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Tang C, Gandla ML, Jönsson LJ. LPMO-supported saccharification of biomass: effects of continuous aeration of reaction mixtures with variable fractions of water-insoluble solids and cellulolytic enzymes. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:156. [PMID: 37865768 PMCID: PMC10590502 DOI: 10.1186/s13068-023-02407-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 10/10/2023] [Indexed: 10/23/2023]
Abstract
BACKGROUND High substrate concentrations and high sugar yields are important aspects of enzymatic saccharification of lignocellulosic substrates. The benefit of supporting the catalytic action of lytic polysaccharide monooxygenase (LPMO) through continuous aeration of slurries of pretreated softwood was weighed against problems associated with increasing substrate content (quantitated as WIS, water-insoluble solids, in the range 12.5-17.5%), and was compared to the beneficial effect on the saccharification reaction achieved by increasing the enzyme preparation (Cellic CTec3) loadings. Aerated reactions were compared to reactions supplied with N2 to assess the contribution of LPMO to the saccharification reactions. Analysis using 13C NMR spectroscopy, XRD, Simons' staining, BET analysis, and SEM analysis was used to gain further insights into the effects of the cellulolytic enzymes on the substrate under different reaction conditions. RESULTS Although glucose production after 72 h was higher at 17.5% WIS than at 12.5% WIS, glucan conversion decreased with 24% (air) and 17% (N2). Compared to reactions with N2, the average increases in glucose production for aerated reactions were 91% (12.5% WIS), 70% (15.0% WIS), and 67% (17.5% WIS). Improvements in glucan conversion through aeration were larger (55-86%) than the negative effects of increasing WIS content. For reactions with 12.5% WIS, increased enzyme dosage with 50% improved glucan conversion with 25-30% for air and N2, whereas improvements with double enzyme dosage were 30% (N2) and 39% (air). Structural analyses of the solid fractions revealed that the enzymatic reaction, particularly with aeration, created increased surface area (BET analysis), increased disorder (SEM analysis), decreased crystallinity (XRD), and increased dye adsorption based on the cellulose content (Simons' staining). CONCLUSIONS The gains in glucan conversion with aeration were larger than the decreases observed due to increased substrate content, resulting in higher glucan conversion when using aeration at the highest WIS value than when using N2 at the lowest WIS value. The increase in glucan conversion with double enzyme preparation dosage was smaller than the increase achieved with aeration. The results demonstrate the potential in using proper aeration to exploit the inherent capacity of LPMO in enzymatic saccharification of lignocellulosic substrates and provide detailed information about the characteristics of the substrate after interaction with cellulolytic enzymes.
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Affiliation(s)
- Chaojun Tang
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden
| | | | - Leif J Jönsson
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden.
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2
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Negi A, Kesari KK. Light-Driven Depolymerization of Cellulosic Biomass into Hydrocarbons. Polymers (Basel) 2023; 15:3671. [PMID: 37765525 PMCID: PMC10537178 DOI: 10.3390/polym15183671] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/18/2023] [Accepted: 08/22/2023] [Indexed: 09/29/2023] Open
Abstract
Cellulose and hemicellulose are the main constituents of lignocellulosic biomass. Chemical derivatization of lignocellulosic biomass leads to a range of C5 and C6 organic compounds. These C5 and C6 compounds are valuable precursors (or fine chemicals) for developing sustainable chemical processes. Therefore, depolymerization of cellulose and hemicellulose is essential, leading to the development of various materials that have applications in biomaterial industries. However, most depolymerized processes for cellulose have limited success because of its structural quality: crystallinity, high hydrogen-bond networking, and mild solubility in organic and water. As a result, various chemical treatments, acidic (mineral or solid acids) and photocatalysis, have developed. One of the significant shortcomings of acidic treatment is that the requirement for high temperatures increases the commercial end cost (energy) and hampers product selectivity. For example, a catalyst with prolonged exposure to high temperatures damages the catalyst surface over time; therefore, it cannot be used for iterative cycles. Photocatalysts provide ample application to overcome such flaws as they do not require high temperatures to perform efficient catalysis. Various photocatalysts have shown efficient cellulosic biomass conversion into its C6 and C5 hydrocarbons and the production of hydrogen (as a green energy component). For example, TiO2-based photocatalysts are the most studied for biomass valorization. Herein, we discussed the feasibility of a photocatalyst with application to cellulosic biomass hydrolysis.
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Affiliation(s)
- Arvind Negi
- Department of Bioproduct and Biosystems, Aalto University, 02150 Espoo, Finland
| | - Kavindra Kumar Kesari
- Department of Bioproduct and Biosystems, Aalto University, 02150 Espoo, Finland
- Department of Applied Physics, School of Science, Aalto University, 02150 Espoo, Finland
- Research and Development Cell, Lovely Professional University, Phagwara 144411, Punjab, India
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3
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Prospects of thermotolerant Kluyveromyces marxianus for high solids ethanol fermentation of lignocellulosic biomass. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:134. [PMID: 36474296 PMCID: PMC9724321 DOI: 10.1186/s13068-022-02232-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 10/20/2022] [Indexed: 12/12/2022]
Abstract
Simultaneous saccharification and fermentation (SSF) is effective for minimizing sugar inhibition during high solids fermentation of biomass solids to ethanol. However, fungal enzymes used during SSF are optimal between 50 and 60 °C, whereas most fermentative yeast, such as Saccharomyces cerevisiae, do not tolerate temperatures above 37 °C. Kluyveromyces marxianus variant CBS 6556 is a thermotolerant eukaryote that thrives at 43 °C, thus potentially serving as a promising new host for SSF operation in biorefineries. Here, we attempt to leverage the thermotolerance of the strain to demonstrate the application of CBS 6556 in a high solids (up to 20 wt% insoluble solid loading) SSF configuration to understand its capabilities and limitations as compared to a proven SSF strain, S. cerevisiae D5A. For this study, we first pretreated hardwood poplar chips using Co-Solvent Enhanced Lignocellulosic Fractionation (CELF) to remove lignin and hemicellulose and to produce cellulose-enriched pretreated solids for SSF. Our results demonstrate that although CBS 6556 could not directly outperform D5A, it demonstrated similar tolerance to high gravity sugar solutions, superior growth rates at higher temperatures and higher early stage ethanol productivity. We discovered that CBS 6556's membrane was particularly sensitive to higher ethanol concentrations causing it to suffer earlier fermentation arrest than D5A. Cross-examination of metabolite data between CBS 6556 and D5A and cell surface imaging suggests that the combined stresses of high ethanol concentrations and temperature to CBS 6556's cell membrane was a primary factor limiting its ethanol productivity. Hence, we believe K. marxianus to be an excellent host for future genetic engineering efforts to improve membrane robustness especially at high temperatures in order to achieve higher ethanol productivity and titers, serving as a viable alternative to D5A.
