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Pieternel A M Claassen - One of the best experts on this subject based on the ideXlab platform.
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integration of first and second generation biofuels fermentative hydrogen production from wheat grain and straw
Bioresource Technology, 2013Co-Authors: R R Bakker, Pieternel A M Claassen, I.a. Panagiotopoulos, G J De Vrije, E G KoukiosAbstract:Integrating of lignocellulose-based and starch-rich biomass-based hydrogen production was investigated by mixing wheat straw hydrolysate with a wheat grain hydrolysate for improved fermentation. Enzymatic pretreatment and hydrolysis of wheat grains led to a hydrolysate with a sugar concentration of 93.4 g/L, while dilute-acid pretreatment and enzymatic hydrolysis of wheat straw led to a hydrolysate with sugar concentration 23.0 g/L. Wheat grain hydrolysate was not suitable for hydrogen production by the extreme thermophilic bacterium Caldicellulosiruptor Saccharolyticus at glucose concentrations of 10 g/L or higher, and wheat straw hydrolysate showed good fermentability at total sugar concentrations of up to 10 g/L. The mixed hydrolysates showed good fermentability at the highest tested sugar concentration of 20 g/L, with a hydrogen production of 82–97% of that of the control with pure sugars. Mixing wheat grain hydrolysate with wheat straw hydrolysate would be beneficial for fermentative hydrogen production in a biorefinery.
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dilute acid pretreatment of barley straw for biological hydrogen production using Caldicellulosiruptor Saccharolyticus
International Journal of Hydrogen Energy, 2012Co-Authors: R R Bakker, Pieternel A M Claassen, I.a. Panagiotopoulos, G J De Vrije, E G KoukiosAbstract:Abstract The main objective of this study was to use the fermentability test to investigate the feasibility of applying various dilute acids in the pretreatment of barley straw for biological hydrogen production. At a fixed acid loading of 1% (w/w dry matter) 28–32% of barley straw was converted to soluble monomeric sugars, while at a fixed combined severity of −0.8 30–32% of the straw was converted to soluble monomeric sugars. With fermentability tests at sugar concentrations 10 and 20 g/L the extreme thermophilic bacterium Caldicellulosiruptor Saccharolyticus showed good hydrogen production on hydrolysates of straw pretreated with H3PO4 and H2SO4, and to a lesser extent, HNO3. The fermentability of the hydrolysate of straw pretreated with HCl was lower compared to the other acids but equally high as that of pure sugars. At sugar concentration 30 g/L the fermentability of all hydrolysates was low.
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hydrogen production from carrot pulp by the extreme thermophiles Caldicellulosiruptor Saccharolyticus and thermotoga neapolitana
International Journal of Hydrogen Energy, 2010Co-Authors: Truus De Vrije, Miriam A W Budde, S J J Lips, R R Bakker, Astrid E Mars, Pieternel A M ClaassenAbstract:Abstract Hydrogen was produced from carrot pulp hydrolysate, untreated carrot pulp and (mixtures of) glucose and fructose by the extreme thermophiles Caldicellulosiruptor Saccharolyticus and Thermotoga neapolitana in pH-controlled bioreactors. Carrot pulp hydrolysate was obtained after enzymatic hydrolysis of the polysaccharide fraction in carrot pulp. The main sugars in the hydrolysate were glucose, fructose, and sucrose. In fermentations with glucose hydrogen yields and productivities were similar for both strains. With fructose the hydrogen yield of C. Saccharolyticus was reduced which might be related to uptake of glucose and fructose by different types of transport systems. With T . neapolitana the fructose consumption rate and consequently the hydrogen productivity were low. The hydrogen yields of both thermophiles were 2.7–2.8 mol H 2 /mol hexose with 10 g/L sugars from carrot pulp hydrolysate. With 20 g/L sugars the yield of T. neapolitana was 2.4 mol H 2 /mol hexose while the yield of C. Saccharolyticus was reduced to 1.3 mol H 2 /mol hexose due to high lactate production in the stationary growth phase. C. Saccharolyticus was able to grow on carrot pulp and utilized soluble sugars and, after adaptation, pectin and some (hemi)cellulose. No growth was observed with T. neapolitana when using carrot pulp in agitated fermentations. Enzymatic hydrolysis of the polysaccharide fraction prior to fermentation increased the hydrogen yield with almost 10% to 2.3 g/kg of hydrolyzed carrot pulp.
