51
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Liu Y, Zhang B, Wang W, He M, Xu J, Yuan Z. Evaluation of the solvent water effect on high solids saccharification of alkali-pretreated sugarcane bagasse. BIORESOURCE TECHNOLOGY 2017; 235:12-17. [PMID: 28351727 DOI: 10.1016/j.biortech.2017.03.088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 03/13/2017] [Accepted: 03/14/2017] [Indexed: 06/06/2023]
Abstract
Solvent water is an essential factor for high solids enzymatic hydrolysis. To investigate its effect on substrate conversion efficiency in high solids hydrolysis of sugarcane bagasse (SCB), oleyl alcohol was used to partially substitute the solvent water. The results in batch hydrolysis tests in which diverse ratio of solvent water was replaced found that the majority of the substrate was insoluble. Then high solids fed-batch hydrolysis with the reaction solution mixed with solvent water and oleyl alcohol in the ratio of 3:1 (solids concentration correspond to 24% (w/v)) was carried out at the final real solids loading of 18% (w/v). The produced sugars were found to be less than pure water system, which indicated that water played a significant role in high solids hydrolysis process, and solids effect was related to the solvent water content.
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Affiliation(s)
- Yunyun Liu
- College of Mechanical and Electrical Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China; Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Bin Zhang
- College of Mechanical and Electrical Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China
| | - Wen Wang
- Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Minchao He
- Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Jingliang Xu
- Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China
| | - Zhenhong Yuan
- Key Laboratory of Renewable Energy, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China.
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52
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Gama R, Van Dyk JS, Burton MH, Pletschke BI. Using an artificial neural network to predict the optimal conditions for enzymatic hydrolysis of apple pomace. 3 Biotech 2017; 7:138. [PMID: 28593522 DOI: 10.1007/s13205-017-0754-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 01/23/2017] [Indexed: 10/19/2022] Open
Abstract
The enzymatic degradation of lignocellulosic biomass such as apple pomace is a complex process influenced by a number of hydrolysis conditions. Predicting optimal conditions, including enzyme and substrate concentration, temperature and pH can improve conversion efficiency. In this study, the production of sugar monomers from apple pomace using commercial enzyme preparations, Celluclast 1.5L, Viscozyme L and Novozyme 188 was investigated. A limited number of experiments were carried out and then analysed using an artificial neural network (ANN) to model the enzymatic hydrolysis process. The ANN was used to simulate the enzymatic hydrolysis process for a range of input variables and the optimal conditions were successfully selected as was indicated by the R 2 value of 0.99 and a small MSE value. The inputs for the ANN were substrate loading, enzyme loading, temperature, initial pH and a combination of these parameters, while release profiles of glucose and reducing sugars were the outputs. Enzyme loadings of 0.5 and 0.2 mg/g substrate and a substrate loading of 30% were optimal for glucose and reducing sugar release from apple pomace, respectively, resulting in concentrations of 6.5 g/L glucose and 28.9 g/L reducing sugars. Apple pomace hydrolysis can be successfully carried out based on the predicted optimal conditions from the ANN.
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53
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Liu Y, Guo L, Wang L, Zhan W, Zhou H. Irradiation pretreatment facilitates the achievement of high total sugars concentration from lignocellulose biomass. BIORESOURCE TECHNOLOGY 2017; 232:270-277. [PMID: 28237898 DOI: 10.1016/j.biortech.2017.01.061] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/26/2017] [Accepted: 01/27/2017] [Indexed: 05/25/2023]
Abstract
This study evaluated the two hydrolysis strategies, involving one thermal and one dilute acid/enzymatic hydrolysis, to produce high xylose and glucose concentrations from lignocellulose assisted with irradiation pretreatment. Prior to hydrolysis, lignocellulose was pretreated by γ-irradiation at 800KGy. The merits of irradiation pretreatment on lignocellulose were contributed to size-reduced particle distributions and low shear rate of material, which allowed high biomass loadings up to 30-40%(w/v, equals to 23-29wt.%) for the consequent hydrolysis process. Results showed that hemicellulose fraction could achieve ∼84g/L of total sugars containing ∼55g/L xylose and ∼21g/L glucose through this two steps hydrolysis. Cellulose fraction would release ∼251g/L of total sugars consisting of ∼235g/L glucose and ∼16g/L xylose in the ultimate enzymatic hydrolysate. To the best of our knowledge, it was the first report of achieving 235g/L glucose in cellulose enzymatic hydrolysate derived from lignocellulose.
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Affiliation(s)
- Yun Liu
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Lijun Guo
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Liuyang Wang
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Wang Zhan
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Hua Zhou
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
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54
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Du J, Cao Y, Liu G, Zhao J, Li X, Qu Y. Identifying and overcoming the effect of mass transfer limitation on decreased yield in enzymatic hydrolysis of lignocellulose at high solid concentrations. BIORESOURCE TECHNOLOGY 2017; 229:88-95. [PMID: 28110129 DOI: 10.1016/j.biortech.2017.01.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 01/06/2017] [Accepted: 01/07/2017] [Indexed: 05/18/2023]
Abstract
Cellulose conversion decreases significantly with increasing solid concentrations during enzymatic hydrolysis of insoluble lignocellulosic materials. Here, mass transfer limitation was identified as a significant determining factor of this decrease by studying the hydrolysis of delignified corncob residue in shake flask, the most used reaction vessel in bench scale. Two mass transfer efficiency-related factors, mixing speed and flask filling, were shown to correlate closely with cellulose conversion at solid loadings higher than 15% DM. The role of substrate characteristics in mass transfer performance was also significant, which was revealed by the saccharification of two corn stover substrates with different pretreatment methods at the same solid loading. Several approaches including premix, fed-batch operation, and particularly the use of horizontal rotating reactor were shown to be valid in facilitating cellulose conversion via improving mass transfer efficiency at solid concentrations higher than 15% DM.
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Affiliation(s)
- Jian Du
- State Key Laboratory of Microbial Technology, Shandong University, 250100, China
| | - Yuan Cao
- State Key Laboratory of Microbial Technology, Shandong University, 250100, China
| | - Guodong Liu
- State Key Laboratory of Microbial Technology, Shandong University, 250100, China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, 250100, China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, 250100, China
| | - Yinbo Qu
- State Key Laboratory of Microbial Technology, Shandong University, 250100, China; National Glycoengineering Research Center, Shandong University, 250100, China.
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55
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Simultaneous saccharification and fermentation of alkali-pretreated corncob under optimized conditions using cold-tolerant indigenous holocellulase. KOREAN J CHEM ENG 2017. [DOI: 10.1007/s11814-016-0334-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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56
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Fed-Batch Enzymatic Saccharification of High Solids Pretreated Lignocellulose for Obtaining High Titers and High Yields of Glucose. Appl Biochem Biotechnol 2017; 182:1108-1120. [DOI: 10.1007/s12010-016-2385-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 12/27/2016] [Indexed: 10/20/2022]
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57
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Westman JO, Wang R, Novy V, Franzén CJ. Sustaining fermentation in high-gravity ethanol production by feeding yeast to a temperature-profiled multifeed simultaneous saccharification and co-fermentation of wheat straw. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:213. [PMID: 28919926 PMCID: PMC5596858 DOI: 10.1186/s13068-017-0893-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 08/24/2017] [Indexed: 05/17/2023]
Abstract
BACKGROUND Considerable progress is being made in ethanol production from lignocellulosic feedstocks by fermentation, but negative effects of inhibitors on fermenting microorganisms are still challenging. Feeding preadapted cells has shown positive effects by sustaining fermentation in high-gravity simultaneous saccharification and co-fermentation (SSCF). Loss of cell viability has been reported in several SSCF studies on different substrates and seems to be the main reason for the declining ethanol production toward the end of the process. Here, we investigate how the combination of yeast preadaptation and feeding, cell flocculation, and temperature reduction improves the cell viability in SSCF of steam pretreated wheat straw. RESULTS More than 50% cell viability was lost during the first 24 h of high-gravity SSCF. No beneficial effects of adding selected nutrients were observed in shake flask SSCF. Ethanol concentrations greater than 50 g L-1 led to significant loss of viability and prevented further fermentation in SSCF. The benefits of feeding preadapted yeast cells were marginal at later stages of SSCF. Yeast flocculation did not improve the viability but simplified cell harvest and improved the feasibility of the cell feeding strategy in demo scale. Cultivation at 30 °C instead of 35 °C increased cell survival significantly on solid media containing ethanol and inhibitors. Similarly, in multifeed SSCF, cells maintained the viability and fermentation capacity when the temperature was reduced from 35 to 30 °C during the process, but hydrolysis yields were compromised. By combining the yeast feeding and temperature change, an ethanol concentration of 65 g L-1, equivalent to 70% of the theoretical yield, was obtained in multifeed SSCF on pretreated wheat straw. In demo scale, the process with flocculating yeast and temperature profile resulted in 5% (w/w) ethanol, equivalent to 53% of the theoretical yield. CONCLUSIONS Multifeed SSCF was further developed by means of a flocculating yeast and a temperature-reduction profile. Ethanol toxicity is intensified in the presence of lignocellulosic inhibitors at temperatures that are beneficial to hydrolysis in high-gravity SSCF. The counteracting effects of temperature on cell viability and hydrolysis call for more tolerant microorganisms, enzyme systems with lower temperature optimum, or full optimization of the multifeed strategy with temperature profile.