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Dos Santos ACF, Overton JC, Szeto R, Patel MH, Gutierrez DMR, Eby C, Martínez Moreno AM, Erk KA, Aston JE, Thompson DN, Dooley JH, Sharma P, Mosier NS, Ximenes E, Ladisch MR. New strategy for liquefying corn stover pellets. BIORESOURCE TECHNOLOGY 2021; 341:125773. [PMID: 34419879 DOI: 10.1016/j.biortech.2021.125773] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/10/2021] [Accepted: 08/11/2021] [Indexed: 06/13/2023]
Abstract
The movement of solid material into and between unit operations within a biorefinery is a bottleneck in reaching design capacity, with formation of biomass slurries needed to introduce feedstock. Corn stover slurries have been achieved from dilute acid, pretreated materials resulting in slurry concentrations of up to about 150 g/L, above which flowability is compromised. We report a new strategy to liquefy corn stover at higher solids concentration (300 g/L) by initially cooking it with the enzyme mimetic maleic acid at 40 mM and 150 °C. This is followed by 6 h of enzymatic modification at 1 FPU (2.2 mg protein)/g solids, resulting in a yield stress of 171 Pa after 6 h and 58 Pa in 48 h compared to 6806 Pa for untreated stover. Mimetic treatment of corn stover pellets minimizes the inhibitory effect of xylo-oligomers on hydrolytic enzymes. This strategy allows for the delivery of solid lignocellulosic slurry into a pretreatment reactor by pumping, improving operability of a biorefinery.
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Affiliation(s)
- Antonio C Freitas Dos Santos
- Laboratory of Renewable Resources Engineering (LORRE), Purdue University, West Lafayette, IN 47907 United States; Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907 United States
| | - Jonathan C Overton
- Laboratory of Renewable Resources Engineering (LORRE), Purdue University, West Lafayette, IN 47907 United States; Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907 United States
| | - Ryan Szeto
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907 United States
| | - Maulik H Patel
- Laboratory of Renewable Resources Engineering (LORRE), Purdue University, West Lafayette, IN 47907 United States; Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907 United States
| | - Diana M R Gutierrez
- Laboratory of Renewable Resources Engineering (LORRE), Purdue University, West Lafayette, IN 47907 United States; Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907 United States
| | - Clark Eby
- Laboratory of Renewable Resources Engineering (LORRE), Purdue University, West Lafayette, IN 47907 United States; Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907 United States
| | - Ana M Martínez Moreno
- Laboratory of Renewable Resources Engineering (LORRE), Purdue University, West Lafayette, IN 47907 United States; Departmento de Ingeniería Química y Ambiental, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Kendra A Erk
- School of Materials Engineering, Purdue University, West Lafayette, IN 47907 United States
| | - John E Aston
- Chemical Systems, Idaho National Laboratory, Idaho Falls, Idaho 83415 United States
| | - David N Thompson
- Biomass Characterization, Idaho National Laboratory, Idaho Falls, Idaho 83415 United States
| | - James H Dooley
- Forest Concepts LLC., Auburn, Washington 98001 United States
| | - Pankaj Sharma
- Discovery Park, Purdue University, West Lafayette, IN 47907 United States
| | - Nathan S Mosier
- Laboratory of Renewable Resources Engineering (LORRE), Purdue University, West Lafayette, IN 47907 United States; Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907 United States
| | - Eduardo Ximenes
- Laboratory of Renewable Resources Engineering (LORRE), Purdue University, West Lafayette, IN 47907 United States; Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907 United States
| | - Michael R Ladisch
- Laboratory of Renewable Resources Engineering (LORRE), Purdue University, West Lafayette, IN 47907 United States; Department of Agricultural and Biological Engineering, Purdue University, West Lafayette, IN 47907 United States; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907 United States.
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Hoppert L, Einfalt D. Impact of particle size reduction on high gravity enzymatic hydrolysis of steam-exploded wheat straw. SN APPLIED SCIENCES 2021. [DOI: 10.1007/s42452-021-04870-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
AbstractEconomically feasible bioethanol production from lignocellulosic biomass requires solid loadings ≥ 15% dry matter (DM, w/w). However, increased solid loadings can lead to process difficulties, which are characterized by high apparent slurry viscosity, insufficient substrate mixing and limited water availability, resulting in reduced final glucose yields. To overcome these limitations, this study focused on enzymatic hydrolysis of 10–35% DM solid loadings with steam-exploded wheat straw in two different particle sizes. At solid loadings of 20 and 25% DM small particle size of ≤ 2.5 mm yielded 16.9 ± 1.1% and 10.2 ± 1.4% increased final glucose concentrations compared to large particle size of 30 ± 20 mm. Small particle size also positively influenced slurry viscosity and, therefore, miscibility. As a key finding of this investigation, high gravity enzymatic hydrolysis with solid loadings of 30–35% DM was indeed successfully employed when wheat straw was applied in small particle size. Here, the highest final glucose yield was achieved with 127.9 ± 4.9 g L−1 at 35% DM solid loading. An increase in the solid loading from 10 to 35% DM in small particle size experiments resulted in a 460% increase in the final glucose concentration.
