contains acetic acid and lignosulfonates that are inhibitory compounds of yeast growth. The main objective of this study was the use of an evolutionary engineering strategy to obtain variants of S. stipitis with increased tolerance to HSSL inhibitors while maintaining the ability to ferment xylose to ethanol.
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Biological treatment of eucalypt spent sulphite liquors: A way to boost the production of second generation bioethanol
Bioresource technology, 2011Co-Authors: Susana R. Pereira, Luísa S. Serafim, Špela Ivanuša, Dmitry V. Evtuguin, Ana M R B XavierAbstract:Abstract The fermentation of reducing sugars from hardwood (eucalypt) spent sulphite liquor (HSSL) into ethanol by Pichia ( Scheffersomyces ) stipitis is hindered by concomitant inhibitors of microbial metabolism. The conditions for the HSSL biological treatment step by Paecilomyces variotii were evaluated and optimised. Two different strategies of reactor operation were compared using single batch (B) and sequential batch reactor (SBR). Biological treatment of HSSL in the SBR revealed the best results with respect to the removal of microbial inhibitors. Also, most of inhibitory compounds, acetic acid, gallic acid, pyrogallol, amongst others, were removed from HSSL by P. variotii before the ethanol fermentation. The bio-detoxified HSSL was subjected to a successful fermentation by P. stipitis , attaining a maximum ethanol concentration of 2.4 g L −1 with a yield of 0.24 g ethanol g sugars −1 .
Susana R. Pereira - One of the best experts on this subject based on the ideXlab platform.
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Two-Stage Aeration Fermentation Strategy to Improve Bioethanol Production by Scheffersomyces stipitis
Fermentation, 2018Co-Authors: Tiago M. Henriques, Susana R. Pereira, Luísa S. Serafim, Ana M R B XavierAbstract:Hardwood spent sulfite liquor (HSSL) is a by-product from pulp industry with a high concentration of pentose sugars, besides some hexoses suitable for bioethanol production by Scheffersomyces stipitis. The establishment of optimal aeration process conditions that results in specific microaerophilic conditions required by S. stipitis is the main challenge for ethanol production. The present study aimed to improve the ethanol production from HSSL by S. stipitis through a two-stage aeration fermentation. Experiments with controlled dissolved oxygen tension (DOT) in the first stage and oxygen restriction in the second stage were carried out. The best results were obtained with DOT control at 50% in the first stage, where the increase of oxygen availability provided faster growth and higher biomass yield, and no oxygen supply with an agitation rate of 250 rpm, in the second stage allowed a successful induction of ethanol production. Fermentation using 60% of HSSL (v/v) as substrate for S. stipitis provided a maximum specific growth rate of 0.07 h−1, an ethanol productivity of 0.04 g L h−1 and an ethanol yield of 0.39 g g−1, respectively. This work showed a successful two-stage aeration strategy as a promising aeration alternative for bioethanol production from HSSL by S. stipitis.
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Adaptation of Scheffersomyces stipitis
Biotechnology for biofuels, 2015Co-Authors: Susana R. Pereira, Violeta Sànchez I Nogué, Cláudio J R Frazão, Luísa S. Serafim, Marie F. Gorwa-grauslund, Ana M R B XavierAbstract:Background Hardwood spent sulfite liquor (HSSL) is a by-product of acid sulfite pulping process that is rich in xylose, a monosaccharide that can be fermented to ethanol by Scheffersomyces stipitis. However, HSSL also contains acetic acid and lignosulfonates that are inhibitory compounds of yeast growth. The main objective of this study was the use of an evolutionary engineering strategy to obtain variants of S. stipitis with increased tolerance to HSSL inhibitors while maintaining the ability to ferment xylose to ethanol.
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adaptation of Scheffersomyces stipitis to hardwood spent sulfite liquor by evolutionary engineering
Biotechnology for Biofuels, 2015Co-Authors: Susana R. Pereira, Violeta Sànchez I Nogué, Cláudio J R Frazão, Luísa S. Serafim, Mariefrancoise Gorwagrauslund, Ana M R B XavierAbstract:Background Hardwood spent sulfite liquor (HSSL) is a by-product of acid sulfite pulping process that is rich in xylose, a monosaccharide that can be fermented to ethanol by Scheffersomyces stipitis. However, HSSL also contains acetic acid and lignosulfonates that are inhibitory compounds of yeast growth. The main objective of this study was the use of an evolutionary engineering strategy to obtain variants of S. stipitis with increased tolerance to HSSL inhibitors while maintaining the ability to ferment xylose to ethanol.