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Affiliation(s)
- Johan O. Westman
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Present Address: Chr. Hansen A/S, Bøge Allé 10-12, 2970 Hørsholm, Denmark
| | - Ruifei Wang
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Vera Novy
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, Graz, Austria
- Present Address: Forest Products Biotechnology, Faculty of Forestry, University of British Columbia, Vancouver, BC V6T1Z4 Canada
| | - Carl Johan Franzén
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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58
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Chen HZ, Liu ZH. Enzymatic hydrolysis of lignocellulosic biomass from low to high solids loading. Eng Life Sci 2016; 17:489-499. [PMID: 32624794 DOI: 10.1002/elsc.201600102] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 09/24/2016] [Accepted: 10/20/2016] [Indexed: 02/01/2023] Open
Abstract
Solid state enzymatic hydrolysis (SSEH) has many advantages, such as higher sugar concentration, lower operating costs, and less energy input. It should be a potential approach for the industrial application of lignocellulosic ethanol. The purpose of this work is to review the enzymatic hydrolysis of lignocellulosic biomass from low to high solids loading and introduce its both challenges and perspectives. The limitations of SSEH, including inhibition effects, water constraint, and rheology characteristic, are summarized firstly. Various strategies for overcoming these limitations are proposed correspondingly. Fed batch process and its feeding strategy to improve the SSEH efficiency are then discussed. Finally, several intensification methods, hydrolysis reactor, and pilot- and demonstration-scale operations of SSEH are described. In-depth analysis of main limitations and development of novel intensification methods and reactors should provide an effective way to achieve large-scale implementation of SSEH.
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Affiliation(s)
- Hong-Zhang Chen
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering Chinese Academy of Sciences Beijing China
| | - Zhi-Hua Liu
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering Chinese Academy of Sciences Beijing China.,University of Chinese Academy of Sciences Beijing China
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59
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Optimal control of enzymatic hydrolysis of lignocellulosic biomass. RESOURCE-EFFICIENT TECHNOLOGIES 2016. [DOI: 10.1016/j.reffit.2016.11.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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60
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Bondesson PM, Galbe M. Process design of SSCF for ethanol production from steam-pretreated, acetic-acid-impregnated wheat straw. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:222. [PMID: 27777624 PMCID: PMC5070003 DOI: 10.1186/s13068-016-0635-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 10/07/2016] [Indexed: 05/05/2023]
Abstract
BACKGROUND Pretreatment is an important step in the production of ethanol from lignocellulosic material. Using acetic acid together with steam pretreatment allows the positive effects of an acid catalyst to be retained, while avoiding the negative environmental effects associated with sulphuric acid. Acetic acid is also formed during the pretreatment and hydrolysis of hemicellulose, and is a known inhibitor that may impair fermentation at high concentrations. The purpose of this study was to improve ethanol production from glucose and xylose in steam-pretreated, acetic-acid-impregnated wheat straw by process design of simultaneous saccharification and co-fermentation (SSCF), using a genetically modified pentose fermenting yeast strain Saccharomyces cerevisiae. RESULTS Ethanol was produced from glucose and xylose using both the liquid fraction and the whole slurry from pretreated materials. The highest ethanol concentration achieved was 37.5 g/L, corresponding to an overall ethanol yield of 0.32 g/g based on the glucose and xylose available in the pretreated material. To obtain this concentration, a slurry with a water-insoluble solids (WIS) content of 11.7 % was used, using a fed-batch SSCF strategy. A higher overall ethanol yield (0.36 g/g) was obtained at 10 % WIS. CONCLUSIONS Ethanol production from steam-pretreated, acetic-acid-impregnated wheat straw through SSCF with a pentose fermenting S. cerevisiae strain was successfully demonstrated. However, the ethanol concentration was too low and the residence time too long to be suitable for large-scale applications. It is hoped that further process design focusing on the enzymatic conversion of cellulose to glucose will allow the combination of acetic acid pretreatment and co-fermentation of glucose and xylose.
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Affiliation(s)
- Pia-Maria Bondesson
- Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00 Lund, Sweden
| | - Mats Galbe
- Department of Chemical Engineering, Lund University, P.O. Box 124, 221 00 Lund, Sweden
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61
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Colabardini AC, Valkonen M, Huuskonen A, Siika-aho M, Koivula A, Goldman GH, Saloheimo M. Expression of Two Novel β-Glucosidases from Chaetomium atrobrunneum in Trichoderma reesei and Characterization of the Heterologous Protein Products. Mol Biotechnol 2016; 58:821-831. [DOI: 10.1007/s12033-016-9981-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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62
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Sant’Ana da Silva A, Fernandes de Souza M, Ballesteros I, Manzanares P, Ballesteros M, P. S. Bon E. High-solids content enzymatic hydrolysis of hydrothermally pretreated sugarcane bagasse using a laboratory-made enzyme blend and commercial preparations. Process Biochem 2016. [DOI: 10.1016/j.procbio.2016.07.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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63
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Sugiharto YEC, Harimawan A, Kresnowati MTAP, Purwadi R, Mariyana R, Fitriana HN, Hosen HF. Enzyme feeding strategies for better fed-batch enzymatic hydrolysis of empty fruit bunch. BIORESOURCE TECHNOLOGY 2016; 207:175-9. [PMID: 26881335 DOI: 10.1016/j.biortech.2016.01.113] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 01/28/2016] [Accepted: 01/29/2016] [Indexed: 05/15/2023]
Abstract
Lignin inhibitory becomes a major obstacle for enzymatic hydrolysis of empty fruit bunch conducted in high solid loading. Since current technology required high enzyme loading, surfactant application could not effectively used since it is only efficient in low enzyme loading. In addition, it will increase final operation cost. Hence, another method namely "proportional enzyme feeding" was investigated in this paper. In this method, enzyme was added to reactor proportionally to substrate addition, different from conventional method ("whole enzyme feeding") where whole enzyme was added prior to hydrolysis process started. Proportional enzyme feeding could increase enzymatic digestibility and glucose concentration up to 26% and 12% respectively, compared to whole enzyme feeding for hydrolysis duration more than 40h. If enzymatic hydrolysis was run less than 40h (25% solid loading), whole enzyme feeding is preferable.