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Jin C, Bao J. Lysine Production by Dry Biorefining of Wheat Straw and Cofermentation of Corynebacterium glutamicum. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:1900-1906. [PMID: 33539090 DOI: 10.1021/acs.jafc.0c07902] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
A preliminary study shows that lysine production from lignocellulose feedstock is feasible, but the conversion of xylose in lignocellulose to lysine remains unsolved. Two technical barriers are responsible for the remaining xylose conversion: one is the xylose loss into the wastewater stream of the biorefinery processing chain, and the other is the lack of efficient lysine-producing strain with xylose utilization. Here, we conducted a new biorefinery approach of consequent dry acid pretreatment and biodetoxification, resulting in zero wastewater generation and then well-preserved xylose. To provide the lysine-producing strain with xylose utilization, we modified the Corynebacterium glutamicum by establishing the xylose assimilation pathway and improving the NADPH cofactor regeneration. The combinational modification of biorefinery processing and strain development led to 31.3 g/L of lysine production with a yield of 0.23 g lysine per gram of wheat straw derived sugars. This study provides a practical method for upgraded lysine production from lignocellulose for future industrial applications.
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Affiliation(s)
- Ci Jin
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
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7
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Zheng L, Han X, Han T, Liu G, Bao J. Formulating a fully converged biorefining chain with zero wastewater generation by recycling stillage liquid to dry acid pretreatment operation. BIORESOURCE TECHNOLOGY 2020; 318:124077. [PMID: 32916463 DOI: 10.1016/j.biortech.2020.124077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/30/2020] [Accepted: 08/31/2020] [Indexed: 06/11/2023]
Abstract
Huge wastewater generation is the major challenge of biorefinery technology for production of cellulosic ethanol. This study designed and verified a method for completely recycling of wastewater stream (the stillage liquid from the beer column) in cellulosic ethanol production by dry biorefining processing. When the stillage liquid was directly recycled to dry acid pretreatment operation, ethanol production gradually reduced after two recycles primarily because the inorganic compounds accumulated by around 139%. To ultimately solve this technical barrier, the stillage liquid was evaporated and condensed into distillated water, then recycled to the pretreatment for complete dry biorefining process. This strategy supported a stable cellulosic ethanol production, and the overall mass and heat balance confirmed that only 65% of the lignin residue consumption was used for wastewater evaporation with 35% surplus for electricity generation. This study provided a fully converged biorefining process with a closed-loop wastewater recycling.
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Affiliation(s)
- Lixiang Zheng
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Xushen Han
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Tao Han
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Gang Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
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8
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Selective pressure on an interfacial enzyme: Functional roles of a highly conserved asparagine residue in a cellulase. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140359. [PMID: 31911207 DOI: 10.1016/j.bbapap.2019.140359] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 12/18/2019] [Accepted: 12/25/2019] [Indexed: 11/24/2022]
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9
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da Silva AS, Espinheira RP, Teixeira RSS, de Souza MF, Ferreira-Leitão V, Bon EPS. Constraints and advances in high-solids enzymatic hydrolysis of lignocellulosic biomass: a critical review. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:58. [PMID: 32211072 PMCID: PMC7092515 DOI: 10.1186/s13068-020-01697-w] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 03/11/2020] [Indexed: 05/22/2023]
Abstract
The industrial production of sugar syrups from lignocellulosic materials requires the conduction of the enzymatic hydrolysis step at high-solids loadings (i.e., with over 15% solids [w/w] in the reaction mixture). Such conditions result in sugar syrups with increased concentrations and in improvements in both capital and operational costs, making the process more economically feasible. However, this approach still poses several technical hindrances that impact the process efficiency, known as the "high-solids effect" (i.e., the decrease in glucan conversion yields as solids load increases). The purpose of this review was to present the findings on the main limitations and advances in high-solids enzymatic hydrolysis in an updated and comprehensive manner. The causes for the rheological limitations at the onset of the high-solids operation as well as those influencing the "high-solids effect" will be discussed. The subject of water constraint, which results in a highly viscous system and impairs mixing, and by extension, mass and heat transfer, will be analyzed under the perspective of the limitations imposed to the action of the cellulolytic enzymes. The "high-solids effect" will be further discussed vis-à-vis enzymes end-product inhibition and the inhibitory effect of compounds formed during the biomass pretreatment as well as the enzymes' unproductive adsorption to lignin. This review also presents the scientific and technological advances being introduced to lessen high-solids hydrolysis hindrances, such as the development of more efficient enzyme formulations, biomass and enzyme feeding strategies, reactor and impeller designs as well as process strategies to alleviate the end-product inhibition. We surveyed the academic literature in the form of scientific papers as well as patents to showcase the efforts on technological development and industrial implementation of the use of lignocellulosic materials as renewable feedstocks. Using a critical approach, we expect that this review will aid in the identification of areas with higher demand for scientific and technological efforts.