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Biological treatment of eucalypt spent sulphite liquors: A way to boost the production of second generation bioethanol
Bioresource technology, 2011Co-Authors: Susana R. Pereira, Luísa S. Serafim, Špela Ivanuša, Dmitry V. Evtuguin, Ana M R B XavierAbstract:Abstract The fermentation of reducing sugars from hardwood (eucalypt) spent sulphite liquor (HSSL) into ethanol by Pichia ( Scheffersomyces ) stipitis is hindered by concomitant inhibitors of microbial metabolism. The conditions for the HSSL biological treatment step by Paecilomyces variotii were evaluated and optimised. Two different strategies of reactor operation were compared using single batch (B) and sequential batch reactor (SBR). Biological treatment of HSSL in the SBR revealed the best results with respect to the removal of microbial inhibitors. Also, most of inhibitory compounds, acetic acid, gallic acid, pyrogallol, amongst others, were removed from HSSL by P. variotii before the ethanol fermentation. The bio-detoxified HSSL was subjected to a successful fermentation by P. stipitis , attaining a maximum ethanol concentration of 2.4 g L −1 with a yield of 0.24 g ethanol g sugars −1 .
Fengli Hui - One of the best experts on this subject based on the ideXlab platform.
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Three new Scheffersomyces species associated with insects and rotting wood in China.
MycoKeys, 2020Co-Authors: Ran-ran Jia, Chun-yue Chai, Fengli HuiAbstract:Three species of Scheffersomyces were identified during a diversity study of yeasts. All three are associated with insects and rotting wood in China. Phylogenetic analyses of a genomic dataset combining ITS and nrLSU revealed that these new collections are distinct from known species, thus three new species are introduced i.e. S. jinghongensis, S. paraergatensis, and S. anoplophorae. In our phylogenetic analyses, Scheffersomyces jinghongensis possesses a strong independent lineage and is closely related to S. titanus. S. paraergatensis is closely related to S. ergatensis, while S. anoplophorae is related to S. stambukii. Several differences in physiological traits and molecular data indicate that S. jinghongensis, S. paraergatensis, and S. anoplophorae are three newly identified species.
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Taxonomy and physiological characterisation of Scheffersomyces titanus sp. nov., a new D-xylose-fermenting yeast species from China.
Scientific reports, 2016Co-Authors: Xiao-jing Liu, Yong-cheng Ren, Wan-nan Cao, Zheng Liu, Fengli HuiAbstract:Three strains of a d-xylose-fermenting yeast species were isolated from the host beetle Dorcus titanus collected from two different localities in Henan Province, Central China. These strains formed two hat-shaped ascospores in conjugated and deliquescent asci. Multilocus phylogenetic analysis that included the nearly complete small subunit (SSU), the internal transcribed spacer (ITS) region and the D1/D2 domains of the large subunit (LSU) rDNAs, as well as RNA polymerase II largest subunit (RPB1) gene demonstrated that these strains represent a novel yeast species belonging to the genus Scheffersomyces. The phylogenetic analysis based on the nucleotide sequences of the xylose reductase (XYL1) gene supported the view that the new strains could be grouped as a unique species. Although this new species is highly similar to Scheffersomyces stipitis-like yeasts in terms of nrDNA sequences and morphological and physiological characteristics, the species can be clearly differentiated from its close relatives on the basis of the sequences of XYL1 and RPB1. Therefore, a novel yeast species, Scheffersomyces titanus sp. nov., is proposed to accommodate these strains. The type strain is NYNU 14712T (CICC 33061T = CBS 13926T).
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Description of Scheffersomyces henanensis sp. nov., a New D-Xylose-Fermenting Yeast Species Isolated from Rotten Wood
PloS one, 2014Co-Authors: Yong-cheng Ren, Liang Chen, Qiuhong Niu, Fengli HuiAbstract:Two strains of a D-xylose-fermenting yeast species were isolated from rotten wood samples collected from the Baotianman Nature Reserve in Henan Province, central China. These strains formed hat-shaped ascospores in conjugated and deliquescent asci. Multilocus phylogenetic analysis that included the nearly complete small subunit (SSU), the internal transcribed spacer (ITS) region and the D1/D2 domain of the large subunit (LSU) rRNA genes, as well as RNA polymerase II largest subunit (RPB1) gene demonstrated that the two strains represent a novel yeast species closely related to Scheffersomyces segobiensis. A sequence comparison of xylose reductase (XYL1) gene, which was recently recommended for rapid identification of cryptic species in the Scheffersomyces clade, revealed a significant sequence divergence of 25 nucleotides between the novel strains and their closest relative S. segobiensis, supporting their classification as a distinct species. Furthermore, these new strains can be clearly distinguished from S. segobiensis by a number of morphological and physiological characteristics. Therefore, a novel yeast species, Scheffersomyces henanensis sp. nov., is proposed to accommodate these strains. The type strain is BY-41T ( = CICC 1974T = CBS 12475T).