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Affiliation(s)
| | - Ardiyan Harimawan
- Department of Chemical Engineering, Faculty of Industrial Technology, Institut Teknologi Bandung, Ganesha 10, Bandung 40132, Indonesia
| | - Made Tri Ari Penia Kresnowati
- Department of Chemical Engineering, Faculty of Industrial Technology, Institut Teknologi Bandung, Ganesha 10, Bandung 40132, Indonesia
| | - Ronny Purwadi
- Department of Chemical Engineering, Faculty of Industrial Technology, Institut Teknologi Bandung, Ganesha 10, Bandung 40132, Indonesia
| | - Rina Mariyana
- PT Rekayasa Industri, Kalibata Timur 1 Street 36 Kalibata, Jakarta 12740, Indonesia
| | - Hana Nur Fitriana
- Department of Chemical Engineering, Faculty of Industrial Technology, Institut Teknologi Bandung, Ganesha 10, Bandung 40132, Indonesia
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64
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Cui C, Qian Y, Sun W, Zhao H. Effects of high solid concentrations on the efficacy of enzymatic hydrolysis of yeast cells and the taste characteristics of the resulting hydrolysates. Int J Food Sci Technol 2016; 51:1298-1304. [DOI: 10.1111/ijfs.13084] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 01/28/2016] [Indexed: 07/02/2024]
Abstract
SummaryEffects of solid concentrations on enzymatic hydrolysis of yeast cells and the taste characteristics of the resulting hydrolysates were examined. Results showed that increased solid concentrations ranging from 10% to 30% resulted in a mild increase in degree of hydrolysis (DH) of hydrolysates during the whole hydrolysis process, whereas an obvious inhibition effect on DH was found at hydrolysates with 40% of solid concentration. The levels of amino nitrogen and total nitrogen of supernatant with 40% of solid concentration were six‐fold higher than those of hydrolysates with 10% of solid concentration at all hydrolysis time. After 21 h of hydrolysis, there was no significant difference in molecular weight distributions of hydrolysates with different solid concentrations, while a significant increase in amino acid contents of hydrolysates with high solid concentrations was found. Results from sensory evaluation showed that the intensities of umami, mouthfulness and continuity in umami solution could be significantly improved by supplementing with the resulting hydrolysates with high solid concentrations.
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Affiliation(s)
- Chun Cui
- School of Food Science and Technology South China University of Technology Guangzhou 510640 China
| | - Yangpeng Qian
- School of Food Science and Technology South China University of Technology Guangzhou 510640 China
| | - Weizheng Sun
- School of Food Science and Technology South China University of Technology Guangzhou 510640 China
| | - Haifeng Zhao
- School of Food Science and Technology South China University of Technology Guangzhou 510640 China
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65
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Schell DJ, Dowe N, Chapeaux A, Nelson RS, Jennings EW. Accounting for all sugars produced during integrated production of ethanol from lignocellulosic biomass. BIORESOURCE TECHNOLOGY 2016; 205:153-158. [PMID: 26826954 DOI: 10.1016/j.biortech.2016.01.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 01/05/2016] [Accepted: 01/06/2016] [Indexed: 06/05/2023]
Abstract
Accurate mass balance and conversion data from integrated operation is needed to fully elucidate the economics of biofuel production processes. This study explored integrated conversion of corn stover to ethanol and highlights techniques for accurate yield calculations. Acid pretreated corn stover (PCS) produced in a pilot-scale reactor was enzymatically hydrolyzed and the resulting sugars were fermented to ethanol by the glucose-xylose fermenting bacteria, Zymomonas mobilis 8b. The calculations presented here account for high solids operation and oligomeric sugars produced during pretreatment, enzymatic hydrolysis, and fermentation, which, if not accounted for, leads to overestimating ethanol yields. The calculations are illustrated for enzymatic hydrolysis and fermentation of PCS at 17.5% and 20.0% total solids achieving 80.1% and 77.9% conversion of cellulose and xylan to ethanol and ethanol titers of 63g/L and 69g/L, respectively. These procedures will be employed in the future and the resulting information used for techno-economic analysis.
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Affiliation(s)
- Daniel J Schell
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA.
| | - Nancy Dowe
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | | | - Robert S Nelson
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
| | - Edward W Jennings
- National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401, USA
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66
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Tai C, Voltan DS, Keshwani DR, Meyer GE, Kuhar PS. Fuzzy logic feedback control for fed-batch enzymatic hydrolysis of lignocellulosic biomass. Bioprocess Biosyst Eng 2016; 39:937-44. [PMID: 26915095 DOI: 10.1007/s00449-016-1573-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 02/15/2016] [Indexed: 11/28/2022]
Abstract
A fuzzy logic feedback control system was developed for process monitoring and feeding control in fed-batch enzymatic hydrolysis of a lignocellulosic biomass, dilute acid-pretreated corn stover. Digested glucose from hydrolysis reaction was assigned as input while doser feeding time and speed of pretreated biomass were responses from fuzzy logic control system. Membership functions for these three variables and rule-base were created based on batch hydrolysis data. The system response was first tested in LabVIEW environment then the performance was evaluated through real-time hydrolysis reaction. The feeding operations were determined timely by fuzzy logic control system and efficient responses were shown to plateau phases during hydrolysis. Feeding of proper amount of cellulose and maintaining solids content was well balanced. Fuzzy logic proved to be a robust and effective online feeding control tool for fed-batch enzymatic hydrolysis.
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Affiliation(s)
- Chao Tai
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Diego S Voltan
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA.,Rural Engineering Department, College of Agricultural Sciences, São Paulo State University, Botucatu, SP, 18610-307, Brazil
| | - Deepak R Keshwani
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA.
| | - George E Meyer
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
| | - Pankaj S Kuhar
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, 68583, USA
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67
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Corrêa LJ, Badino AC, Cruz AJG. Power consumption evaluation of different fed-batch strategies for enzymatic hydrolysis of sugarcane bagasse. Bioprocess Biosyst Eng 2016; 39:825-33. [DOI: 10.1007/s00449-016-1562-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/02/2016] [Indexed: 10/22/2022]
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68
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Unrean P. Bioprocess modelling for the design and optimization of lignocellulosic biomass fermentation. BIORESOUR BIOPROCESS 2016. [DOI: 10.1186/s40643-015-0079-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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69
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Wang R, Unrean P, Franzén CJ. Model-based optimization and scale-up of multi-feed simultaneous saccharification and co-fermentation of steam pre-treated lignocellulose enables high gravity ethanol production. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:88. [PMID: 27096006 PMCID: PMC4835939 DOI: 10.1186/s13068-016-0500-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 04/01/2016] [Indexed: 05/15/2023]
Abstract
BACKGROUND High content of water-insoluble solids (WIS) is required for simultaneous saccharification and co-fermentation (SSCF) operations to reach the high ethanol concentrations that meet the techno-economic requirements of industrial-scale production. The fundamental challenges of such processes are related to the high viscosity and inhibitor contents of the medium. Poor mass transfer and inhibition of the yeast lead to decreased ethanol yield, titre and productivity. In the present work, high-solid SSCF of pre-treated wheat straw was carried out by multi-feed SSCF which is a fed-batch process with additions of substrate, enzymes and cells, integrated with yeast propagation and adaptation on the pre-treatment liquor. The combined feeding strategies were systematically compared and optimized using experiments and simulations. RESULTS For high-solid SSCF process of SO2-catalyzed steam pre-treated wheat straw, the boosted solubilisation of WIS achieved by having all enzyme loaded at the beginning of the process is crucial for increased rates of both enzymatic hydrolysis and SSCF. A kinetic model was adapted to simulate the release of sugars during separate hydrolysis as well as during SSCF. Feeding of solid substrate to reach the instantaneous WIS content of 13 % (w/w) was carried out when 60 % of the cellulose was hydrolysed, according to simulation results. With this approach, accumulated WIS additions reached more than 20 % (w/w) without encountering mixing problems in a standard bioreactor. Feeding fresh cells to the SSCF reactor maintained the fermentation activity, which otherwise ceased when the ethanol concentration reached 40-45 g L(-1). In lab scale, the optimized multi-feed SSCF produced 57 g L(-1) ethanol in 72 h. The process was reproducible and resulted in 52 g L(-1) ethanol in 10 m(3) scale at the SP Biorefinery Demo Plant. CONCLUSIONS SSCF of WIS content up to 22 % (w/w) is reproducible and scalable with the multi-feed SSCF configuration and model-aided process design. For simultaneous saccharification and fermentation, the overall efficiency relies on balanced rates of substrate feeding and conversion. Multi-feed SSCF provides the possibilities to balance interdependent rates by systematic optimization of the feeding strategies. The optimization routine presented in this work can easily be adapted for optimization of other lignocellulose-based fermentation systems.