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Affiliation(s)
- Ayla Sant’Ana da Silva
- Biocatalysis Laboratory, National Institute of Technology, Ministry of Science, Technology, Innovation and Communication, Rio de Janeiro, RJ 20081-312 Brazil
- Bioethanol Laboratory, Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-909 Brazil
| | - Roberta Pereira Espinheira
- Biocatalysis Laboratory, National Institute of Technology, Ministry of Science, Technology, Innovation and Communication, Rio de Janeiro, RJ 20081-312 Brazil
- Bioethanol Laboratory, Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-909 Brazil
| | - Ricardo Sposina Sobral Teixeira
- Bioethanol Laboratory, Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-909 Brazil
| | - Marcella Fernandes de Souza
- Laboratory of Analytical Chemistry and Applied Ecochemistry, Department of Green Chemistry and Technology, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Viridiana Ferreira-Leitão
- Biocatalysis Laboratory, National Institute of Technology, Ministry of Science, Technology, Innovation and Communication, Rio de Janeiro, RJ 20081-312 Brazil
- Bioethanol Laboratory, Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-909 Brazil
| | - Elba P. S. Bon
- Bioethanol Laboratory, Department of Biochemistry, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, RJ 21941-909 Brazil
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Tasselli G, Filippucci S, D'Antonio S, Cavalaglio G, Turchetti B, Cotana F, Buzzini P. Optimization of enzymatic hydrolysis of cellulosic fraction obtained from stranded driftwood feedstocks for lipid production by Solicoccozyma terricola. ACTA ACUST UNITED AC 2019; 24:e00367. [PMID: 31453116 PMCID: PMC6704348 DOI: 10.1016/j.btre.2019.e00367] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 07/04/2019] [Accepted: 08/06/2019] [Indexed: 12/01/2022]
Abstract
Stranded driftwood feedstocks (SD) were steam exploded and hydrolyzed. The enzymatic hydrolysis was optimized using a multivariate approach (RSM). The conversion of carbohydrates into lipids by S. terricola was high (YL = 25.26%). The fatty acid profile achieved was similar to that reported for palm oil. SD feedstocks resulted a cheap C-source for biofuels and biochemicals production.
Stranded driftwood feedstocks may represent, after pretreatment with steam explosion and enzymatic hydrolysis, a cheap C-source for producing biochemicals and biofuels using oleaginous yeasts. The hydrolysis was optimized using a response surface methodology (RSM). The solid loading (SL) and the dosage of enzyme cocktail (ED) were variated following a central composite design (CCD) aimed at optimizing the conversion of carbohydrates into lipids (YL) by the yeast Solicoccozyma terricola DBVPG 5870. A second-order polynomial equation was computed for describing the effect of ED and SL on YL. The best combination (ED = 3.10%; SL = 22.07%) for releasing the optimal concentration of carbohydrates which gave the highest predicted YL (27.32%) was then validated by a new hydrolysis. The resulting value of YL (25.26%) was close to the theoretical maximum value. Interestingly, fatty acid profile achieved under the optimized conditions was similar to that reported for palm oil.
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Key Words
- A600, absorbance at 600 nm
- ANOVA, analysis of variance
- C/N, carbon/nitrogen
- C10:0, capric acid (decanoic acid)
- C12:0, lauric acid (dodecanoic acid)
- C14:0, myristic acid (tetradecanoic acid)
- C16:0, palmitic acid (hexadecanoic acid)
- C18:0, stearic acid (octadecanoic acid)
- C20:0, arachic acid (eicosanoic acid)
- C22:0, behenic acid (docosanoic acid)
- C24:0, lignoceric acid (tetracosanoic acid)
- C5, carbohydrates with five carbon atoms
- C6, carbohydrates with six carbon atoms
- C8:0, caprylic acid (octanoic acid)
- CBU, cellobiase unit
- CCD, Central Composite Design
- DW, dry weight
- ED, enzyme dosage
- Enzymatic hydrolysis
- Eq, equation
- F.A.M.E., fatty acid methyl ester
- FA, fatty acid
- FPU, filterpaper unit
- GC, Gas Chromatography
- GC-FID, Gas Chromatography – Flame Ionization Detector
- HLF, hydrolyzed liquid fraction
- HPLC, high performance liquid chromatography
- LF, liquid fraction
- NREL, National Renewable Energy Laboratory
- PL, total lipid production
- PL/DW, % of total intracellular lipid on cellbiomass
- PL/d, lipid production per day
- RI, refractive index
- RSM, response surface methodology
- Response surface methodology
- Rpm, revolutions per minute
- SD, stranded driftwood
- SE, steam explosion
- SFA, saturated fatty acid
- SL, solid loading
- Solicoccozyma terricola
- Stranded driftwood feedstocks
- TAGs, Tryacylglicerols
- UFA, unsaturated fatty acid
- UI, unsaturation index
- WIS, water insoluble substrate
- XG, Xilose and Galactose
- YL, lipid yied
- YPD, Yeast Extract Peptone Dextrose
- Yeast biochemicals and biofuels
- Yoleic, oleic acid yield
- g, gravity force
- h, hours
- min, minutes
- p, p-value
- v/v, concentration in volume/volume percent
- Δ13C22:1, erucic acid [(13Z)-docos-13-enoic acid]
- Δ9,12,15C18:3, linolenic acid [(9Z,12Z,15Z)-9,12,15-octadecatrienoic acid]
- Δ9,12C18:2, linoleic acid [(9Z,12Z)-9,12-octadecadienoic acid]
- Δ9C16:1, palmitoleic acid [(9Z)-hexadec-9-enoic acid]
- Δ9C18:1, oleic acid [(9E9Z)-octadec-9-enoic acid]
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Affiliation(s)
- Giorgia Tasselli
- Department of Agricultural, Food and Environmental Sciences, Industrial Yeasts Collection DBVPG, University of Perugia, Italy.,CIRIAF - Biomass Research Centre, University of Perugia, Italy
| | - Sara Filippucci
- Department of Agricultural, Food and Environmental Sciences, Industrial Yeasts Collection DBVPG, University of Perugia, Italy
| | | | - Gianluca Cavalaglio
- CIRIAF - Biomass Research Centre, University of Perugia, Italy.,Department of Engineering, University of Perugia, Italy
| | - Benedetta Turchetti
- Department of Agricultural, Food and Environmental Sciences, Industrial Yeasts Collection DBVPG, University of Perugia, Italy
| | - Franco Cotana
- CIRIAF - Biomass Research Centre, University of Perugia, Italy.,Department of Engineering, University of Perugia, Italy
| | - Pietro Buzzini
- Department of Agricultural, Food and Environmental Sciences, Industrial Yeasts Collection DBVPG, University of Perugia, Italy.,CIRIAF - Biomass Research Centre, University of Perugia, Italy
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Fahmy M, Sohel MI, Vaidya AA, Jack MW, Suckling ID. Does sugar yield drive lignocellulosic sugar cost? Case study for enzymatic hydrolysis of softwood with added polyethylene glycol. Process Biochem 2019. [DOI: 10.1016/j.procbio.2019.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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12