Kelly J. Dussán - One of the best experts on this subject based on the ideXlab platform.
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Bioethanol Production From Sugarcane Bagasse Hemicellulose Hydrolysate by Immobilized S. shehatae in a Fluidized Bed Fermenter Under Magnetic Field
BioEnergy Research, 2019Co-Authors: Kelly J. Dussán, Victor Haber Perez, Oselys Rodriguez Justo, Geraldo F. David, Euripedes Garcia Silveira Junior, Silvio S. SilvaAbstract:Bioethanol production from sugarcane bagasse hemicellulosic hydrolysate using immobilized Scheffersomyces shehatae on magnetic biosupports in a fluidized bed bioreactor assisted by magnetic field has been studied. Fermentations were carried out in two experimental setups operating in a magnetically stabilized bed mode with transversal and axial magnetic field lines at 8 and 12 kA/m, respectively. The best results were attained when experiments were carried out using a fermenter assisted by axial field whose ethanol/substrate yield and ethanol productivity were 0.15 ± 0.8E-3 g/g and 0.055 ± 0.3E-3 g/gh. These values were 12 and 34%, respectively, higher than those observed in fermentations with transversal field lines (Tukey’s test, p
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bioethanol production from sugarcane bagasse hemicellulose hydrolysate by immobilized s shehatae in a fluidized bed fermenter under magnetic field
Bioenergy Research, 2019Co-Authors: Kelly J. Dussán, Victor Haber Perez, Oselys Rodriguez Justo, Geraldo F. David, Euripedes Garcia Silveira, Silvio Silvério Da SilvaAbstract:Bioethanol production from sugarcane bagasse hemicellulosic hydrolysate using immobilized Scheffersomyces shehatae on magnetic biosupports in a fluidized bed bioreactor assisted by magnetic field has been studied. Fermentations were carried out in two experimental setups operating in a magnetically stabilized bed mode with transversal and axial magnetic field lines at 8 and 12 kA/m, respectively. The best results were attained when experiments were carried out using a fermenter assisted by axial field whose ethanol/substrate yield and ethanol productivity were 0.15 ± 0.8E-3 g/g and 0.055 ± 0.3E-3 g/gh. These values were 12 and 34%, respectively, higher than those observed in fermentations with transversal field lines (Tukey’s test, p < 0.05). Thus, these results are attractive and can be considered as a technological advance in the bioethanol production from biomass using this unconventional fermentation technology.
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Production of bioethanol in sugarcane bagasse hemicellulosic hydrolysate by Scheffersomyces parashehatae, Scheffersomyces illinoinensis and Spathaspora arborariae isolated from Brazilian ecosystems
Journal of applied microbiology, 2017Co-Authors: Raquel M. Cadete, Fátima De Cássia Oliveira Gomes, Kelly J. Dussán, M.a. Melo‐cheab, Rita C. L. B. Rodrigues, S. S. Da Silva, Carlos A RosaAbstract:AIMS This study aimed to evaluate new d-xylose-fermenting yeasts from Brazilian ecosystems for the production of second-generation ethanol. METHODS AND RESULTS d-xylose-fermenting yeasts isolated from rotting wood and wood-boring insects were identified as the species Scheffersomyces parashehatae, Scheffersomyces illinoinensis, Spathaspora arborariae and Wickerhamomyces rabaulensis. Among the yeasts tested, those of Sc. parashehatae exhibited the highest ethanol production when cultivated on complex medium (Yp/set = 0·437 g g-1 ). Sheffersomyces illinoinensis and Sp. arborariae showed similar ethanol production in this assay (Yp/set up to 0·295 g g-1 ). In contrast, in sugarcane bagasse hemicellulosic hydrolysate, Sc. parashehatae and Sc. illinoinensis exhibited similar ethanol production (Yp/set up to 0·254 g g-1 ), whereas Sp. arborariae showed the lowest results (peak Yp/set = 0·160 g g-1 ). Wickerhamomyces rabaulensis exhibited a remarkable xylitol production (Yp/sxyl = 0·681 g g-1 ), but producing low levels of ethanol (Yp/set = 0·042 g g-1 ). CONCLUSIONS The novel d-xylose-fermenting yeasts showed promising metabolic characteristics for use in fermentation processes for second-generation ethanol production, highlighting the importance of bioprospecting research of micro-organisms for biotechnological applications. SIGNIFICANCE AND IMPACT OF THE STUDY This study widens the scope for future researches that may examine the native yeasts presented, as limited studies have investigated these species previously.