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potential use of thermophilic dark fermentation effluents in photofermentative hydrogen production by rhodobacter capsulatus
Journal of Cleaner Production, 2010Co-Authors: Ebru Ozgur, Pieternel A M Claassen, G J De Vrije, N Afsar, Meral Yucel, Ufuk Gunduz, Inci ErogluAbstract:Biological hydrogen production by a sequential operation of dark and photofermentation is a promising route to produce hydrogen. The possibility of using renewable resources, like biomass and agro-industrial wastes, provides a dual effect of sustainability in biohydrogen production and simultaneous waste removal. In this study, photofermentative hydrogen production on effluents of thermophilic dark fermentations on glucose, potato steam peels (PSP) hydrolysate and molasses was investigated in indoor, batch operated bioreactors. An extreme thermophile Caldicellulosiruptor Saccharolyticus was used in the dark fermentation step, and Rhodobacter capsulatus (DSM1710) was used in the photofermentation step. Addition of buffer, Fe and Mo to dark fermentor effluents (DFEs) improved the overall efficiency of hydrogen production. The initial acetate concentration in the DFE needed to be adjusted to 30–40 mM by dilution to increase the yield of hydrogen in batch light-supported fermentations. The thermophilic DFEs are suitable for photofermentative hydrogen production, provided that they are supplemented with buffer and nutrients. The overall hydrogen yield of the two-step fermentations was higher than the yield of single step dark fermentations.
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pretreatment of sweet sorghum bagasse for hydrogen production by Caldicellulosiruptor Saccharolyticus
International Journal of Hydrogen Energy, 2010Co-Authors: R R Bakker, I.a. Panagiotopoulos, G J De Vrije, E G Koukios, Pieternel A M ClaassenAbstract:Abstract Pretreatment of sweet sorghum bagasse, an energy crop residue, with NaOH for the production of fermentable substrates, was investigated. Optimal conditions for the alkaline pretreatment of sweet sorghum bagasse were realized at 10% NaOH (w/w dry matter). A delignification of 46% was then observed, and improved significantly the efficiency of enzymatic hydrolysis. Under hydrolysis conditions without pH control, up to 50% and 41% of the cellulose and hemicellulose contained in NaOH-pretreated sweet sorghum bagasse were converted by 24 h enzymatic hydrolysis to soluble monomeric sugars. The extreme thermophilic bacterium Caldicellulosiruptor Saccharolyticus showed normal growth on hydrolysates of NaOH-pretreated biomass up to a sugar concentration of 20 g/L. Besides hydrogen, the main metabolic products detected in the fermentations were acetic and lactic acid. The maximal hydrogen yield observed in batch experiments under controlled conditions was 2.6 mol/mol C6 sugar. The maximal volumetric hydrogen production rate ranged from 10.2 to 10.6 mmol/(L h). At higher substrate concentrations the production of lactic acid increased at the expense of hydrogen production.
Ed W.j. Van Niel - One of the best experts on this subject based on the ideXlab platform.
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a non linear model of hydrogen production by Caldicellulosiruptor Saccharolyticus for diauxic like consumption of lignocellulosic sugar mixtures
Biotechnology for Biofuels, 2018Co-Authors: Johanna Bjorkmalm, Ed W.j. Van Niel, Eoin Byrne, Karin WillquistAbstract:Caldicellulosiruptor Saccharolyticus is an attractive hydrogen producer suitable for growth on various lignocellulosic substrates. The aim of this study was to quantify uptake of pentose and hexose monosaccharides in an industrial substrate and to present a kinetic growth model of C. Saccharolyticus that includes sugar uptake on defined and industrial media. The model is based on Monod and Hill kinetics extended with gas-to-liquid mass transfer and a cybernetic approach to describe diauxic-like growth. Mathematical expressions were developed to describe hydrogen production by C. Saccharolyticus consuming glucose, xylose, and arabinose. The model parameters were calibrated against batch fermentation data. The experimental data included four different cases: glucose, xylose, sugar mixture, and wheat straw hydrolysate (WSH) fermentations. The fermentations were performed without yeast extract. The substrate uptake rate of C. Saccharolyticus on single sugar-defined media was higher on glucose compared to xylose. In contrast, in the defined sugar mixture and WSH, the pentoses were consumed faster than glucose. Subsequently, the cultures entered a lag phase when all pentoses were consumed after which glucose uptake rate increased. This phenomenon suggested a diauxic-like behavior as was deduced from the successive appearance of two peaks in the hydrogen and carbon dioxide productivity. The observation could be described with a modified diauxic model including a second enzyme system with a higher affinity for glucose being expressed when pentose saccharides are consumed. This behavior was more pronounced when WSH was used as substrate. The previously observed co-consumption of glucose and pentoses with a preference for the latter was herein confirmed. However, once all pentoses were consumed, C. Saccharolyticus most probably expressed another uptake system to account for the observed increased glucose uptake rate. This phenomenon could be quantitatively captured in a kinetic model of the entire diauxic-like growth process. Moreover, the observation indicates a regulation system that has fundamental research relevance, since pentose and glucose uptake in C. Saccharolyticus has only been described with ABC transporters, whereas previously reported diauxic growth phenomena have been correlated mainly to PTS systems for sugar uptake.
