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Jin Wang - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Transcriptomic Data Reveal Unexpected Regulatory Behavior of Scheffersomyces Stipitis
IFAC-PapersOnLine, 2019Co-Authors: Matthew Hilliard, Jin WangAbstract:Abstract The rapid developments in “omics” technologies offer unprecedented opportunities to help understand cellular metabolisms at genome-scale. Among different “omics” data, RNA-seq based transcriptome profiling has been used to enhance the understanding of the genome-scale response of the organism to different stimuli. While these studies have provided insightful findings, they are most often limited to studying two-steady-state conditions. From a control perspective, as cellular metabolism is a highly complex dynamic system, the transient response could offer significantly more information on the cellular metabolism, particularly on potential gene regulatory mechanisms. In this work, we present our initial results on analyzing the dynamic transcriptomic profiles of Scheffersomyces Stipitis during the transition from aerobic growth to oxygen-limited fermentation. Our results confirm that the transient states indeed offer important and significantly more information than that provided by the steady-states alone. In addition, the transient transcriptomic data revealed interesting regulatory behavior that was not expected before, which could offer crucial insight in understanding the cellular metabolism.
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elucidating redox balance shift in Scheffersomyces Stipitis fermentative metabolism using a modified genome scale metabolic model
Microbial Cell Factories, 2018Co-Authors: Matthew Hilliard, Andrew Damiani, Thomas W. Jeffries, Peter Q. He, Jin WangAbstract:Scheffersomyces Stipitis is an important yeast species in the field of biorenewables due to its desired capacity for xylose utilization. It has been recognized that redox balance plays a critical role in S. Stipitis due to the different cofactor preferences in xylose assimilation pathway. However, there has not been any systems level understanding on how the shift in redox balance contributes to the overall metabolic shift in S. Stipitis to cope with reduced oxygen uptake. Genome-scale metabolic network models (GEMs) offer the opportunity to gain such systems level understanding; however, currently the two published GEMs for S. Stipitis cannot be used for this purpose, as neither of them is able to capture the strain’s fermentative metabolism reasonably well due to their poor prediction of xylitol production, a key by-product under oxygen limited conditions. A system identification-based (SID-based) framework that we previously developed for GEM validation is expanded and applied to refine a published GEM for S. Stipitis, iBB814. After the modified GEM, named iDH814, was validated using literature data, it is used to obtain genome-scale understanding on how redox cofactor shifts when cells respond to reduced oxygen supply. The SID-based framework for GEM analysis was applied to examine how the environmental perturbation (i.e., reduced oxygen supply) propagates through the metabolic network, and key reactions that contribute to the shifts of redox and metabolic state were identified. Finally, the findings obtained through GEM analysis were validated using transcriptomic data. iDH814, the modified model, was shown to offer significantly improved performance in terms of matching available experimental results and better capturing available knowledge on the organism. More importantly, our analysis based on iDH814 provides the first genome-scale understanding on how redox balance in S. Stipitis was shifted as a result of reduced oxygen supply. The systems level analysis identified the key contributors to the overall metabolic state shift, which were validated using transcriptomic data. The analysis confirmed that S. Stipitis uses a concerted approach to cope with the stress associated with reduced oxygen supply, and the shift of reducing power from NADPH to NADH seems to be the center theme that directs the overall shift in metabolic states.