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Techno-economic evaluation of heat integrated second generation bioethanol and furfural coproduction. Biochem Eng J 2019. [DOI: 10.1016/j.bej.2019.01.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Application of electro-membrane separation for recovery of acetic acid in lignocellulosic bioethanol production. FOOD AND BIOPRODUCTS PROCESSING 2018. [DOI: 10.1016/j.fbp.2018.02.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Properties important for solid-liquid separations change during the enzymatic hydrolysis of pretreated wheat straw. Biotechnol Lett 2018; 40:703-709. [PMID: 29392453 DOI: 10.1007/s10529-018-2521-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 01/24/2018] [Indexed: 10/18/2022]
Abstract
OBJECTIVES The biochemical conversion of lignocellulosic biomass into renewable fuels and chemicals provides new challenges for industrial scale processes. One such process, which has received little attention, but is of great importance for efficient product recovery, is solid-liquid separations, which may occur both after pretreatment and after the enzymatic hydrolysis steps. Due to the changing nature of the solid biomass during processing, the solid-liquid separation properties of the biomass can also change. The objective of this study was to show the effect of enzymatic hydrolysis of cellulose upon the water retention properties of pretreated biomass over the course of the hydrolysis reaction. RESULTS Water retention value measurements, coupled with 1H NMR T2 relaxometry data, showed an increase in water retention and constraint of water by the biomass with increasing levels of cellulose hydrolysis. This correlated with an increase in the fines fraction and a decrease in particle size, suggesting that structural decomposition rather than changes in chemical composition was the most dominant characteristic. CONCLUSIONS With increased water retained by the insoluble fraction as cellulose hydrolysis proceeds, it may prove more difficult to efficiently separate hydrolysis residues from the liquid fraction with improved hydrolysis.
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15
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Liu G, Bao J. Maximizing cellulosic ethanol potentials by minimizing wastewater generation and energy consumption: Competing with corn ethanol. BIORESOURCE TECHNOLOGY 2017; 245:18-26. [PMID: 28892688 DOI: 10.1016/j.biortech.2017.08.070] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 08/11/2017] [Accepted: 08/12/2017] [Indexed: 06/07/2023]
Abstract
Energy consumption and wastewater generation in cellulosic ethanol production are among the determinant factors on overall cost and technology penetration into fuel ethanol industry. This study analyzed the energy consumption and wastewater generation by the new biorefining process technology, dry acid pretreatment and biodetoxification (DryPB), as well as by the current mainstream technologies. DryPB minimizes the steam consumption to 8.63GJ and wastewater generation to 7.71tons in the core steps of biorefining process for production of one metric ton of ethanol, close to 7.83GJ and 8.33tons in corn ethanol production, respectively. The relatively higher electricity consumption is compensated by large electricity surplus from lignin residue combustion. The minimum ethanol selling price (MESP) by DryPB is below $2/gal and falls into the range of corn ethanol production cost. The work indicates that the technical and economical gap between cellulosic ethanol and corn ethanol has been almost filled up.
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Affiliation(s)
- Gang Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
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16
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Mika LT, Cséfalvay E, Németh Á. Catalytic Conversion of Carbohydrates to Initial Platform Chemicals: Chemistry and Sustainability. Chem Rev 2017; 118:505-613. [DOI: 10.1021/acs.chemrev.7b00395] [Citation(s) in RCA: 662] [Impact Index Per Article: 94.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- László T. Mika
- Department
of Chemical and Environmental Process Engineering, Budapest University of Technology and Economics, Műegyetem rkp. 3., Budapest 1111, Hungary
| | - Edit Cséfalvay
- Department
of Energy Engineering, Budapest University of Technology and Economics, Budapest 1111, Hungary
| | - Áron Németh
- Department
of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, Budapest 1111, Hungary
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17
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Liu G, Zhang Q, Li H, Qureshi AS, Zhang J, Bao X, Bao J. Dry biorefining maximizes the potentials of simultaneous saccharification and co-fermentation for cellulosic ethanol production. Biotechnol Bioeng 2017; 115:60-69. [DOI: 10.1002/bit.26444] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 08/22/2017] [Accepted: 08/28/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Gang Liu
- State Key Laboratory of Bioreactor Engineering; East China University of Science and Technology; Shanghai China
| | - Qiang Zhang
- State Key Laboratory of Bioreactor Engineering; East China University of Science and Technology; Shanghai China
| | - Hongxing Li
- Shandong Provincial Key Laboratory of Microbial Engineering, Department of Bioengineering; Qilu University of Technology; Shandong China
| | - Abdul S. Qureshi
- State Key Laboratory of Bioreactor Engineering; East China University of Science and Technology; Shanghai China
| | - Jian Zhang
- State Key Laboratory of Bioreactor Engineering; East China University of Science and Technology; Shanghai China
| | - Xiaoming Bao
- State Key Laboratory of Microbial Technology, School of Life Science; Shandong University; Shandong China
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering; East China University of Science and Technology; Shanghai China
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18
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Loman AA, Islam SMM, Li Q, Ju LK. Enzyme recycle and fed-batch addition for high-productivity soybean flour processing to produce enriched soy protein and concentrated hydrolysate of fermentable sugars. BIORESOURCE TECHNOLOGY 2017; 241:252-261. [PMID: 28575788 DOI: 10.1016/j.biortech.2017.05.118] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/17/2017] [Accepted: 05/18/2017] [Indexed: 06/07/2023]
Abstract
Despite having high protein and carbohydrate, soybean flour utilization is limited to partial replacement of animal feed to date. Enzymatic process can be exploited to increase its value by enriching protein content and separating carbohydrate for utilization as fermentation feedstock. Enzyme hydrolysis with fed-batch and recycle designs were evaluated here for achieving this goal with high productivities. Fed-batch process improved carbohydrate conversion, particularly at high substrate loadings of 250-375g/L. In recycle process, hydrolysate retained a significant portion of the limiting enzyme α-galactosidase to accelerate carbohydrate monomerization rate. At single-pass retention time of 6h and recycle rate of 62.5%, reducing sugar concentration reached up to 120g/L using 4ml/g enzyme. When compared with batch and fed-batch processes, the recycle process increased the volumetric productivity of reducing sugar by 36% (vs. fed-batch) to 57% (vs. batch) and that of protein product by 280% (vs. fed-batch) to 300% (vs. batch).