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evaluation of assimilatory sulphur metabolism in Caldicellulosiruptor Saccharolyticus
Bioresource Technology, 2014Co-Authors: Sudhanshu S Pawar, Ed W.j. Van NielAbstract:Caldicellulosiruptor Saccharolyticus has gained reputation as being among the best microorganisms to produce H2 due to possession of various appropriate features. The quest to develop an inexpensive cultivation medium led to determine a possible replacement of the expensive component cysteine, i.e. sulphate. C. Saccharolyticus assimilated sulphate successfully in absence of a reducing agent without releasing hydrogen sulphide. A complete set of genes coding for enzymes required for sulphate assimilation were found in the majority of Caldicellulosiruptor species including C. Saccharolyticus. C. Saccharolyticus displayed indifferent physiological behaviour to source of sulphur when grown under favourable conditions in continuous cultures. Increasing the usual concentration of sulphur in the feed medium increased substrate conversion. Choice of sulphur source did not affect the tolerance of C. Saccharolyticus to high partial pressures of H2. Thus, sulphate can be a principle sulphur source in an economically viable and more sustainable biohydrogen process using C. Saccharolyticus.
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biohydrogen production from wheat straw hydrolysate using Caldicellulosiruptor Saccharolyticus followed by biogas production in a two step uncoupled process
International Journal of Hydrogen Energy, 2013Co-Authors: Sudhanshu S Pawar, Ahmad A. Zeidan, Valentine Nkongndem Nkemka, Marika Murto, Ed W.j. Van NielAbstract:A two-step, un-coupled process producing hydrogen (H2) from wheat straw using Caldicellulosiruptor Saccharolyticus in a ‘Continuously stirred tank reactor’ (CSTR) followed by anaerobic digestion of its effluent to produce methane (CH4) was investigated. C. Saccharolyticus was able to convert wheat straw hydrolysate to hydrogen at maximum production rate of approximately 5.2 L H2/L/Day. The organic compounds in the effluent collected from the CSTR were successfully converted to CH4 through anaerobic digestion performed in an ‘Up-flow anaerobic sludge bioreactor’ (UASB) reactor at a maximum production rate of 2.6 L CH4/L/day. The maximum energy output of the process (10.9 kJ/g of straw) was about 57% of the total energy, and 67% of the energy contributed by the sugar fraction, contained in the wheat straw. Sparging the hydrogenogenic CSTR with the flue gas of the UASB reactor ((60% v/v) CH4 and (40% v/v) CO2) decreased the H2 production rate by 44%, which was due to the significant presence of CO2. The presence of CH4 alone, like N2, was indifferent to growth and H2 production by C. Saccharolyticus. Hence, sparging with upgraded CH4 would guarantee successful hydrogen production from lignocellulosic biomass prior to anaerobic digestion and thus, reasonably high conversion efficiency can be achieved.
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growth and hydrogen production characteristics of Caldicellulosiruptor Saccharolyticus on chemically defined minimal media
International Journal of Hydrogen Energy, 2012Co-Authors: Karin Willquist, Ed W.j. Van NielAbstract:Caldicellulosiruptor Saccharolyticus is an extreme thermophilic bacterium recognized for its saccharolytic ability and superior ability to produce high yields of hydrogen. However,most studies have been made using yeast extract (YE) as a rich but expensive nutrient source. For the first time, we show that C. Saccharolyticus is able to grow on defined minimal media, including essential vitamins, provided that CO2 was allowed to accumulate sufficiently in the culture broth to activate growth. Growth and hydrogen production performance on minimal media was analyzed in both batch and continuous mode. Absence of YE resulted in similar or higher hydrogen yields and specific hydrogen productivities but lower volumetric hydrogen productivities than with YE. The results also indicate that YE is used as a carbon- and energy source thus affecting metabolic flux calculations. This study clarified that YE is not essential making C. Saccharolyticus more attractive for fundamental studies on its metabolism and future industrial exploitation. (Less)
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reassessment of hydrogen tolerance in Caldicellulosiruptor Saccharolyticus
Microbial Cell Factories, 2011Co-Authors: Karin Willquist, Sudhanshu S Pawar, Ed W.j. Van NielAbstract:Background Caldicellulosiruptor Saccharolyticus has the ability to produce hydrogen (H2) at high yields from a wide spectrum of carbon sources, and has therefore gained industrial interest. For a cost-effective biohydrogen process, the ability of an organism to tolerate high partial pressures of H2 (PH2) is a critical aspect to eliminate the need for continuous stripping of the produced H2 from the bioreactor.