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Elucidating redox balance shift in Scheffersomyces Stipitis ’ fermentative metabolism using a modified genome-scale metabolic model
Microbial cell factories, 2018Co-Authors: Matthew Hilliard, Andrew Damiani, Thomas W. Jeffries, Jin WangAbstract:Scheffersomyces Stipitis is an important yeast species in the field of biorenewables due to its desired capacity for xylose utilization. It has been recognized that redox balance plays a critical role in S. Stipitis due to the different cofactor preferences in xylose assimilation pathway. However, there has not been any systems level understanding on how the shift in redox balance contributes to the overall metabolic shift in S. Stipitis to cope with reduced oxygen uptake. Genome-scale metabolic network models (GEMs) offer the opportunity to gain such systems level understanding; however, currently the two published GEMs for S. Stipitis cannot be used for this purpose, as neither of them is able to capture the strain’s fermentative metabolism reasonably well due to their poor prediction of xylitol production, a key by-product under oxygen limited conditions. A system identification-based (SID-based) framework that we previously developed for GEM validation is expanded and applied to refine a published GEM for S. Stipitis, iBB814. After the modified GEM, named iDH814, was validated using literature data, it is used to obtain genome-scale understanding on how redox cofactor shifts when cells respond to reduced oxygen supply. The SID-based framework for GEM analysis was applied to examine how the environmental perturbation (i.e., reduced oxygen supply) propagates through the metabolic network, and key reactions that contribute to the shifts of redox and metabolic state were identified. Finally, the findings obtained through GEM analysis were validated using transcriptomic data. iDH814, the modified model, was shown to offer significantly improved performance in terms of matching available experimental results and better capturing available knowledge on the organism. More importantly, our analysis based on iDH814 provides the first genome-scale understanding on how redox balance in S. Stipitis was shifted as a result of reduced oxygen supply. The systems level analysis identified the key contributors to the overall metabolic state shift, which were validated using transcriptomic data. The analysis confirmed that S. Stipitis uses a concerted approach to cope with the stress associated with reduced oxygen supply, and the shift of reducing power from NADPH to NADH seems to be the center theme that directs the overall shift in metabolic states.
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Using a System Identification based Framework to Elucidate How Scheffersomyces Stipitis Shifts Redox in Response to Reduced Oxygen Supply
IFAC-PapersOnLine, 2018Co-Authors: Matthew Hilliard, Andrew Damiani, Jin WangAbstract:Abstract Scheffersomyces Stipitis has been recognized as an important yeast species in the field of biorenewables due to its native capacity for utilizing xylose. It has been well-recognized that redox (im)balance plays an important role for S. Stipitis under oxygen limited conditions, in terms of ethanol production and xylitol (a by-product) production. However, there has not been any systems level understanding on how the shift in redox balance contribute to the overall metabolic shift in S. Stipitis to cope with reduced oxygen uptake. In this work, with our recently developed genome-scale metabolic model (GEM) for S. Stipitis, iDH814, we apply a system identification (SID) based framework to elucidate how the cellular metabolism of S. Stipitis shifts in response to reduced oxygen supply. The systems level analysis indicates that S. Stipitis uses a concerted approach to cope with the stress associated with reduced oxygen supply, and the shift of reducing power from NADPH to NADH seems to be the center theme that directs the overall shift in metabolic states.
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Elucidating redox balance shift in Scheffersomyces Stipitis’ fermentative metabolism using a modified genome-scale metabolic model
BMC, 2018Co-Authors: Matthew Hilliard, Andrew Damiani, Thomas Jeffries, Jin WangAbstract:Abstract Background Scheffersomyces Stipitis is an important yeast species in the field of biorenewables due to its desired capacity for xylose utilization. It has been recognized that redox balance plays a critical role in S. Stipitis due to the different cofactor preferences in xylose assimilation pathway. However, there has not been any systems level understanding on how the shift in redox balance contributes to the overall metabolic shift in S. Stipitis to cope with reduced oxygen uptake. Genome-scale metabolic network models (GEMs) offer the opportunity to gain such systems level understanding; however, currently the two published GEMs for S. Stipitis cannot be used for this purpose, as neither of them is able to capture the strain’s fermentative metabolism reasonably well due to their poor prediction of xylitol production, a key by-product under oxygen limited conditions. Results A system identification-based (SID-based) framework that we previously developed for GEM validation is expanded and applied to refine a published GEM for S. Stipitis, iBB814. After the modified GEM, named iDH814, was validated using literature data, it is used to obtain genome-scale understanding on how redox cofactor shifts when cells respond to reduced oxygen supply. The SID-based framework for GEM analysis was applied to examine how the environmental perturbation (i.e., reduced oxygen supply) propagates through the metabolic network, and key reactions that contribute to the shifts of redox and metabolic state were identified. Finally, the findings obtained through GEM analysis were validated using transcriptomic data. Conclusions iDH814, the modified model, was shown to offer significantly improved performance in terms of matching available experimental results and better capturing available knowledge on the organism. More importantly, our analysis based on iDH814 provides the first genome-scale understanding on how redox balance in S. Stipitis was shifted as a result of reduced oxygen supply. The systems level analysis identified the key contributors to the overall metabolic state shift, which were validated using transcriptomic data. The analysis confirmed that S. Stipitis uses a concerted approach to cope with the stress associated with reduced oxygen supply, and the shift of reducing power from NADPH to NADH seems to be the center theme that directs the overall shift in metabolic states
Silvio Silvério Da Silva - One of the best experts on this subject based on the ideXlab platform.