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Affiliation(s)
- Abdullah Al Loman
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325-3906, USA
| | - S M Mahfuzul Islam
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325-3906, USA
| | - Qian Li
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325-3906, USA
| | - Lu-Kwang Ju
- Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, OH 44325-3906, USA.
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19
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Thompson RA, Trinh CT. Overflow metabolism and growth cessation in Clostridium thermocellum DSM1313 during high cellulose loading fermentations. Biotechnol Bioeng 2017; 114:2592-2604. [PMID: 28671264 DOI: 10.1002/bit.26374] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/25/2017] [Accepted: 06/27/2017] [Indexed: 12/31/2022]
Abstract
As a model thermophilic bacterium for the production of second-generation biofuels, the metabolism of Clostridium thermocellum has been widely studied. However, most studies have characterized C. thermocellum metabolism for growth at relatively low substrate concentrations. This outlook is not industrially relevant, however, as commercial viability requires substrate loadings of at least 100 g/L cellulosic materials. Recently, a wild-type C. thermocellum DSM1313 was cultured on high cellulose loading batch fermentations and reported to produce a wide range of fermentative products not seen at lower substrate concentrations, opening the door for a more in-depth analysis of how this organism will behave in industrially relevant conditions. In this work, we elucidated the interconnectedness of overflow metabolism and growth cessation in C. thermocellum during high cellulose loading batch fermentations (100 g/L). Metabolic flux and thermodynamic analyses suggested that hydrogen and formate accumulation perturbed the complex redox metabolism and limited conversion of pyruvate to acetyl-CoA conversion, likely leading to overflow metabolism and growth cessation in C. thermocellum. Pyruvate formate lyase (PFL) acts as an important redox valve and its flux is inhibited by formate accumulation. Finally, we demonstrated that manipulation of fermentation conditions to alleviate hydrogen accumulation could dramatically alter the fate of pyruvate, providing valuable insight into process design for enhanced C. thermocellum production of chemicals and biofuels. Biotechnol. Bioeng. 2017;114: 2592-2604. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- R Adam Thompson
- Bredesen Center for Interdisciplinary Research and Graduate Education, The University of Tennessee, Knoxville and Oak Ridge National Laboratory, Oak Ridge, Tennessee.,BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Cong T Trinh
- Bredesen Center for Interdisciplinary Research and Graduate Education, The University of Tennessee, Knoxville and Oak Ridge National Laboratory, Oak Ridge, Tennessee.,BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee.,Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, Tennessee
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20
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Krasznai DJ, Champagne Hartley R, Roy HM, Champagne P, Cunningham MF. Compositional analysis of lignocellulosic biomass: conventional methodologies and future outlook. Crit Rev Biotechnol 2017; 38:199-217. [PMID: 28595468 DOI: 10.1080/07388551.2017.1331336] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The composition and structural properties of lignocellulosic biomass have significant effects on its downstream conversion to fuels, biomaterials, and building-block chemicals. Specifically, the recalcitrance to modification and compositional variability of lignocellulose make it challenging to optimize and control the conditions under which the conversion takes place. Various characterization protocols have been developed over the past 150 years to elucidate the structural properties and compositional patterns that affect the processing of lignocellulose. Early characterization techniques were developed to estimate the relative digestibility and nutritional value of plant material after ingestion by ruminants and humans alike (e.g. dietary fiber). Over the years, these empirical techniques have evolved into statistical approaches that give a broader and more informative analysis of lignocellulose for conversion processes, to the point where an entire compositional and structural analysis of lignocellulosic biomass can be completed in minutes, rather than weeks. The use of modern spectroscopy and chemometric techniques has shown promise as a rapid and cost effective alternative to traditional empirical techniques. This review serves as an overview of the compositional analysis techniques that have been developed for lignocellulosic biomass in an effort to highlight the motivation and migration towards rapid, accurate, and cost-effective data-driven chemometric methods. These rapid analysis techniques can potentially be used to optimize future biorefinery unit operations, where large quantities of lignocellulose are continually processed into products of high value.