Robert M Kelly - One of the best experts on this subject based on the ideXlab platform.
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Caldicellulosiruptor Saccharolyticus transcriptomes reveal consequences of chemical pretreatment and genetic modification of lignocellulose
Microbial Biotechnology, 2017Co-Authors: Sara E Blumerschuette, Derrick L Lewis, Jeffrey V Zurawski, Jonathan M Conway, Piyum A Khatibi, Vincent L Chiang, Robert M KellyAbstract:Summary Recalcitrance of plant biomass is a major barrier for commercially feasible cellulosic biofuel production. Chemical and enzymatic assays have been developed to measure recalcitrance and carbohydrate composition; however, none of these assays can directly report which polysaccharides a candidate microbe will sense during growth on these substrates. Here, we propose using the transcriptomic response of the plant biomass-deconstructing microbe, Caldicellulosiruptor Saccharolyticus, as a direct measure of how suitable a sample of plant biomass may be for fermentation based on the bioavailability of polysaccharides. Key genes were identified using the global gene response of the microbe to model plant polysaccharides and various types of unpretreated, chemically pretreated and genetically modified plant biomass. While the majority of C. Saccharolyticus genes responding were similar between plant biomasses; subtle differences were discernable, most importantly between chemically pretreated or genetically modified biomass that both exhibit similar levels of solubilization by the microbe. Furthermore, the results here present a new paradigm for assessing plant–microbe interactions that can be deployed as a biological assay to report on the complexity and recalcitrance of plant biomass.
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A thermophile under pressure: Transcriptional analysis of the response of Caldicellulosiruptor Saccharolyticus to different H2 partial pressures
International Journal of Hydrogen Energy, 2013Co-Authors: Abraham Bielen, Amy L Vanfossen, Marcel R A Verhaart, Robert M Kelly, John Van Der Oost, Sara E. Blumer-schuette, Alfons J. M. Stams, Servé KengenAbstract:Abstract Increased hydrogen (H2) levels are known to inhibit H2 formation in Caldicellulosiruptor Saccharolyticus. To investigate this organism's strategy for dealing with elevated H2 levels the effect of the hydrogen partial pressure ( P H 2 ) on fermentation performance was studied by growing cultures under high and low P H 2 in a glucose limited chemostat setup. Transcriptome analysis revealed the upregulation of genes involved in the disposal of reducing equivalents under high P H 2 , like lactate dehydrogenase and alcohol dehydrogenase as well as the NADH-dependent and ferredoxin-dependent hydrogenases. These findings are in line with the observed shift in fermentation profiles from acetate production to the production of acetate, lactate and ethanol under high P H 2 . Moreover, differential transcription was observed for genes involved in carbon metabolism, fatty acid biosynthesis and several transport systems. In addition, presented transcription data provide evidence for the involvement of the redox sensing Rex protein in gene regulation under high P H 2 cultivation conditions.
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s layer homology domain proteins csac_0678 and csac_2722 are implicated in plant polysaccharide deconstruction by the extremely thermophilic bacterium Caldicellulosiruptor Saccharolyticus
Applied and Environmental Microbiology, 2012Co-Authors: Inci Ozdemir, Sara E Blumerschuette, Robert M KellyAbstract:The genus Caldicellulosiruptor contains extremely thermophilic bacteria that grow on plant polysaccharides. The genomes of Caldicellulosiruptor species reveal certain surface layer homology (SLH) domain proteins that have distinguishing features, pointing to a role in lignocellulose deconstruction. Two of these proteins in Caldicellulosiruptor Saccharolyticus (Csac_0678 and Csac_2722) were examined from this perspective. In addition to three contiguous SLH domains, the Csac_0678 gene encodes a glycoside hydrolase family 5 (GH5) catalytic domain and a family 28 carbohydrate-binding module (CBM); orthologs to Csac_0678 could be identified in all genome-sequenced Caldicellulosiruptor species. Recombinant Csac_0678 was optimally active at 75°C and pH 5.0, exhibiting both endoglucanase and xylanase activities. SLH domain removal did not impact Csac_0678 GH activity, but deletion of the CBM28 domain eliminated binding to crystalline cellulose and rendered the enzyme inactive on this substrate. Csac_2722 is the largest open reading frame (ORF) in the C. Saccharolyticus genome (predicted molecular mass of 286,516 kDa) and contains two putative sugar-binding domains, two Big4 domains (bacterial domains with an immunoglobulin [Ig]-like fold), and a cadherin-like (Cd) domain. Recombinant Csac_2722, lacking the SLH and Cd domains, bound to cellulose and had detectable carboxymethylcellulose (CMC) hydrolytic activity. Antibodies directed against Csac_0678 and Csac_2722 confirmed that these proteins bound to the C. Saccharolyticus S-layer. Their cellular localization and functional biochemical properties indicate roles for Csac_0678 and Csac_2722 in recruitment and hydrolysis of complex polysaccharides and the deconstruction of lignocellulosic biomass. Furthermore, these results suggest that related SLH domain proteins in other Caldicellulosiruptor genomes may also be important contributors to plant biomass utilization.