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Affiliation(s)
- Ruifei Wang
- />Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Pornkamol Unrean
- />Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
- />National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathum Thani, Thailand
| | - Carl Johan Franzén
- />Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
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70
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Principles and Challenges Involved in the Enzymatic Hydrolysis of Cellulosic Materials at High Total Solids. GREEN FUELS TECHNOLOGY 2016. [DOI: 10.1007/978-3-319-30205-8_7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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71
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Quiroga AG, Silvera AB, Padilla RV, Costa ACD, Maciel Filho R. CONTINUOUS AND SEMICONTINUOUS REACTION SYSTEMS FOR HIGH-SOLIDS ENZYMATIC HYDROLYSIS OF LIGNOCELLULOSICS. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2015. [DOI: 10.1590/0104-6632.20150324s00003547] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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72
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Cardona MJ, Tozzi EJ, Karuna N, Jeoh T, Powell RL, McCarthy MJ. A process for energy-efficient high-solids fed-batch enzymatic liquefaction of cellulosic biomass. BIORESOURCE TECHNOLOGY 2015; 198:488-496. [PMID: 26432053 DOI: 10.1016/j.biortech.2015.09.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2015] [Revised: 09/04/2015] [Accepted: 09/05/2015] [Indexed: 06/05/2023]
Abstract
The enzymatic hydrolysis of cellulosic biomass is a key step in the biochemical production of fuels and chemicals. Economically feasible large-scale implementation of the process requires operation at high solids loadings, i.e., biomass concentrations >15% (w/w). At increasing solids loadings, however, biomass forms a high viscosity slurry that becomes increasingly challenging to mix and severely mass transfer limited, which limits further addition of solids. To overcome these limitations, we developed a fed-batch process controlled by the yield stress and its changes during liquefaction of the reaction mixture. The process control relies on an in-line, non-invasive magnetic resonance imaging (MRI) rheometer to monitor real-time evolution of yield stress during liquefaction. Additionally, we demonstrate that timing of enzyme addition relative to biomass addition influences process efficiency, and the upper limit of solids loading is ultimately limited by end-product inhibition as soluble glucose and cellobiose accumulate in the liquid phase.
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Affiliation(s)
- M J Cardona
- Department of Chemical Engineering and Materials Science, University of California, Davis, One Shields Ave, Davis, CA 95616, USA
| | - E J Tozzi
- Aspect Imaging, One Shields Ave, Davis, CA 95616, USA
| | - N Karuna
- Department of Biological and Agricultural Engineering, University of California, Davis, One Shields Ave, Davis, CA 95616, USA
| | - T Jeoh
- Department of Biological and Agricultural Engineering, University of California, Davis, One Shields Ave, Davis, CA 95616, USA.
| | - R L Powell
- Department of Chemical Engineering and Materials Science, University of California, Davis, One Shields Ave, Davis, CA 95616, USA; Department of Food Science and Technology, University of California, Davis, One Shields Ave, Davis, CA 95616, USA
| | - M J McCarthy
- Department of Biological and Agricultural Engineering, University of California, Davis, One Shields Ave, Davis, CA 95616, USA; Department of Food Science and Technology, University of California, Davis, One Shields Ave, Davis, CA 95616, USA
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73
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Angarita J, Souza R, Cruz A, Biscaia E, Secchi A. Kinetic modeling for enzymatic hydrolysis of pretreated sugarcane straw. Biochem Eng J 2015. [DOI: 10.1016/j.bej.2015.05.021] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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74
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Gaona A, Lawryshyn Y, Saville B. The Effect of Fed-Batch Operation and Rotational Speed on High-Solids Enzymatic Hydrolysis of Hardwood Substrates. Ind Biotechnol (New Rochelle N Y) 2015. [DOI: 10.1089/ind.2014.0031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Adriana Gaona
- Laboratory of Bioprocess and Enzyme Technology, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | - Yuri Lawryshyn
- Laboratory of Bioprocess and Enzyme Technology, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | - Bradley Saville
- Laboratory of Bioprocess and Enzyme Technology, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
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75
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Optimization of high solids fed-batch saccharification of sugarcane bagasse based on system viscosity changes. J Biotechnol 2015; 211:5-9. [DOI: 10.1016/j.jbiotec.2015.06.422] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Revised: 06/12/2015] [Accepted: 06/26/2015] [Indexed: 11/23/2022]
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76
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Vani S, Sukumaran RK, Savithri S. Prediction of sugar yields during hydrolysis of lignocellulosic biomass using artificial neural network modeling. BIORESOURCE TECHNOLOGY 2015; 188:128-135. [PMID: 25739999 DOI: 10.1016/j.biortech.2015.01.083] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 01/16/2015] [Accepted: 01/18/2015] [Indexed: 06/04/2023]
Abstract
The present investigation was carried out to study application of ANN as a tool for predicting sugar yields of pretreated biomass during hydrolysis process at various time intervals. Since it is known that biomass loading and particle size influences the rheology and mass transfer during hydrolysis process, these two parameters were chosen for investigating the efficiency of hydrolysis. Alkali pretreated rice straw was used as the model feedstock in this study and biomass loadings were varied from 10% to 18%. Substrate particle sizes used were <0.5mm, 0.5-1mm, >1mm and mixed size. Effectiveness of hydrolysis was strongly influenced by biomass loadings, whereas particle size did not have any significant impact on sugar yield. Higher biomass loadings resulted in higher sugar concentration in the hydrolysates. Optimum hydrolysis conditions predicted were 10 FPU/g cellulase, 5 IU/g BGL, 7500 U/g xylanase, 18% biomass loading and mixed particle size with reaction time between 12-28 h.
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Affiliation(s)
- Sankar Vani
- Centre for Biofuels, Biotechnology Division, CSIR - National Institute for Interdisciplinary Science and Technology, Industrial Estate PO, Trivandrum 695019, India
| | - Rajeev Kumar Sukumaran
- Centre for Biofuels, Biotechnology Division, CSIR - National Institute for Interdisciplinary Science and Technology, Industrial Estate PO, Trivandrum 695019, India
| | - Sivaraman Savithri
- Computational Modeling and Simulation Section, Process Engineering & Environmental Technology Division, CSIR - National Institute for Interdisciplinary Science and Technology, Industrial Estate PO, Trivandrum 695019, India.
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77
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Scott F, Li M, Williams DL, Conejeros R, Hodge DB, Aroca G. Corn stover semi-mechanistic enzymatic hydrolysis model with tight parameter confidence intervals for model-based process design and optimization. BIORESOURCE TECHNOLOGY 2015; 177:255-265. [PMID: 25496946 DOI: 10.1016/j.biortech.2014.11.062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 11/13/2014] [Accepted: 11/14/2014] [Indexed: 06/04/2023]
Abstract
Uncertainty associated to the estimated values of the parameters in a model is a key piece of information for decision makers and model users. However, this information is typically not reported or the confidence intervals are too large to be useful. A semi-mechanistic model for the enzymatic saccharification of dilute acid pretreated corn stover is proposed in this work, the model is a modification of an existing one providing a statistically significant improved fit towards a set of experimental data that includes varying initial solid loadings (10-25% w/w) and the use of the pretreatment liquor and washed solids with or without supplementation of key inhibitors. A subset of 8 out of 17 parameters was identified, showing sufficiently tight confidence intervals to be used in uncertainty propagation and model analysis, without requiring interval truncation via expert judgment.