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Biosurfactants produced by Scheffersomyces Stipitis cultured in sugarcane bagasse hydrolysate as new green larvicides for the control of Aedes aegypti, a vector of neglected tropical diseases.
PloS one, 2017Co-Authors: Paulo Ricardo Franco Marcelino, Vinicius Luiz Da Silva, Rafael Rodrigues Philippini, Claudio José Von Zuben, Jonas Contiero, Júlio César Dos Santos, Silvio Silvério Da SilvaAbstract:Biosurfactants are microbial metabolites with possible applications in various industrial sectors that are considered ecofriendly molecules. In recent years, some studies identified these compounds as alternatives for the elimination of vectors of tropical diseases, such as Aedes aegypti. The major bottlenecks of biosurfactant industrial production have been the use of conventional raw materials that increase production costs as well as opportunistic or pathogenic bacteria, which restrict the application of these biomolecules. The present study shows the potential of hemicellulosic sugarcane bagasse hydrolysate as a raw material for the production of a crystalline glycolipidic BS by Scheffersomyces Stipitis NRRL Y-7124, which resulted in an emulsifying index (EI24) of 70 ± 3.4% and a superficial tension of 52 ± 2.9 mN.m-1. Additionally, a possible new application of these compounds as biolarvicides, mainly against A. aegypti, was evaluated. At a concentration of 800 mg.L-1, the produced biosurfactant caused destruction to the larval exoskeletons 12 h after application and presented an letal concentration (LC50) of 660 mg.L-1. Thus, a new alternative for biosurfactant production using vegetal biomass as raw material within the concept of biorefineries was proposed, and the potential of the crystalline glycolipidic biosurfactant in larvicidal formulations against neglected tropical disease vectors was demonstrated.
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effect of volumetric oxygen transfer coefficient kla on ethanol production performance by Scheffersomyces Stipitis on hemicellulosic sugarcane bagasse hydrolysate
Biochemical Engineering Journal, 2016Co-Authors: Débora Danielle Virgínio Da Silva, Silvio Silvério Da Silva, Kelly J. Dussán, Valentina Hernandez, Carlos A Cardona, Maria Das Graças De Almeida FelipeAbstract:Abstract Experimental evaluation of the effect of the agitation speed and aeration rate (measured by k L a) and energy required for ethanol production using sugarcane bagasse hemicellulosic hydrolysate (SBHH) by Scheffersomyces Stipitis were studied. Fermentation and purification stages were simulated using the software Aspen Plus with experimental data to understand the overall energy performance of the process. In all experiments, fermentative parameters and the thermal energy required in the ethanol production process were strongly influenced by k L a values. The optimum initial k L a to achieve the maximal ethanol concentration (15.03 g L −1 ) and the minimal thermal energy required (1.85 × 10 5 KW per kg ethanol), were found at 8.0 h −1 (450 rpm and 0.6 vvm). Under this condition, the ethanol yield and productivity were 0.37 g g −1 and 0.30 g L −1 h −1 , respectively. The current study highlights the ethanol production improvement from hemicellulose hydrolysate by S. Stipitis and will contribute to developing a more efficient strategies for fermentation of both cellulose and hemicellulose hydrolysates.