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glycoside hydrolase inventory drives plant polysaccharide deconstruction by the extremely thermophilic bacterium Caldicellulosiruptor Saccharolyticus
Biotechnology and Bioengineering, 2011Co-Authors: Amy L Vanfossen, Inci Ozdemir, Samantha L Zelin, Robert M KellyAbstract:The genome of Caldicellulosiruptor saccharoly- ticus encodes a range of glycoside hydrolases (GHs) that mediate plant biomass deconstruction by this bacterium. Two GH-based genomic loci that appear to be central to the hydrolysis of hemicellulosic and cellulosic substrates were examined. XynB-XynF (Csac_2404-Csac_2411) encodes intracellular and extracellular GHs that are active towards xylan and xylan side-chains, as well as carboxymethyl cellu- lose (CMC). XynD (Csac_2409) and XynE (Csac_2410) were produced recombinantly and confirmed to be xyla- nases. XynF (Csac_2411) was produced in two separate polypeptides, each with one GH43 catalytic domain displaying a-L-arabinofuranosidase activity. CelA-ManB (Csac_1076-Csac_1080) encodes four multi-domain, extra- cellular GHs, including CelB (Csac_1078), a 118 kDa extra- cellular enzyme not present in the other genome-sequenced member of this genus, Caldicellulosiruptor bescii (formerly Anaerocellum thermophilum). CelB contains both GH10 and GH5 domains, separated by a family 3 carbohydrate-binding module (CBM3). CelB encoded in Csac_1078 differed from the version originally reported (Saul et al., 1990, Appl Environ Microbiol 56:3117-3124) with respect to linker regions. CelB hydrolyzed xylan and CMC, as well as barley b-glucan, glucomannan, and arabinoxylan. For all substrates tested, intact CelB was significantly more active than either the individual GH5 and GH10 domains or the two discrete domains together, indicating that the multi-domain archi- tecture is essential for complex carbohydrate hydrolysis. Transcriptomes for C. Saccharolyticus grown at 708 Co n glucose, xylose, xyloglucan, switchgrass, and poplar revealed that certain GHs were particularly responsive to growth on switchgrass and poplar and that CelB was in the top decile of all transcripts during growth on the plant biomass. Biotechnol. Bioeng. 2011;9999: xxx-xxx.
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glycoside hydrolase inventory drives plant polysaccharide deconstruction by the extremely thermophilic bacterium Caldicellulosiruptor Saccharolyticus
Biotechnology and Bioengineering, 2011Co-Authors: Amy L Vanfossen, Inci Ozdemir, Samantha L Zelin, Robert M KellyAbstract:The genome of Caldicellulosiruptor Saccharolyticus encodes a range of glycoside hydrolases (GHs) that mediate plant biomass deconstruction by this bacterium. Two GH-based genomic loci that appear to be central to the hydrolysis of hemicellulosic and cellulosic substrates were examined. XynB-XynF (Csac_2404-Csac_2411) encodes intracellular and extracellular GHs that are active towards xylan and xylan side-chains, as well as carboxymethyl cellulose (CMC). XynD (Csac_2409) and XynE (Csac_2410) were produced recombinantly and confirmed to be xylanases. XynF (Csac_2411) was produced in two separate polypeptides, each with one GH43 catalytic domain displaying α-L-arabinofuranosidase activity. CelA-ManB (Csac_1076-Csac_1080) encodes four multi-domain, extracellular GHs, including CelB (Csac_1078), a 118 kDa extracellular enzyme not present in the other genome-sequenced member of this genus, Caldicellulosiruptor bescii (formerly Anaerocellum thermophilum). CelB contains both GH10 and GH5 domains, separated by a family 3 carbohydrate-binding module (CBM3). CelB encoded in Csac_1078 differed from the version originally reported (Saul et al., 1990, Appl Environ Microbiol 56:3117–3124) with respect to linker regions. CelB hydrolyzed xylan and CMC, as well as barley b-glucan, glucomannan, and arabinoxylan. For all substrates tested, intact CelB was significantly more active than either the individual GH5 and GH10 domains or the two discrete domains together, indicating that the multi-domain architecture is essential for complex carbohydrate hydrolysis. Transcriptomes for C. Saccharolyticus grown at 70°C on glucose, xylose, xyloglucan, switchgrass, and poplar revealed that certain GHs were particularly responsive to growth on switchgrass and poplar and that CelB was in the top decile of all transcripts during growth on the plant biomass.