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Affiliation(s)
- Felipe Scott
- School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso, Chile; Bioenercel S.A. Barrio Universitario s/n, Ideaincuba building, Concepción, Chile.
| | - Muyang Li
- DOE-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA; Department of Biosystems & Agricultural Engineering, Michigan State University, 48824 East Lansing, MI, USA
| | - Daniel L Williams
- DOE-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA; Department of Chemical Engineering & Materials Science, Michigan State University, 48824 East Lansing, MI, USA
| | - Raúl Conejeros
- School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso, Chile; Bioenercel S.A. Barrio Universitario s/n, Ideaincuba building, Concepción, Chile
| | - David B Hodge
- DOE-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA; Department of Biosystems & Agricultural Engineering, Michigan State University, 48824 East Lansing, MI, USA; Department of Chemical Engineering & Materials Science, Michigan State University, 48824 East Lansing, MI, USA; Division of Chemical Engineering, Luleå University of Technology, Luleå, Sweden
| | - Germán Aroca
- School of Biochemical Engineering, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, Valparaíso, Chile; Bioenercel S.A. Barrio Universitario s/n, Ideaincuba building, Concepción, Chile
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78
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Elliston A, Wood IP, Soucouri MJ, Tantale RJ, Dicks J, Roberts IN, Waldron KW. Methodology for enabling high-throughput simultaneous saccharification and fermentation screening of yeast using solid biomass as a substrate. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:2. [PMID: 25648300 PMCID: PMC4314751 DOI: 10.1186/s13068-014-0181-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 12/08/2014] [Indexed: 06/04/2023]
Abstract
BACKGROUND High-throughput (HTP) screening is becoming an increasingly useful tool for collating biological data which would otherwise require the employment of excessive resources. Second generation biofuel production is one such process. HTP screening allows the investigation of large sample sets to be undertaken with increased speed and cost effectiveness. This paper outlines a methodology that will enable solid lignocellulosic substrates to be hydrolyzed and fermented at a 96-well plate scale, facilitating HTP screening of ethanol production, whilst maintaining repeatability similar to that achieved at a larger scale. RESULTS The results showed that utilizing sheets of biomass of consistent density (handbills), for paper, and slurries of pretreated biomass that could be pipetted allowed standardized and accurate transfers to 96-well plates to be achieved (±3.1 and 1.7%, respectively). Processing these substrates by simultaneous saccharification and fermentation (SSF) at various volumes showed no significant difference on final ethanol yields, either at standard shake flask (200 mL), universal bottle (10 mL) or 96-well plate (1 mL) scales. Substrate concentrations of up to 10% (w/v) were trialed successfully for SSFs at 1 mL volume. The methodology was successfully tested by showing the effects of steam explosion pretreatment on both oilseed rape and wheat straws. CONCLUSIONS This methodology could be used to replace large shake flask reactions with comparatively fast 96-well plate SSF assays allowing for HTP experimentation. Additionally this method is compatible with a number of standardized assay techniques such as simple colorimetric, High-performance liquid chromatography (HPLC) and Nuclear magnetic resonance (NMR) spectroscopy. Furthermore this research has practical uses in the biorefining of biomass substrates for second generation biofuels and novel biobased chemicals by allowing HTP SSF screening, which should allow selected samples to be scaled up or studied in more detail.
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Affiliation(s)
- Adam Elliston
- />The Biorefinery Centre, Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA UK
| | - Ian P Wood
- />The Biorefinery Centre, Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA UK
| | - Marie J Soucouri
- />The Biorefinery Centre, Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA UK
- />École supérieure d’ingénieurs Réunion Océan Indien, Génie Biologique, Université de La Réunion, Parc Technologique Universitaire, 2 Rue Joseph Wetzell, 97490 Sainte-Clotilde, La Réunion France
| | - Rachelle J Tantale
- />The Biorefinery Centre, Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA UK
- />Institut Universitaire de Technologie, Universite de la Reunion, 40 avenue de Soweto, BP 373, 97455 Saint-Pierre Cedex, La Réunion France
| | - Jo Dicks
- />The National Collection of Yeast Cultures, Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA UK
| | - Ian N Roberts
- />The National Collection of Yeast Cultures, Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA UK
| | - Keith W Waldron
- />The Biorefinery Centre, Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA UK
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79
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Cao LC, Wang ZJ, Ren GH, Kong W, Li L, Xie W, Liu YH. Engineering a novel glucose-tolerant β-glucosidase as supplementation to enhance the hydrolysis of sugarcane bagasse at high glucose concentration. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:202. [PMID: 26628916 PMCID: PMC4666061 DOI: 10.1186/s13068-015-0383-z] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 11/16/2015] [Indexed: 05/02/2023]
Abstract
BACKGROUND Most β-glucosidases reported are sensitive to the end product (glucose), making it the rate limiting component of cellulase for efficient degradation of cellulose through enzymatic route. Thus, there are ongoing interests in searching for glucose-tolerant β-glucosidases, which are still active at high glucose concentration. Although many β-glucosidases with different glucose-tolerance levels have been isolated and characterized in the past decades, the effects of glucose-tolerance on the hydrolysis of cellulose are not thoroughly studied. RESULTS In the present study, a novel β-glucosidase (Bgl6) with the half maximal inhibitory concentration (IC 50) of 3.5 M glucose was isolated from a metagenomic library and characterized. However, its poor thermostability at 50 °C hindered the employment in cellulose hydrolysis. To improve its thermostability, random mutagenesis was performed. A thermostable mutant, M3, with three amino acid substitutions was obtained. The half-life of M3 at 50 °C is 48 h, while that of Bgl6 is 1 h. The K cat/K m value of M3 is 3-fold higher than that of Bgl6. The mutations maintained its high glucose-tolerance with IC 50 of 3.0 M for M3. In a 10-h hydrolysis of cellobiose, M3 completely converted cellobiose to glucose, while Bgl6 reached a conversion of 80 %. Then their synergistic effects with the commercial cellulase (Celluclast 1.5 L) on hydrolyzing pretreated sugarcane bagasse (SCB) were investigated. The supplementation of Bgl6 or mutant M3 to Celluclast 1.5 L significantly improved the SCB conversion from 64 % (Celluclast 1.5 L alone) to 79 % (Bgl6) and 94 % (M3), respectively. To further evaluate the application potential of M3 in high-solids cellulose hydrolysis, such reactions were performed at initial glucose concentration of 20-500 mM. Results showed that the supplementation of mutant M3 enhanced the glucose production from SCB under all the conditions tested, improving the SCB conversion by 14-35 %. CONCLUSIONS These results not only clearly revealed the significant role of glucose-tolerance in cellulose hydrolysis, but also showed that mutant M3 may be a potent candidate for high-solids cellulose refining.
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Affiliation(s)
- Li-chuang Cao
- />School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
- />South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Zhi-jun Wang
- />School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
- />South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Guang-hui Ren
- />School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
- />South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Wei Kong
- />School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
- />South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Liang Li
- />School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
- />South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Wei Xie
- />State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
| | - Yu-huan Liu
- />School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
- />South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, Sun Yat-sen University, Guangzhou, 510275 People’s Republic of China
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80
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Visser EM, Leal TF, de Almeida MN, Guimarães VM. Increased enzymatic hydrolysis of sugarcane bagasse from enzyme recycling. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:5. [PMID: 25642284 PMCID: PMC4311420 DOI: 10.1186/s13068-014-0185-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 12/15/2014] [Indexed: 05/09/2023]
Abstract
BACKGROUND Development of efficient methods for production of renewable fuels from lignocellulosic biomass is necessary to maximize yields and reduce operating costs. One of the main challenges to industrial application of the lignocellulosic conversion process is the high costs of cellulolytic enzymes. Recycling of enzymes may present a potential solution to alleviate this problem. In the present study enzymes associated with the insoluble fraction were recycled after enzymatic hydrolysis of pretreated sugarcane bagasse, utilizing different processing conditions, enzyme loadings, and solid loadings. RESULTS It was found that the enzyme blend from Chrysoporthe cubensis and Penicillium pinophilum was efficient for enzymatic hydrolysis and that a significant portion of enzyme activity could be recovered upon recycling of the insoluble fraction. Enzyme productivity values (g glucose/mg enzyme protein) over all recycle periods were 2.4 and 3.7 for application of 15 and 30 FPU/g of glucan, representing an increase in excess of ten times that obtained in a batch process with the same enzyme blend and an even greater increase compared to commercial cellulase enzymes. CONCLUSIONS Contrary to what may be expected, increasing lignin concentrations throughout the recycle period did not negatively influence hydrolysis efficiency, but conversion efficiencies continuously improved. Recycling of the entire insoluble solids fraction was sufficient for recycling of adhered enzymes together with biomass, indicative of an effective method to increase enzyme productivity.