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Effect of volumetric oxygen transfer coefficient (kLa) on ethanol production performance by Scheffersomyces Stipitis on hemicellulosic sugarcane bagasse hydrolysate
Biochemical Engineering Journal, 2016Co-Authors: Débora Danielle Virgínio Da Silva, Silvio Silvério Da Silva, Kelly J. Dussán, Valentina Hernandez, Carlos A Cardona, Maria Das Graças De Almeida FelipeAbstract:Abstract Experimental evaluation of the effect of the agitation speed and aeration rate (measured by k L a) and energy required for ethanol production using sugarcane bagasse hemicellulosic hydrolysate (SBHH) by Scheffersomyces Stipitis were studied. Fermentation and purification stages were simulated using the software Aspen Plus with experimental data to understand the overall energy performance of the process. In all experiments, fermentative parameters and the thermal energy required in the ethanol production process were strongly influenced by k L a values. The optimum initial k L a to achieve the maximal ethanol concentration (15.03 g L −1 ) and the minimal thermal energy required (1.85 × 10 5 KW per kg ethanol), were found at 8.0 h −1 (450 rpm and 0.6 vvm). Under this condition, the ethanol yield and productivity were 0.37 g g −1 and 0.30 g L −1 h −1 , respectively. The current study highlights the ethanol production improvement from hemicellulose hydrolysate by S. Stipitis and will contribute to developing a more efficient strategies for fermentation of both cellulose and hemicellulose hydrolysates.
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Hemicellulosic ethanol production by immobilized cells of Scheffersomyces Stipitis: effect of cell concentration and stirring.
Bioengineered, 2015Co-Authors: Thais S. S. Milessi, Felipe A. F. Antunes, Anuj K. Chandel, Silvio Silvério Da SilvaAbstract:Bioconversion of hemicellulosic hydrolysate into ethanol plays a pivotal role in the overall success of biorefineries. For the efficient fermentative conversion of hemicellulosic hydrolysates into ethanol, the use of immobilized cells system could provide the enhanced ethanol productivities with significant time savings. Here, we investigated the effect of 2 important factors (e.g., cell concentration and stirring) on ethanol production from sugarcane bagasse hydrolysate using the yeast Scheffersomyces Stipitis immobilized in calcium alginate matrix. A 22 full factorial design of experiment was performed considering the process variables- immobilized cell concentration (3.0, 6.5 and 10.0 g/L) and stirring (100, 200 and 300 rpm). Statistical analysis showed that stirring has the major influence on ethanol production. Maximum ethanol production (8.90 g/l) with ethanol yield (Yp/s) of 0.33 g/g and ethanol productivity (Qp) of 0.185 g/l/h was obtained under the optimized process conditions (10.0 g/L of cells ...
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Immobilization of Scheffersomyces Stipitis cells with calcium alginate beads: A sustainable method for hemicellulosic ethanol production from sugarcane bagasse hydrolysate
Bioethanol, 2013Co-Authors: Thais S. S. Milessi, Felipe A. F. Antunes, Anuj K. Chandel, Silvio Silvério Da SilvaAbstract:Lignocellulosic ethanol has shown promising alternative to gasoline however expensive and cumbersome bioprocessing limits the commercialization of biofuels. The major impediment toward the economic ethanol production is the bioconversion of sugars into ethanol via microbial fermentation. Application of immobilized cells in fermentation of hemicellulosic hydrolysate could minimize the ethanol production cost. This study evaluated the conditions for cell immobilization for the yeast Scheffersomyces Stipitis NRRL Y-7124 by the method of entrapment in calcium alginate gel. A full factorial design (23) was designed to investigate the effect of three process variables i.e. sodium alginate concentration (1.0, 1.5 and 2.0%), calcium chloride concentration (0.1, 0.15 and 0.2 M) and conditioning time (12, 18 and 24 h). Twelve numbers of experiments were performed with central points in quadruplicates. The range of ethanol production in all experiments was observed from 4.88 g/L (Yp/s, 0.16 g/g) to 9.9 g/L ethanol (Yp/s, 0.29 g/g). Statistical analysis revealed that immobilization conditions (2.0% sodium alginate concentration, 0.1M calcium chloride concentration and 12 h conditioning time) were responsible for high stability of immobilized cells which in-turn enabled the maximum ethanol production (7.2 g/L, Yp/s, 0.26 g/g) from hemicellulosic hydrolysate of sugarcane bagasse
Maria Das Graças De Almeida Felipe - One of the best experts on this subject based on the ideXlab platform.