Yeong-su Kim - One of the best experts on this subject based on the ideXlab platform.
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Borate enhances the production of lactulose from lactose by cellobiose 2-epimerase from Caldicellulosiruptor Saccharolyticus
Bioresource Technology, 2013Co-Authors: Yeong-su Kim, Jung-eun KimAbstract:Abstract Cellobiose 2-epimerase from Caldicellulosiruptor Saccharolyticus was used in the presence of borate to increase the production of lactulose from lactose. Maximum production of lactulose occurred using a 1:1 M ratio of borate–lactose. Under this condition, the enzyme produced 614 g l −1 lactulose from 700 g l −1 lactose after incubation at pH 7.5 and 80 °C for 3 h, with a conversion yield of 88% and a productivity of 205 g l −1 h −1 . The yield and productivity of lactulose production obtained in the present study are among the highest achieved through chemical or biological synthesis.
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lactulose production from lactose as a single substrate by a thermostable cellobiose 2 epimerase from Caldicellulosiruptor Saccharolyticus
Bioresource Technology, 2012Co-Authors: Yeong-su KimAbstract:Abstract The conditions for maximum lactulose production from lactose, as a single substrate, by a thermostable recombinant cellobiose-2-epimerase from Caldicellulosiruptor Saccharolyticus were determined to be pH 7.5, 80 °C, 700 g l −1 lactose, and 150 U ml −1 of enzyme. Under the conditions, the enzyme produced the two bifidus factors lactulose at 408 g l −1 and epilactose at 107 g l −1 after 2 h. The yields of lactulose and epilactose from lactose and the productivities of lactulose and epilactose were 58%, 15%, 204 g l −1 h −1 , and 54 g l −1 h −1 , respectively. The yield and productivity of both lactulose and epilactose from lactose were 74% and 258 g l −1 h −1 , respectively. The yield, concentration, and productivity of lactulose in the present study are the highest among enzymatic syntheses. This is the first trial of enzymatic synthesis of lactulose using the single substrate lactose.
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l-Arabinose production from sugar beet arabinan by immobilized endo- and exo-arabinanases from Caldicellulosiruptor Saccharolyticus in a packed-bed reactor
Journal of bioscience and bioengineering, 2011Co-Authors: Yeong-su Kim, Yu-ri LimAbstract:Abstract The immobilized endo- and exo-arabinanases from Caldicellulosiruptor Saccharolyticus produced continuously an average of 16.5 g l− 1 l -arabinose from 20 g l− 1 sugar beet arabinan at pH 5.0 and 75°C for 216 h, with a productivity of 9.9 g l− 1 h− 1 and a conversion yield of 83%.
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Reduction of galactose inhibition via the mutation of β-galactosidase from Caldicellulosiruptor Saccharolyticus for lactose hydrolysis
Biotechnology Letters, 2011Co-Authors: Yeong-su Kim, Soo-jin YeomAbstract:For the removal of galactose inhibition, the predicted galactose binding residues, which were determined by sequence alignment, were replaced separately with Ala. The activities of the Ala-substituted mutant enzymes were assessed with the addition of galactose. As a consequence, amino acid at position 349 was correlated with the reduction in galactose inhibition. The F349S mutant exhibited the highest activity in the presence of galactose relative to the activity measured in the absence of galactose among the tested mutant enzymes at position 349. The K _i of the F349S mutant (160 mM), which was 13-fold that of the wild-type enzyme, was the highest among the reported values of β -galactosidase. The wild-type enzyme hydrolyzed 62% of 100 g lactose/l with the addition of 30 g galactose/l, whereas the F349S mutant hydrolyzed more than 99%.