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Affiliation(s)
- Daniel J Krasznai
- a Department of Chemical Engineering , Queen's University , Kingston , Ontario , Canada
| | | | - Hannah M Roy
- b Department of Civil Engineering & Department of Chemical Engineering , Queen's University , Kingston , Ontario , Canada
| | - Pascale Champagne
- a Department of Chemical Engineering , Queen's University , Kingston , Ontario , Canada
| | - Michael F Cunningham
- a Department of Chemical Engineering , Queen's University , Kingston , Ontario , Canada
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21
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M. S, Singh S, Tiwari R, Goel R, Nain L. Do cultural conditions induce differential protein expression: Profiling of extracellular proteome of Aspergillus terreus CM20. Microbiol Res 2016; 192:73-83. [DOI: 10.1016/j.micres.2016.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 06/07/2016] [Accepted: 06/17/2016] [Indexed: 11/29/2022]
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22
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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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23
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Thompson RA, Dahal S, Garcia S, Nookaew I, Trinh CT. Exploring complex cellular phenotypes and model-guided strain design with a novel genome-scale metabolic model of Clostridium thermocellum DSM 1313 implementing an adjustable cellulosome. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:194. [PMID: 27602057 PMCID: PMC5012057 DOI: 10.1186/s13068-016-0607-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 08/26/2016] [Indexed: 05/06/2023]
Abstract
BACKGROUND Clostridium thermocellum is a gram-positive thermophile that can directly convert lignocellulosic material into biofuels. The metabolism of C. thermocellum contains many branches and redundancies which limit biofuel production, and typical genetic techniques are time-consuming. Further, the genome sequence of a genetically tractable strain C. thermocellum DSM 1313 has been recently sequenced and annotated. Therefore, developing a comprehensive, predictive, genome-scale metabolic model of DSM 1313 is desired for elucidating its complex phenotypes and facilitating model-guided metabolic engineering. RESULTS We constructed a genome-scale metabolic model iAT601 for DSM 1313 using the KEGG database as a scaffold and an extensive literature review and bioinformatic analysis for model refinement. Next, we used several sets of experimental data to train the model, e.g., estimation of the ATP requirement for growth-associated maintenance (13.5 mmol ATP/g DCW/h) and cellulosome synthesis (57 mmol ATP/g cellulosome/h). Using our tuned model, we investigated the effect of cellodextrin lengths on cell yields, and could predict in silico experimentally observed differences in cell yield based on which cellodextrin species is assimilated. We further employed our tuned model to analyze the experimentally observed differences in fermentation profiles (i.e., the ethanol to acetate ratio) between cellobiose- and cellulose-grown cultures and infer regulatory mechanisms to explain the phenotypic differences. Finally, we used the model to design over 250 genetic modification strategies with the potential to optimize ethanol production, 6155 for hydrogen production, and 28 for isobutanol production. CONCLUSIONS Our developed genome-scale model iAT601 is capable of accurately predicting complex cellular phenotypes under a variety of conditions and serves as a high-quality platform for model-guided strain design and metabolic engineering to produce industrial biofuels and chemicals of interest.
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Affiliation(s)
- R. Adam Thompson
- Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, TN 37996 USA
- Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Sanjeev Dahal
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Comparative Genomics Group, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
| | - Sergio Garcia
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Department of Chemical and Biomolecular Engineering, University of Tennessee, 1512 Middle Dr., DO#432, Knoxville, TN 37996 USA
| | - Intawat Nookaew
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Comparative Genomics Group, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Department of Biomedical Informatics, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205 USA
| | - Cong T. Trinh
- Bredesen Center for Interdisciplinary Research and Graduate Education, University of Tennessee, Knoxville, TN 37996 USA
- Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, TN 37831 USA
- Department of Chemical and Biomolecular Engineering, University of Tennessee, 1512 Middle Dr., DO#432, Knoxville, TN 37996 USA
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24
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Aghazadeh M, Engelberth AS. Techno-economic analysis for incorporating a liquid-liquid extraction system to remove acetic acid into a proposed commercial scale biorefinery. Biotechnol Prog 2016; 32:971-7. [PMID: 27390294 DOI: 10.1002/btpr.2325] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 06/28/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Mahdieh Aghazadeh
- Laboratory of Renewable Resources Engineering; Purdue University; West Lafayette IN 47907
- Dept. of Agricultural and Biological Engineering; Purdue University; West Lafayette IN 47907
| | - Abigail S. Engelberth
- Laboratory of Renewable Resources Engineering; Purdue University; West Lafayette IN 47907
- Dept. of Agricultural and Biological Engineering; Purdue University; West Lafayette IN 47907
- Div. of Environmental and Ecological Engineering; Purdue University; West Lafayette IN 47907
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25
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Svensson E, Lundberg V, Jansson M, Xiros C, Berntsson T. The effect of high solids loading in ethanol production integrated with a pulp mill. Chem Eng Res Des 2016. [DOI: 10.1016/j.cherd.2016.05.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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26
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Aghazadeh M, Ladisch MR, Engelberth AS. Acetic acid removal from corn stover hydrolysate using ethyl acetate and the impact onSaccharomyces cerevisiaebioethanol fermentation. Biotechnol Prog 2016; 32:929-37. [PMID: 27090191 DOI: 10.1002/btpr.2282] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 04/08/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Mahdieh Aghazadeh
- Laboratory of Renewable Resources Engineering; Purdue University; West Lafayette IN 47907
- Dept. of Agricultural and Biological Engineering; Purdue University; West Lafayette IN 47907
| | - Michael R. Ladisch
- Laboratory of Renewable Resources Engineering; Purdue University; West Lafayette IN 47907
- Dept. of Agricultural and Biological Engineering; Purdue University; West Lafayette IN 47907
- Weldon School of Biomedical Engineering; Purdue University; West Lafayette IN 47907
| | - Abigail S. Engelberth
- Laboratory of Renewable Resources Engineering; Purdue University; West Lafayette IN 47907
- Dept. of Agricultural and Biological Engineering; Purdue University; West Lafayette IN 47907
- Div. of Environmental and Ecological Engineering; Purdue University; West Lafayette IN 47907
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27
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Nwaneshiudu IC, Ganguly I, Pierobon F, Bowers T, Eastin I. Environmental assessment of mild bisulfite pretreatment of forest residues into fermentable sugars for biofuel production. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:15. [PMID: 26807148 PMCID: PMC4722614 DOI: 10.1186/s13068-016-0433-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 01/08/2016] [Indexed: 05/24/2023]
Abstract
BACKGROUND Sugar production via pretreatment and enzymatic hydrolysis of cellulosic feedstock, in this case softwood harvest residues, is a critical step in the biochemical conversion pathway towards drop-in biofuels. Mild bisulfite (MBS) pretreatment is an emerging option for the breakdown and subsequent processing of biomass towards fermentable sugars. An environmental assessment of this process is critical to discern its future sustainability in the ever-changing biofuels landscape. RESULTS The subsequent cradle-to-gate assessment of a proposed sugar production facility analyzes sugar made from woody biomass using MBS pretreatment across all seven impact categories (functional unit 1 kg dry mass sugar), with a specific focus on potential global warming and eutrophication impacts. The study found that the eutrophication impact (0.000201 kg N equivalent) is less than the impacts from conventional beet and cane sugars, while the global warming impact (0.353 kg CO2 equivalent) falls within the range of conventional processes. CONCLUSIONS This work discusses some of the environmental impacts of designing and operating a sugar production facility that uses MBS as a method of treating cellulosic forest residuals. The impacts of each unit process in the proposed facility are highlighted. A comparison to other sugar-making process is detailed and will inform the growing biofuels literature.