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effect of volumetric oxygen transfer coefficient kla on ethanol production performance by Scheffersomyces Stipitis on hemicellulosic sugarcane bagasse hydrolysate
Biochemical Engineering Journal, 2016Co-Authors: Débora Danielle Virgínio Da Silva, Silvio Silvério Da Silva, Kelly J. Dussán, Valentina Hernandez, Carlos A Cardona, Maria Das Graças De Almeida FelipeAbstract:Abstract Experimental evaluation of the effect of the agitation speed and aeration rate (measured by k L a) and energy required for ethanol production using sugarcane bagasse hemicellulosic hydrolysate (SBHH) by Scheffersomyces Stipitis were studied. Fermentation and purification stages were simulated using the software Aspen Plus with experimental data to understand the overall energy performance of the process. In all experiments, fermentative parameters and the thermal energy required in the ethanol production process were strongly influenced by k L a values. The optimum initial k L a to achieve the maximal ethanol concentration (15.03 g L −1 ) and the minimal thermal energy required (1.85 × 10 5 KW per kg ethanol), were found at 8.0 h −1 (450 rpm and 0.6 vvm). Under this condition, the ethanol yield and productivity were 0.37 g g −1 and 0.30 g L −1 h −1 , respectively. The current study highlights the ethanol production improvement from hemicellulose hydrolysate by S. Stipitis and will contribute to developing a more efficient strategies for fermentation of both cellulose and hemicellulose hydrolysates.
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Effect of volumetric oxygen transfer coefficient (kLa) on ethanol production performance by Scheffersomyces Stipitis on hemicellulosic sugarcane bagasse hydrolysate
Biochemical Engineering Journal, 2016Co-Authors: Débora Danielle Virgínio Da Silva, Silvio Silvério Da Silva, Kelly J. Dussán, Valentina Hernandez, Carlos A Cardona, Maria Das Graças De Almeida FelipeAbstract:Abstract Experimental evaluation of the effect of the agitation speed and aeration rate (measured by k L a) and energy required for ethanol production using sugarcane bagasse hemicellulosic hydrolysate (SBHH) by Scheffersomyces Stipitis were studied. Fermentation and purification stages were simulated using the software Aspen Plus with experimental data to understand the overall energy performance of the process. In all experiments, fermentative parameters and the thermal energy required in the ethanol production process were strongly influenced by k L a values. The optimum initial k L a to achieve the maximal ethanol concentration (15.03 g L −1 ) and the minimal thermal energy required (1.85 × 10 5 KW per kg ethanol), were found at 8.0 h −1 (450 rpm and 0.6 vvm). Under this condition, the ethanol yield and productivity were 0.37 g g −1 and 0.30 g L −1 h −1 , respectively. The current study highlights the ethanol production improvement from hemicellulose hydrolysate by S. Stipitis and will contribute to developing a more efficient strategies for fermentation of both cellulose and hemicellulose hydrolysates.
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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.
Irfan Turhan - One of the best experts on this subject based on the ideXlab platform.
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Ethanol production from different medium compositions of rice husk hydrolysate by using Scheffersomyces Stipitis in a repeated-batch biofilm reactor and its modeling
Process Biochemistry, 2021Co-Authors: Nour Ben Bader, Mustafa Germec, Irfan TurhanAbstract:Abstract This study aimed to generate ethanol from the detoxified/enriched rice husk hydrolysate (RHH) using Scheffersomyces Stipitis in biofilm reactor (BR) and to predict experimental data using models. All fermentation media were supplemented with yeast extract (YE, 1%, w/v), and peptone (PE, 2%, w/v). To construct a plastic composite support-biofilm reactor (PCS-BR), PCS including polypropylene (50 %), soybean hulls (35 %), soybean flours (5%), YE (5%), bovine albumin (5%), and some minerals was selected. Results showed that best carbon source compositions were Medium C (50 % RHH (0.75-L) and 50 % glucose (0.75-L)) and Medium F (75 % RHH (1.125-L) and 25 % xylose (0.375-L). Ethanol yield (YP/S), theoretical YP/S (η), and ethanol concentration were 41.75 and 38.22 %, 81.70 and 74.79 %, and 5.16 and 3.80 g/L in Media C and F, respectively. Regarding the effect of nitrogen sources, the PE (41.75 % YP/S, 81.70 %, and 5.16 g/L) was the best compared to beef extract (40.25 %, 78.77 %, and 4.34 g/L) and NH4NO3 (31.67 %. 61.98 %, and 4.77 g/L). Best models for biomass production in Media C and F were Fitzhugh and Morgan-Mercer-Flodin models, respectively, which also fit-well the experimental ethanol production and substrate consumption data. Consequently, PCS-BR can be used to produce ethanol from RHH for a long-time (57 days).