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evaluation of oxygen availability on ethanol production from sugarcane bagasse hydrolysate in a batch bioreactor using two strains of xylose fermenting yeast
Renewable Energy, 2016Co-Authors: Kelly J. Dussán, Débora Danielle Virgínio Da Silva, Victor Haber Perez, Silvio Silvério Da SilvaAbstract:Ethanol production from biomass-derived pentose sugar challenges the development of low cost technologies to produce 2G ethanol. Although some studies describe ethanol production from yeast, few reports describe its manufacturing from hemicelluloses sugars in stirred-tank fermenter under controlled conditions. Experimental assays were performed to evaluate the influence of aeration, agitation rate and initial pH on ethanol production using sugarcane bagasse hemicelluloses hydrolysate by Scheffersomyces stipitis NRRL Y-7124 and Scheffersomyces shehatae UFMG HM 52.2. Ethanol production from these two yeasts was favored by initial pH increase and agitation rate decrease. The maximum fermentative yield was attained by S. stipitis and S. shehatae yeasts at 100 RPM, initial pH 6.50 and under oxygen limited conditions (0.1 and 3.2 h−1). Yield, ethanol productivity and process efficiency in S. shehatae and S. stipitis were 0.42 and 0.16 g g−1, 0.25 and 0.1 g L−1 h−1 and 85 and 31%, respectively. It showed that S. shehatae presented the best ethanol production performance. The current study is the first report describing the influence of these variables on hemicelluloses hydrolysates under controlled conditions. It highlights these xylose-fermenting yeasts potential to produce ethanol from biomass.
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Adaptation of Scheffersomyces Stipitis Cells as a Strategy to the Improvement of Ethanol Production from Sugarcane Bagasse Hemicellulosic Hydrolysate
Chemical engineering transactions, 2014Co-Authors: Débora Danielle Virgínio Da Silva, Priscila Vaz De Arruda, Kelly J. Dussán, Maria Das Graças De Almeida FelipeAbstract:Sugarcane bagasse, a co-product from sugar mills in Brazil, is a biomass constituted by cellulose and hemicellulose, rich in carbohydrates like pentoses (xylose and arabinose) and hexose (glucose, manose and galactose). Acid hydrolysis with diluted H2SO4 has been used to the release of sugars, resulting also in the generation of by-products such as acetic acid, furfural, hydroxymethylfurfural, phenols that are potential fermentation inhibitors and affect the growth rate of Scheffersomyces stipitis. The inhibition may occur by the action of multiple factors, such as interference in enzymatic activities, since these compounds can act synergistically or alone. Detoxification strategies have been evaluated to remove these inhibitory compounds, but they usually result in sugar and hydrolysate volume loss besides adding costs to the process. Therefore, the adaptation techniques of microorganisms could be used as a strategy to increase the fermentability of hydrolysates. In this context, the current study aims to evaluate the adaptation of Scheffersomyces stipitis cells in different ratios (25 %, 50 %, 75 % and 100 %) of non-detoxified sugarcane bagasse hemicellulosic hydrolysate and subsequently to use this adapted cells in detoxified hydrolysate for ethanol production. Inoculum adaptation was accomplished by sequential transfer of culture samples to adaptation media containing concentrations of non-detoxified hydrolysate from 25 to 100 % (25, 50, 75 and 100 %). The adapted and non-adapted cells were cultured in hydrolysate detoxified by flocculation with vegetal polymer and supplemented at 30 °C, 200 rpm for 72h in a 125 mL Erlenmeyer flasks containing 50 mL medium. The cell adaptation technique improved the bioconversion of xylose to ethanol. During the fermentation of detoxified hydrolysate using adapted cells with 50% of non-detoxified hydrolysate it can be observed a xylose consumption (98 %) and ethanol production (14.97 g L -1 ) with values of yield (YP/S), productivity (QP) and conversion efficiency of 0.33 g g -1 , 0.21 g L -1 h -1 and 64.38 %, respectively. These values of YP/S and QP were about 22 and 49% higher when compared with not- adapted cells. The adapted S. stipitis cells in 50 % of non-detoxified hydrolysate was able to ferment the detoxified sugarcane bagasse hemicellulosic hydrolysate improving ethanol production and presenting a good strategy to overcome the problems caused by the presence of toxic compounds in the hydrolysate.