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Hydrolytic properties of a thermostable α-l-arabinofuranosidase from Caldicellulosiruptor Saccharolyticus
Journal of applied microbiology, 2010Co-Authors: Yu-ri Lim, Ran-young Yoon, Eun-seon Seo, Yeong-su Kim, Chang-su ParkAbstract:Aims: To characterize of a thermostable recombinant α-L-arabinofuranosidase from Caldicellulosiruptor Saccharolyticus for the hydrolysis of arabino-oligosaccharides to L -arabinose. Methods and Results: A recombinant α-L-arabinofuranosidase from C. Saccharolyticus was purified by heat treatment and Hi-Trap anion exchange chromatography with a specific activity of 28·2 U mg -1 . The native enzyme was a 58-kDa octamer with a molecular mass of 460 kDa, as measured by gel filtration. The catalytic residues and consensus sequences of the glycoside hydrolase 51 family of α-L-arabinofuranosidases were completely conserved in α-L-arabinofuranosidase from C. Saccharolyticus. The maximum enzyme activity was observed at pH 5-5 and 80°C with a half-life of 49 h at 75°C. Among aryl-glycoside substrates, the enzyme displayed activity only for p-nitrophenyl-α-L-arabinofuranoside [maximum k cat /K m of 220 m(mol l -1 ) -1 s -1 ] and p-nitrophenyl-α-L-arabinopyranoside. This substrate specificity differs from those of other α-L-arabinofuranosidases. In a 1 mmol l -1 solution of each sugar, arabino-oligosaccharides with 2-5 monomer units were completely hydrolysed to L -arabinose within 13 h in the presence of 30 U ml -1 of enzyme at 75°C. Conclusions: The novel substrate specificity and hydrolytic properties for arabino-oligosaccharides of α-L-arabinofuranosidase from C. Saccharolyticus demonstrate the potential in the commercial production of L-arabinose in concert with endoarabinanase and/or xylanase. Significance and Impact of the Study: The findings of this work contribute to the knowledge of hydrolytic properties for arabino-oligosaccharides performed by thermostable α-L-arabinofuranosidase.
R R Bakker - One of the best experts on this subject based on the ideXlab platform.
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integration of first and second generation biofuels fermentative hydrogen production from wheat grain and straw
Bioresource Technology, 2013Co-Authors: R R Bakker, Pieternel A M Claassen, I.a. Panagiotopoulos, G J De Vrije, E G KoukiosAbstract:Integrating of lignocellulose-based and starch-rich biomass-based hydrogen production was investigated by mixing wheat straw hydrolysate with a wheat grain hydrolysate for improved fermentation. Enzymatic pretreatment and hydrolysis of wheat grains led to a hydrolysate with a sugar concentration of 93.4 g/L, while dilute-acid pretreatment and enzymatic hydrolysis of wheat straw led to a hydrolysate with sugar concentration 23.0 g/L. Wheat grain hydrolysate was not suitable for hydrogen production by the extreme thermophilic bacterium Caldicellulosiruptor Saccharolyticus at glucose concentrations of 10 g/L or higher, and wheat straw hydrolysate showed good fermentability at total sugar concentrations of up to 10 g/L. The mixed hydrolysates showed good fermentability at the highest tested sugar concentration of 20 g/L, with a hydrogen production of 82–97% of that of the control with pure sugars. Mixing wheat grain hydrolysate with wheat straw hydrolysate would be beneficial for fermentative hydrogen production in a biorefinery.
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dilute acid pretreatment of barley straw for biological hydrogen production using Caldicellulosiruptor Saccharolyticus
International Journal of Hydrogen Energy, 2012Co-Authors: R R Bakker, Pieternel A M Claassen, I.a. Panagiotopoulos, G J De Vrije, E G KoukiosAbstract:Abstract The main objective of this study was to use the fermentability test to investigate the feasibility of applying various dilute acids in the pretreatment of barley straw for biological hydrogen production. At a fixed acid loading of 1% (w/w dry matter) 28–32% of barley straw was converted to soluble monomeric sugars, while at a fixed combined severity of −0.8 30–32% of the straw was converted to soluble monomeric sugars. With fermentability tests at sugar concentrations 10 and 20 g/L the extreme thermophilic bacterium Caldicellulosiruptor Saccharolyticus showed good hydrogen production on hydrolysates of straw pretreated with H3PO4 and H2SO4, and to a lesser extent, HNO3. The fermentability of the hydrolysate of straw pretreated with HCl was lower compared to the other acids but equally high as that of pure sugars. At sugar concentration 30 g/L the fermentability of all hydrolysates was low.