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Scheffersomyces Stipitis biofilm reactor for ethanol production from acid-pretreated/detoxified and glucose- or xylose-enriched rice husk hydrolysate under a continuous process
Biomass Conversion and Biorefinery, 2020Co-Authors: Nour Ben Bader, Mustafa Germec, Irfan TurhanAbstract:Ethanol is one of the most important platform chemicals that can be produced in a continuous biofilm reactor. The continuous system can be easily adapted to a biofilm reactor, which is a useful tool for ethanol production by microorganisms. In this study, two different media (the first medium : acid-pretreated/detoxified and glucose-enriched rice husk hydrolysate; the second medium : acid-pretreated/detoxified and xylose-enriched rice husk hydrolysate) were used for ethanol production in a continuous biofilm reactor. Both medium (1.5 L) were supplemented with 1% (w/v) yeast extract and 2% (w/v) peptone. The dilution rate for the first medium was between 0.02 and 0.12 h^−1, while for the second medium , it was between 0.01 and 0.05 h^−1. When the first medium was used for ethanol fermentation in a continuous system, maximum ethanol productivity of 0.418 g/L/h and maximum biomass productivity of 0.196 g/L/h were yielded at dilution rates of 0.08 and 0.10 h^−1, respectively. As for the second medium for ethanol fermentation in a continuous system, their values were 0.083 and 0.079 g/L/h at dilution rates of 0.03 and 0.04 h^−1, respectively. Additionally, the yield factors for biomass and ethanol ( Y ^0_ X/S and Y ^0_ P/S ) were also found to be 0.642 g X /g S and 0.49 g P /g S for the first medium and 0.254 g X /g S and 0.27 g P /g S for the second medium , respectively. In addition, although cost-effective ethanol production regarding energy cost and recovery time is desired, the use of the non-enriched sterile and enriched non-sterile media in a repeated-batch biofilm reactor caused low fermentation kinetics. Consequently, ethanol production was successfully performed by using Scheffersomyces Stipitis in a continuous PCS-biofilm reactor including acid-pretreated/detoxified and glucose- or xylose-enriched rice husk hydrolysate, which gave higher ethanol concentration compared with subsequent ethanol fermentation in a repeated-batch biofilm reactor.
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Scheffersomyces Stipitis biofilm reactor for ethanol production from acid pretreated detoxified and glucose or xylose enriched rice husk hydrolysate under a continuous process
Biomass Conversion and Biorefinery, 2020Co-Authors: Nour Ben Bader, Mustafa Germec, Irfan TurhanAbstract:Ethanol is one of the most important platform chemicals that can be produced in a continuous biofilm reactor. The continuous system can be easily adapted to a biofilm reactor, which is a useful tool for ethanol production by microorganisms. In this study, two different media (the first medium: acid-pretreated/detoxified and glucose-enriched rice husk hydrolysate; the second medium: acid-pretreated/detoxified and xylose-enriched rice husk hydrolysate) were used for ethanol production in a continuous biofilm reactor. Both medium (1.5 L) were supplemented with 1% (w/v) yeast extract and 2% (w/v) peptone. The dilution rate for the first medium was between 0.02 and 0.12 h−1, while for the second medium, it was between 0.01 and 0.05 h−1. When the first medium was used for ethanol fermentation in a continuous system, maximum ethanol productivity of 0.418 g/L/h and maximum biomass productivity of 0.196 g/L/h were yielded at dilution rates of 0.08 and 0.10 h−1, respectively. As for the second medium for ethanol fermentation in a continuous system, their values were 0.083 and 0.079 g/L/h at dilution rates of 0.03 and 0.04 h−1, respectively. Additionally, the yield factors for biomass and ethanol (Y0X/S and Y0P/S) were also found to be 0.642 g X/g S and 0.49 g P/g S for the first medium and 0.254 g X/g S and 0.27 g P/g S for the second medium, respectively. In addition, although cost-effective ethanol production regarding energy cost and recovery time is desired, the use of the non-enriched sterile and enriched non-sterile media in a repeated-batch biofilm reactor caused low fermentation kinetics. Consequently, ethanol production was successfully performed by using Scheffersomyces Stipitis in a continuous PCS-biofilm reactor including acid-pretreated/detoxified and glucose- or xylose-enriched rice husk hydrolysate, which gave higher ethanol concentration compared with subsequent ethanol fermentation in a repeated-batch biofilm reactor.