Luísa S. Serafim - One of the best experts on this subject based on the ideXlab platform.
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Two-Stage Aeration Fermentation Strategy to Improve Bioethanol Production by Scheffersomyces stipitis
Fermentation, 2018Co-Authors: Tiago M. Henriques, Susana R. Pereira, Luísa S. Serafim, Ana M R B XavierAbstract:Hardwood spent sulfite liquor (HSSL) is a by-product from pulp industry with a high concentration of pentose sugars, besides some hexoses suitable for bioethanol production by Scheffersomyces stipitis. The establishment of optimal aeration process conditions that results in specific microaerophilic conditions required by S. stipitis is the main challenge for ethanol production. The present study aimed to improve the ethanol production from HSSL by S. stipitis through a two-stage aeration fermentation. Experiments with controlled dissolved oxygen tension (DOT) in the first stage and oxygen restriction in the second stage were carried out. The best results were obtained with DOT control at 50% in the first stage, where the increase of oxygen availability provided faster growth and higher biomass yield, and no oxygen supply with an agitation rate of 250 rpm, in the second stage allowed a successful induction of ethanol production. Fermentation using 60% of HSSL (v/v) as substrate for S. stipitis provided a maximum specific growth rate of 0.07 h−1, an ethanol productivity of 0.04 g L h−1 and an ethanol yield of 0.39 g g−1, respectively. This work showed a successful two-stage aeration strategy as a promising aeration alternative for bioethanol production from HSSL by S. stipitis.
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Adaptation of Scheffersomyces stipitis
Biotechnology for biofuels, 2015Co-Authors: Susana R. Pereira, Violeta Sànchez I Nogué, Cláudio J R Frazão, Luísa S. Serafim, Marie F. Gorwa-grauslund, Ana M R B XavierAbstract:Background Hardwood spent sulfite liquor (HSSL) is a by-product of acid sulfite pulping process that is rich in xylose, a monosaccharide that can be fermented to ethanol by Scheffersomyces stipitis. However, HSSL also contains acetic acid and lignosulfonates that are inhibitory compounds of yeast growth. The main objective of this study was the use of an evolutionary engineering strategy to obtain variants of S. stipitis with increased tolerance to HSSL inhibitors while maintaining the ability to ferment xylose to ethanol.
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adaptation of Scheffersomyces stipitis to hardwood spent sulfite liquor by evolutionary engineering
Biotechnology for Biofuels, 2015Co-Authors: Susana R. Pereira, Violeta Sànchez I Nogué, Cláudio J R Frazão, Luísa S. Serafim, Mariefrancoise Gorwagrauslund, Ana M R B XavierAbstract:Background Hardwood spent sulfite liquor (HSSL) is a by-product of acid sulfite pulping process that is rich in xylose, a monosaccharide that can be fermented to ethanol by Scheffersomyces stipitis. However, HSSL also contains acetic acid and lignosulfonates that are inhibitory compounds of yeast growth. The main objective of this study was the use of an evolutionary engineering strategy to obtain variants of S. stipitis with increased tolerance to HSSL inhibitors while maintaining the ability to ferment xylose to ethanol.
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Biological treatment of eucalypt spent sulphite liquors: A way to boost the production of second generation bioethanol
Bioresource technology, 2011Co-Authors: Susana R. Pereira, Luísa S. Serafim, Špela Ivanuša, Dmitry V. Evtuguin, Ana M R B XavierAbstract:Abstract The fermentation of reducing sugars from hardwood (eucalypt) spent sulphite liquor (HSSL) into ethanol by Pichia ( Scheffersomyces ) stipitis is hindered by concomitant inhibitors of microbial metabolism. The conditions for the HSSL biological treatment step by Paecilomyces variotii were evaluated and optimised. Two different strategies of reactor operation were compared using single batch (B) and sequential batch reactor (SBR). Biological treatment of HSSL in the SBR revealed the best results with respect to the removal of microbial inhibitors. Also, most of inhibitory compounds, acetic acid, gallic acid, pyrogallol, amongst others, were removed from HSSL by P. variotii before the ethanol fermentation. The bio-detoxified HSSL was subjected to a successful fermentation by P. stipitis , attaining a maximum ethanol concentration of 2.4 g L −1 with a yield of 0.24 g ethanol g sugars −1 .