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hydrogen production from carrot pulp by the extreme thermophiles Caldicellulosiruptor Saccharolyticus and thermotoga neapolitana
International Journal of Hydrogen Energy, 2010Co-Authors: Truus De Vrije, Miriam A W Budde, S J J Lips, R R Bakker, Astrid E Mars, Pieternel A M ClaassenAbstract:Abstract Hydrogen was produced from carrot pulp hydrolysate, untreated carrot pulp and (mixtures of) glucose and fructose by the extreme thermophiles Caldicellulosiruptor Saccharolyticus and Thermotoga neapolitana in pH-controlled bioreactors. Carrot pulp hydrolysate was obtained after enzymatic hydrolysis of the polysaccharide fraction in carrot pulp. The main sugars in the hydrolysate were glucose, fructose, and sucrose. In fermentations with glucose hydrogen yields and productivities were similar for both strains. With fructose the hydrogen yield of C. Saccharolyticus was reduced which might be related to uptake of glucose and fructose by different types of transport systems. With T . neapolitana the fructose consumption rate and consequently the hydrogen productivity were low. The hydrogen yields of both thermophiles were 2.7–2.8 mol H 2 /mol hexose with 10 g/L sugars from carrot pulp hydrolysate. With 20 g/L sugars the yield of T. neapolitana was 2.4 mol H 2 /mol hexose while the yield of C. Saccharolyticus was reduced to 1.3 mol H 2 /mol hexose due to high lactate production in the stationary growth phase. C. Saccharolyticus was able to grow on carrot pulp and utilized soluble sugars and, after adaptation, pectin and some (hemi)cellulose. No growth was observed with T. neapolitana when using carrot pulp in agitated fermentations. Enzymatic hydrolysis of the polysaccharide fraction prior to fermentation increased the hydrogen yield with almost 10% to 2.3 g/kg of hydrolyzed carrot pulp.
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pretreatment of sweet sorghum bagasse for hydrogen production by Caldicellulosiruptor Saccharolyticus
International Journal of Hydrogen Energy, 2010Co-Authors: R R Bakker, I.a. Panagiotopoulos, G J De Vrije, E G Koukios, Pieternel A M ClaassenAbstract:Abstract Pretreatment of sweet sorghum bagasse, an energy crop residue, with NaOH for the production of fermentable substrates, was investigated. Optimal conditions for the alkaline pretreatment of sweet sorghum bagasse were realized at 10% NaOH (w/w dry matter). A delignification of 46% was then observed, and improved significantly the efficiency of enzymatic hydrolysis. Under hydrolysis conditions without pH control, up to 50% and 41% of the cellulose and hemicellulose contained in NaOH-pretreated sweet sorghum bagasse were converted by 24 h enzymatic hydrolysis to soluble monomeric sugars. The extreme thermophilic bacterium Caldicellulosiruptor Saccharolyticus showed normal growth on hydrolysates of NaOH-pretreated biomass up to a sugar concentration of 20 g/L. Besides hydrogen, the main metabolic products detected in the fermentations were acetic and lactic acid. The maximal hydrogen yield observed in batch experiments under controlled conditions was 2.6 mol/mol C6 sugar. The maximal volumetric hydrogen production rate ranged from 10.2 to 10.6 mmol/(L h). At higher substrate concentrations the production of lactic acid increased at the expense of hydrogen production.
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biohydrogen production from untreated and hydrolyzed potato steam peels by the extreme thermophiles Caldicellulosiruptor Saccharolyticus and thermotoga neapolitana
International Journal of Hydrogen Energy, 2010Co-Authors: Astrid E Mars, Truus De Vrije, Miriam A W Budde, S J J Lips, R R Bakker, Teun Veuskens, Patrick F N M Van Doeveren, Pieternel A M ClaassenAbstract:Abstract Production of hydrogen by the extreme thermophiles Caldicellulosiruptor Saccharolyticus and Thermotoga neapolitana was studied in serum flasks and in pH-controlled bioreactors with glucose, and hydrolyzed and untreated potato steam peels (PSP) as carbon sources. Two types of PSP hydrolysates were used: one in which the starch in the PSP was liquefied with alpha-amylase, and one in which the liquefied starch was further hydrolyzed to glucose by amyloglucosidase. When the PSP hydrolysates or untreated PSP were added at circa 10–14 g/L of glucose units, both strains grew well and produced hydrogen with reasonable to high molar yields (2.4–3.8 moles H 2 /mole glucose units), and no significant production of lactate. The hydrogen production rates and yields were similar with untreated PSP, hydrolyzed PSP, and pure glucose, showing that C. Saccharolyticus and T. neapolitana are well equipped for the utilization of starch. When the concentrations of the substrates were increased, growth and hydrogen production of both strains were hampered. At substrate concentrations of circa 30–40 g/L of glucose units, the molar hydrogen yield of C. Saccharolyticus was severely reduced due to the formation of high amounts of lactate, while T. neapolitana was unable to grow at all. The results showed that PSP and PSP hydrolysates are very suitable substrates for efficient fermentative hydrogen production at moderate substrate loadings.