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Affiliation(s)
- Evan Michael Visser
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Campus Universitário, 36570-000 Viçosa, MG Brazil
| | - Tiago Ferreira Leal
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Campus Universitário, 36570-000 Viçosa, MG Brazil
| | - Maíra Nicolau de Almeida
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Campus Universitário, 36570-000 Viçosa, MG Brazil
| | - Valéria Monteze Guimarães
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Viçosa, Campus Universitário, 36570-000 Viçosa, MG Brazil
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81
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Geng W, Jin Y, Jameel H, Park S. Strategies to achieve high-solids enzymatic hydrolysis of dilute-acid pretreated corn stover. BIORESOURCE TECHNOLOGY 2015; 187:43-48. [PMID: 25836373 DOI: 10.1016/j.biortech.2015.03.067] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Revised: 03/11/2015] [Accepted: 03/12/2015] [Indexed: 05/08/2023]
Abstract
Three strategies were presented to achieve high solids loading while maximizing carbohydrate conversion, which are fed-batch, splitting/thickening, and clarifier processes. Enzymatic hydrolysis was performed at water insoluble solids (WIS) of 15% using washed dilute-acid pretreated corn stover. The carbohydrate concentration increased from 31.8 to 99.3g/L when the insoluble solids content increased from 5% to 15% WIS, while the final carbohydrate conversion was decreased from 78.4% to 73.2%. For the fed-batch process, a carbohydrate conversion efficiency of 76.8% was achieved when solid was split into 60:20:20 ratio, with all enzymes added first. For the splitting/thickening process, a carbohydrate conversion of 76.5% was realized when the filtrate was recycled to simulate a steady-state process. Lastly, the clarifier process was evaluated and the highest carbohydrate conversion of 81.4% was achieved. All of these results suggests the possibility of enzymatic hydrolysis at high solids to make the overall conversion cost-competitive.
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Affiliation(s)
- Wenhui Geng
- Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing 210037, China; Department of Forest Biomaterials, North Carolina State University, Raleigh, NC 27695-8005, USA
| | - Yongcan Jin
- Jiangsu Provincial Key Lab of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing 210037, China
| | - Hasan Jameel
- Department of Forest Biomaterials, North Carolina State University, Raleigh, NC 27695-8005, USA
| | - Sunkyu Park
- Department of Forest Biomaterials, North Carolina State University, Raleigh, NC 27695-8005, USA.
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82
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Effect of Double-Step Steam Explosion Pretreatment in Bioethanol Production from Softwood. Appl Biochem Biotechnol 2014; 174:156-67. [DOI: 10.1007/s12010-014-1046-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 07/07/2014] [Indexed: 10/25/2022]
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83
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The Role of Product Inhibition as a Yield-Determining Factor in Enzymatic High-Solid Hydrolysis of Pretreated Corn Stover. Appl Biochem Biotechnol 2014; 174:146-55. [DOI: 10.1007/s12010-014-1049-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Accepted: 07/07/2014] [Indexed: 10/25/2022]
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84
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Simultaneous saccharification and fermentation of pretreated sugarcane bagasse to ethanol using a new thermotolerant yeast. ANN MICROBIOL 2014. [DOI: 10.1007/s13213-014-0875-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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85
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Kinetics of enzymatic hydrolysis of olive oil in batch and fed-batch systems. Appl Biochem Biotechnol 2014; 173:1336-48. [PMID: 24793196 DOI: 10.1007/s12010-014-0943-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 04/21/2014] [Indexed: 10/25/2022]
Abstract
This work reports experimental data, kinetic modeling, and simulations of enzyme-catalyzed hydrolysis of olive oil. This reaction was performed in batch system and an ordered-sequential Bi Bi model was used to model the kinetic mechanism. A fed-batch system was proposed and experimental data were obtained and compared to the simulated values. The kinetic model used was able to correlate the experimental data, in which a satisfactory agreement between the experimental data and modeling results was obtained under different enzyme concentration and initial free water content. Therefore, the modeling allowed a better understanding of the reaction kinetics and affords a fed-batch simulation for this system. From the results obtained, it was observed that the fed-batch approach showed to be more advantageous when compared to the conventional batch system.
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86
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Ghorbanian M, Russ DC, Berson RE. Mixing analysis of PCS slurries in a horizontal scraped surface bioreactor. Bioprocess Biosyst Eng 2014; 37:2113-9. [DOI: 10.1007/s00449-014-1189-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 04/06/2014] [Indexed: 11/28/2022]
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87
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Liu T, Williams DL, Pattathil S, Li M, Hahn MG, Hodge DB. Coupling alkaline pre-extraction with alkaline-oxidative post-treatment of corn stover to enhance enzymatic hydrolysis and fermentability. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:48. [PMID: 24693882 PMCID: PMC3997815 DOI: 10.1186/1754-6834-7-48] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 03/18/2014] [Indexed: 05/04/2023]
Abstract
BACKGROUND A two-stage chemical pretreatment of corn stover is investigated comprising an NaOH pre-extraction followed by an alkaline hydrogen peroxide (AHP) post-treatment. We propose that conventional one-stage AHP pretreatment can be improved using alkaline pre-extraction, which requires significantly less H2O2 and NaOH. To better understand the potential of this approach, this study investigates several components of this process including alkaline pre-extraction, alkaline and alkaline-oxidative post-treatment, fermentation, and the composition of alkali extracts. RESULTS Mild NaOH pre-extraction of corn stover uses less than 0.1 g NaOH per g corn stover at 80°C. The resulting substrates were highly digestible by cellulolytic enzymes at relatively low enzyme loadings and had a strong susceptibility to drying-induced hydrolysis yield losses. Alkaline pre-extraction was highly selective for lignin removal over xylan removal; xylan removal was relatively minimal (~20%). During alkaline pre-extraction, up to 0.10 g of alkali was consumed per g of corn stover. AHP post-treatment at low oxidant loading (25 mg H2O2 per g pre-extracted biomass) increased glucose hydrolysis yields by 5%, which approached near-theoretical yields. ELISA screening of alkali pre-extraction liquors and the AHP post-treatment liquors demonstrated that xyloglucan and β-glucans likely remained tightly bound in the biomass whereas the majority of the soluble polymeric xylans were glucurono (arabino) xylans and potentially homoxylans. Pectic polysaccharides were depleted in the AHP post-treatment liquor relative to the alkaline pre-extraction liquor. Because the already-low inhibitor content was further decreased in the alkaline pre-extraction, the hydrolysates generated by this two-stage pretreatment were highly fermentable by Saccharomyces cerevisiae strains that were metabolically engineered and evolved for xylose fermentation. CONCLUSIONS This work demonstrates that this two-stage pretreatment process is well suited for converting lignocellulose to fermentable sugars and biofuels, such as ethanol. This approach achieved high enzymatic sugars yields from pretreated corn stover using substantially lower oxidant loadings than have been reported previously in the literature. This pretreatment approach allows for many possible process configurations involving novel alkali recovery approaches and novel uses of alkaline pre-extraction liquors. Further work is required to identify the most economical configuration, including process designs using techno-economic analysis and investigating processing strategies that economize water use.