Débora Danielle Virgínio Da Silva - One of the best experts on this subject based on the ideXlab platform.
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effect of volumetric oxygen transfer coefficient kla on ethanol production performance by Scheffersomyces Stipitis on hemicellulosic sugarcane bagasse hydrolysate
Biochemical Engineering Journal, 2016Co-Authors: Débora Danielle Virgínio Da Silva, Silvio Silvério Da Silva, Kelly J. Dussán, Valentina Hernandez, Carlos A Cardona, Maria Das Graças De Almeida FelipeAbstract:Abstract Experimental evaluation of the effect of the agitation speed and aeration rate (measured by k L a) and energy required for ethanol production using sugarcane bagasse hemicellulosic hydrolysate (SBHH) by Scheffersomyces Stipitis were studied. Fermentation and purification stages were simulated using the software Aspen Plus with experimental data to understand the overall energy performance of the process. In all experiments, fermentative parameters and the thermal energy required in the ethanol production process were strongly influenced by k L a values. The optimum initial k L a to achieve the maximal ethanol concentration (15.03 g L −1 ) and the minimal thermal energy required (1.85 × 10 5 KW per kg ethanol), were found at 8.0 h −1 (450 rpm and 0.6 vvm). Under this condition, the ethanol yield and productivity were 0.37 g g −1 and 0.30 g L −1 h −1 , respectively. The current study highlights the ethanol production improvement from hemicellulose hydrolysate by S. Stipitis and will contribute to developing a more efficient strategies for fermentation of both cellulose and hemicellulose hydrolysates.
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Effect of volumetric oxygen transfer coefficient (kLa) on ethanol production performance by Scheffersomyces Stipitis on hemicellulosic sugarcane bagasse hydrolysate
Biochemical Engineering Journal, 2016Co-Authors: Débora Danielle Virgínio Da Silva, Silvio Silvério Da Silva, Kelly J. Dussán, Valentina Hernandez, Carlos A Cardona, Maria Das Graças De Almeida FelipeAbstract:Abstract Experimental evaluation of the effect of the agitation speed and aeration rate (measured by k L a) and energy required for ethanol production using sugarcane bagasse hemicellulosic hydrolysate (SBHH) by Scheffersomyces Stipitis were studied. Fermentation and purification stages were simulated using the software Aspen Plus with experimental data to understand the overall energy performance of the process. In all experiments, fermentative parameters and the thermal energy required in the ethanol production process were strongly influenced by k L a values. The optimum initial k L a to achieve the maximal ethanol concentration (15.03 g L −1 ) and the minimal thermal energy required (1.85 × 10 5 KW per kg ethanol), were found at 8.0 h −1 (450 rpm and 0.6 vvm). Under this condition, the ethanol yield and productivity were 0.37 g g −1 and 0.30 g L −1 h −1 , respectively. The current study highlights the ethanol production improvement from hemicellulose hydrolysate by S. Stipitis and will contribute to developing a more efficient strategies for fermentation of both cellulose and hemicellulose hydrolysates.
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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.