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Affiliation(s)
- Tongjun Liu
- DOE-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA
- School of Food and Bioengineering, Qilu University of Technology, 250353 Jinan, China
| | - Daniel L Williams
- DOE-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA
- Department of Chemical Engineering and Materials Science, Michigan State University, 48824 East Lansing, MI, USA
| | - Sivakumar Pattathil
- Complex Carbohydrate Research Center, The University of Georgia, 315 Riverbend Rd, 30602 Athens, GA, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, 37831 Oak Ridge, TN, USA
| | - Muyang Li
- DOE-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA
- Department of Biosystems and Agriculture Engineering, Michigan State University, 48824 East Lansing, MI, USA
| | - Michael G Hahn
- Complex Carbohydrate Research Center, The University of Georgia, 315 Riverbend Rd, 30602 Athens, GA, USA
- BioEnergy Science Center (BESC), Oak Ridge National Laboratory, 37831 Oak Ridge, TN, USA
- Department of Plant Biology, University of Georgia, 30602 Athens, GA, USA
| | - David B Hodge
- DOE-Great Lakes Bioenergy Research Center, Michigan State University, East Lansing, MI, USA
- Department of Chemical Engineering and Materials Science, Michigan State University, 48824 East Lansing, MI, USA
- Department of Biosystems and Agriculture Engineering, Michigan State University, 48824 East Lansing, MI, USA
- Division of Sustainable Process Engineering, Luleå University of Technology, 97187 Luleå, Sweden
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88
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Hardt N, Janssen A, Boom R, van der Goot A. Factors impeding enzymatic wheat gluten hydrolysis at high solid concentrations. Biotechnol Bioeng 2014; 111:1304-12. [DOI: 10.1002/bit.25197] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 01/14/2014] [Accepted: 01/21/2014] [Indexed: 11/11/2022]
Affiliation(s)
- N.A. Hardt
- Laboratory of Food Process Engineering; Wageningen University; PO Box 8129 Wageningen 6700 EV The Netherlands
| | - A.E.M. Janssen
- Laboratory of Food Process Engineering; Wageningen University; PO Box 8129 Wageningen 6700 EV The Netherlands
| | - R.M. Boom
- Laboratory of Food Process Engineering; Wageningen University; PO Box 8129 Wageningen 6700 EV The Netherlands
| | - A.J. van der Goot
- Laboratory of Food Process Engineering; Wageningen University; PO Box 8129 Wageningen 6700 EV The Netherlands
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89
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Bhutto AW, Qureshi K, Harijan K, Zahedi G, Bahadori A. Strategies for the consolidation of biologically mediated events in the conversion of pre-treated lignocellulose into ethanol. RSC Adv 2014. [DOI: 10.1039/c3ra44020f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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90
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Cotana F, Cavalaglio G, Gelosia M, Nicolini A, Coccia V, Petrozzi A. Production of Bioethanol in a Second Generation Prototype from Pine Wood Chips. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.egypro.2014.01.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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91
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Santala O, Nordlund E, Poutanen K. Use of an extruder for pre-mixing enhances xylanase action on wheat bran at low water content. BIORESOURCE TECHNOLOGY 2013; 149:191-199. [PMID: 24103644 DOI: 10.1016/j.biortech.2013.09.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Revised: 09/03/2013] [Accepted: 09/06/2013] [Indexed: 06/02/2023]
Abstract
The aim of the work was to test the hypothesis that at low water content enzyme action on biomass is enhanced when the raw material is in the form of a continuous mass instead of powder/granular form. Effects of two pre-mixing methods, blade-mixing and extrusion, on xylanase action were studied during stationary incubation of wheat bran of different particle sizes, also in comparison with incubation at high water content with continuous stirring. The use of an extruder enhanced arabinoxylan (AX) solubilisation at low water content (<54%), as compared to blade-mixing. AX solubilisation was highest in the high-water stirring treatment, but based on molecular weight, xylanase action on solubilised AX was similar as in the extrusion-aided process. Pre-mixing by extrusion enabled efficient enzyme action at low water content without the requirement for continuous mixing, probably due to the enhanced diffusion by the formation of a continuous mass in the extruder.
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Affiliation(s)
- Outi Santala
- VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT Espoo, Finland.
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92
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Prunescu RM, Sin G. Dynamic modeling and validation of a lignocellulosic enzymatic hydrolysis process--a demonstration scale study. BIORESOURCE TECHNOLOGY 2013; 150:393-403. [PMID: 24212094 DOI: 10.1016/j.biortech.2013.10.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/02/2013] [Accepted: 10/09/2013] [Indexed: 06/02/2023]
Abstract
The enzymatic hydrolysis process is one of the key steps in second generation biofuel production. After being thermally pretreated, the lignocellulosic material is liquefied by enzymes prior to fermentation. The scope of this paper is to evaluate a dynamic model of the hydrolysis process on a demonstration scale reactor. The following novel features are included: the application of the Convection-Diffusion-Reaction equation to a hydrolysis reactor to assess transport and mixing effects; the extension of a competitive kinetic model with enzymatic pH dependency and hemicellulose hydrolysis; a comprehensive pH model; and viscosity estimations during the course of reaction. The model is evaluated against real data extracted from a demonstration scale biorefinery throughout several days of operation. All measurements are within predictions uncertainty and, therefore, the model constitutes a valuable tool to support process optimization, performance monitoring, diagnosis and process control at full-scale studies.
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Affiliation(s)
- Remus Mihail Prunescu
- Department of Electrical Engineering, Automation and Control Group, Technical University of Denmark, Elektrovej Building 326, 2800 Kgs. Lyngby, Denmark.
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93
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High solids enzymatic hydrolysis of pretreated lignocellulosic materials with a powerful stirrer concept. Appl Biochem Biotechnol 2013; 172:1699-713. [PMID: 24242162 DOI: 10.1007/s12010-013-0607-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 10/23/2013] [Indexed: 10/26/2022]
Abstract
In this study, we present a powerful stirred tank reactor system that can efficiently hydrolyse lignocellulosic material at high solid content to produce hydrolysates with glucose concentration > 100 g/kg. As lignocellulosic substrates alkaline-pretreated wheat straw and organosolv-pretreated beech wood were used. The developed vertical reactor was equipped with a segmented helical stirrer, which was specially designed for high biomass hydrolysis. The stirrer was characterised according to mixing behaviour and power input. To minimise the cellulase dosage, a response surface plan was used. With the empirical relationship between glucose yield, cellulase loading and solid content, the minimal cellulase dosage was calculated to reach at least 70% yield at high glucose and high substrate concentrations within 48 h. The optimisation resulted in a minimal enzyme dosage of 30 FPU/g dry matter (DM) for the hydrolysis of wheat straw and 20 FPU/g DM for the hydrolysis of beech wood. By transferring the hydrolysis reaction from shaking flasks to the stirred tank reactor, the glucose yields could be increased. Using the developed stirred tank reactor system, alkaline-pretreated wheat straw could be converted to 110 g/kg glucose (76%) at a solid content of 20% (w/w) after 48 h. Organosolv-pretreated beech wood could be efficiently hydrolysed even at 30% (w/w) DM, giving 150 g/kg glucose (72%).
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94
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Bals BD, Gunawan C, Moore J, Teymouri F, Dale BE. Enzymatic hydrolysis of pelletized AFEX™-treated corn stover at high solid loadings. Biotechnol Bioeng 2013; 111:264-71. [DOI: 10.1002/bit.25022] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 06/24/2013] [Accepted: 08/05/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Bryan D. Bals
- MBI; 3815 Technology Boulevard Lansing Michigan 48910-8596
| | - Christa Gunawan
- Department of Chemical Engineering and Materials Science; Michigan State University; Lansing Michigan
- Great Lakes Bioenergy Research Center; Michigan State University; East Lansing Michigan
| | - Janette Moore
- MBI; 3815 Technology Boulevard Lansing Michigan 48910-8596
| | | | - Bruce E. Dale
- Department of Chemical Engineering and Materials Science; Michigan State University; Lansing Michigan
- Great Lakes Bioenergy Research Center; Michigan State University; East Lansing Michigan
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95
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Fujii T, Murakami K, Endo T, Fujimoto S, Minowa T, Matsushika A, Yano S, Sawayama S. Bench-scale bioethanol production from eucalyptus by high solid saccharification and glucose/xylose fermentation method. Bioprocess Biosyst Eng 2013; 37:749-54. [PMID: 23917411 PMCID: PMC3968441 DOI: 10.1007/s00449-013-1032-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 07/29/2013] [Indexed: 11/23/2022]
Abstract
In the bioethanol production process, high solid saccharification and glucose/xylose co-fermentation are important technologies for obtaining increased ethanol concentrations; however, bench-scale studies using combinations of these methods are limited. In this study, we hydrolyzed high solid concentration of milled eucalyptus using commercial enzymes and obtained 138.4 g/L total monomeric sugar concentration. These sugars were fermented to 53.5 g/L of ethanol by a xylose-utilizing recombinant Saccharomyces cerevisiae strain, MA-R4. These experiments were performed in bench scale (using 50 L scale solid mixer and 70 L scale fermenter). The results obtained in this study were comparable to our previous results in laboratory scale, indicating that we successfully achieved an efficient high solid saccharification and glucose/xylose co-fermentation system in bench scale.
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Affiliation(s)
- Tatsuya Fujii
- Biomass Refinery Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 3-11-32 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-0046, Japan,
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96
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Du J, Zhang F, Li Y, Zhang H, Liang J, Zheng H, Huang H. Enzymatic liquefaction and saccharification of pretreated corn stover at high-solids concentrations in a horizontal rotating bioreactor. Bioprocess Biosyst Eng 2013; 37:173-81. [PMID: 23771162 DOI: 10.1007/s00449-013-0983-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 05/20/2013] [Indexed: 10/26/2022]
Abstract
A self-designed horizontal rotating bioreactor (HRR) was applied for enzymatic hydrolysis of pretreated corn stover to improve the process economics of ethanol production. The mixing principle was based on gravity and free fall employed with tank-rotating. The liquefaction performances using the HRR and the vertical stirred-tank reactor (VSTR) with a helical impeller were compared and analyzed by measuring rheological properties of the slurry. During the enzymatic hydrolysis, viscosity decreased dramatically in the initial phase for both bioreactors and more pronouncedly for the HRR. Rheological parameters fitted to the power law showed that shear thinning properties of the slurry weakened during the reaction. The glucose concentration was used to define the efficiency of the saccharification reaction. The HRR also proved to be more efficient for glucose release with both the constant and fed-batch substrate addition modes. Liquefaction and saccharification at 25% w/w dry matter (DM) and enzyme loading of 7 FPU/g DM resulted in the optimal glucose concentration of 86 g/kg. Results revealed a decrease in cellulose conversion at increasing initial DM, which was slighter in the HRR compared with that in the VSTR.
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Affiliation(s)
- Jian Du
- College of Life Science and Pharmacy, Nanjing University of Technology, Nanjing, 210009, Jiangsu, China,
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97
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de Andrade RR, Maugeri Filho F, Maciel Filho R, da Costa AC. Kinetics of ethanol production from sugarcane bagasse enzymatic hydrolysate concentrated with molasses under cell recycle. BIORESOURCE TECHNOLOGY 2013; 130:351-359. [PMID: 23313680 DOI: 10.1016/j.biortech.2012.12.045] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 11/01/2012] [Accepted: 12/02/2012] [Indexed: 06/01/2023]
Abstract
In this work, a kinetic model for ethanol fermentation from sugarcane bagasse enzymatic hydrolysate concentrated with molasses was developed. A model previously developed for fermentation of pure molasses was modified by the inclusion of a new term for acetic acid inhibition on microorganism growth rate and the kinetic parameters were estimated as functions of temperature. The influence of the hydrolysate on the kinetic parameters is analyzed by comparing with the parameters from fermentation of pure molasses. The impact of cells recycling in the kinetic parameters is also evaluated, as well as on the ethanol yield and productivity. The model developed described accurately most of the fermentations performed in several successive batches for temperatures from 30 to 38°C.
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Affiliation(s)
- Rafael Ramos de Andrade
- Faculdade de Engenharia Química, Universidade Estadual de Campinas (UNICAMP), Caixa Postal 6066, 13083-970 Campinas, São Paulo, Brazil.
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98
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Gupta R, Kumar S, Gomes J, Kuhad RC. Kinetic study of batch and fed-batch enzymatic saccharification of pretreated substrate and subsequent fermentation to ethanol. BIOTECHNOLOGY FOR BIOFUELS 2012; 5:16. [PMID: 22433563 PMCID: PMC3369211 DOI: 10.1186/1754-6834-5-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 03/20/2012] [Indexed: 05/24/2023]
Abstract
BACKGROUND Enzymatic hydrolysis, the rate limiting step in the process development for biofuel, is always hampered by its low sugar concentration. High solid enzymatic saccharification could solve this problem but has several other drawbacks such as low rate of reaction. In the present study we have attempted to enhance the concentration of sugars in enzymatic hydrolysate of delignified Prosopis juliflora, using a fed-batch enzymatic hydrolysis approach. RESULTS The enzymatic hydrolysis was carried out at elevated solid loading up to 20% (w/v) and a comparison kinetics of batch and fed-batch enzymatic hydrolysis was carried out using kinetic regimes. Under batch mode, the actual sugar concentration values at 20% initial substrate consistency were found deviated from the predicted values and the maximum sugar concentration obtained was 80.78 g/L. Fed-batch strategy was implemented to enhance the final sugar concentration to 127 g/L. The batch and fed-batch enzymatic hydrolysates were fermented with Saccharomyces cerevisiae and ethanol production of 34.78 g/L and 52.83 g/L, respectively, were achieved. Furthermore, model simulations showed that higher insoluble solids in the feed resulted in both smaller reactor volume and shorter residence time. CONCLUSION Fed-batch enzymatic hydrolysis is an efficient procedure for enhancing the sugar concentration in the hydrolysate. Restricting the process to suitable kinetic regimes could result in higher conversion rates.
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Affiliation(s)
- Rishi Gupta
- Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South Campus, New Delhi 110021, India
| | - Sanjay Kumar
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - James Gomes
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Ramesh Chander Kuhad
- Lignocellulose Biotechnology Laboratory, Department of Microbiology, University of Delhi South Campus, New Delhi 110021, India
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99
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Banerjee G, Car S, Liu T, Williams DL, Meza SL, Walton JD, Hodge DB. Scale-up and integration of alkaline hydrogen peroxide pretreatment, enzymatic hydrolysis, and ethanolic fermentation. Biotechnol Bioeng 2011; 109:922-31. [DOI: 10.1002/bit.24385] [Citation(s) in RCA: 97] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 11/09/2011] [Accepted: 11/14/2011] [Indexed: 11/09/2022]
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100
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Carvajal D, Marchisio DL, Bensaid S, Fino D. Enzymatic Hydrolysis of Lignocellulosic Biomasses via CFD and Experiments. Ind Eng Chem Res 2011. [DOI: 10.1021/ie201673t] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Danilo Carvajal
- Department of Materials Science and Chemical Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
- Escuela de Ingeniería Química, Pontificia Universidad Católica de Valparaíso, Av. Brasil 2147, 2362804 Valparaíso, Chile
| | - Daniele L. Marchisio
- Department of Materials Science and Chemical Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
| | - Samir Bensaid
- Department of Materials Science and Chemical Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
| | - Debora Fino
- Department of Materials Science and Chemical Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
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