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Affiliation(s)
- Ikechukwu C. Nwaneshiudu
- Department of the Environment and Forest Sciences, University of Washington, Box 351750, Seattle, WA 98195 1750 USA
| | - Indroneil Ganguly
- Department of the Environment and Forest Sciences, University of Washington, Box 351750, Seattle, WA 98195 1750 USA
| | - Francesca Pierobon
- Department of the Environment and Forest Sciences, University of Washington, Box 351750, Seattle, WA 98195 1750 USA
| | - Tait Bowers
- Department of the Environment and Forest Sciences, University of Washington, Box 351750, Seattle, WA 98195 1750 USA
| | - Ivan Eastin
- Department of the Environment and Forest Sciences, University of Washington, Box 351750, Seattle, WA 98195 1750 USA
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28
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Fei Q, O’Brien M, Nelson R, Chen X, Lowell A, Dowe N. Enhanced lipid production by Rhodosporidium toruloides using different fed-batch feeding strategies with lignocellulosic hydrolysate as the sole carbon source. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:130. [PMID: 27340432 PMCID: PMC4918137 DOI: 10.1186/s13068-016-0542-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 06/02/2016] [Indexed: 05/15/2023]
Abstract
BACKGROUND Industrial biotechnology that is able to provide environmentally friendly bio-based products has attracted more attention in replacing petroleum-based industries. Currently, most of the carbon sources used for fermentation-based bioprocesses are obtained from agricultural commodities that are used as foodstuff for human beings. Lignocellulose-derived sugars as the non-food, green, and sustainable alternative carbon sources have great potential to avoid this dilemma for producing the renewable, bio-based hydrocarbon fuel precursors, such as microbial lipid. Efficient bioconversion of lignocellulose-based sugars into lipids is one of the critical parameters for industrial application. Therefore, the fed-batch cultivation, which is a common method used in industrial applications, was investigated to achieve a high cell density culture along with high lipid yield and productivity. RESULTS In this study, several fed-batch strategies were explored to improve lipid production using lignocellulosic hydrolysates derived from corn stover. Compared to the batch culture giving a lipid yield of 0.19 g/g, the dissolved-oxygen-stat feeding mode increased the lipid yield to 0.23 g/g and the lipid productivity to 0.33 g/L/h. The pulse feeding mode further improved lipid productivity to 0.35 g/L/h and the yield to 0.24 g/g. However, the highest lipid yield (0.29 g/g) and productivity (0.4 g/L/h) were achieved using an automated online sugar control feeding mode, which gave a dry cell weight of 54 g/L and lipid content of 59 % (w/w). The major fatty acids of the lipid derived from lignocellulosic hydrolysates were predominately palmitic acid and oleic acid, which are similar to those of conventional oilseed plants. CONCLUSIONS Our results suggest that the fed-batch feeding strategy can strongly influence the lipid production. The online sugar control feeding mode was the most appealing strategy for high cell density, lipid yield, and lipid productivity using lignocellulosic hydrolysates as the sole carbon source.
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Affiliation(s)
- Qiang Fei
- />School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an, 710049 China
- />National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401 USA
| | - Marykate O’Brien
- />National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401 USA
| | - Robert Nelson
- />National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401 USA
| | - Xiaowen Chen
- />National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401 USA
| | - Andrew Lowell
- />National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401 USA
- />KBI Biopharma, 2500 Central Ave, Boulder, CO 80301 USA
| | - Nancy Dowe
- />National Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, CO 80401 USA
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29
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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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30
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Agrawal R, Satlewal A, Gaur R, Mathur A, Kumar R, Gupta RP, Tuli DK. Pilot scale pretreatment of wheat straw and comparative evaluation of commercial enzyme preparations for biomass saccharification and fermentation. Biochem Eng J 2015. [DOI: 10.1016/j.bej.2015.02.018] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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31
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Zoglowek M, Lübeck PS, Ahring BK, Lübeck M. Heterologous expression of cellobiohydrolases in filamentous fungi – An update on the current challenges, achievements and perspectives. Process Biochem 2015. [DOI: 10.1016/j.procbio.2014.12.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Chen X, Shekiro J, Pschorn T, Sabourin M, Tucker MP, Tao L. Techno-economic analysis of the deacetylation and disk refining process: characterizing the effect of refining energy and enzyme usage on minimum sugar selling price and minimum ethanol selling price. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:173. [PMID: 26516346 PMCID: PMC4625976 DOI: 10.1186/s13068-015-0358-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 10/14/2015] [Indexed: 05/20/2023]
Abstract
BACKGROUND A novel, highly efficient deacetylation and disk refining (DDR) process to liberate fermentable sugars from biomass was recently developed at the National Renewable Energy Laboratory (NREL). The DDR process consists of a mild, dilute alkaline deacetylation step followed by low-energy-consumption disk refining. The DDR corn stover substrates achieved high process sugar conversion yields, at low to modest enzyme loadings, and also produced high sugar concentration syrups at high initial insoluble solid loadings. The sugar syrups derived from corn stover are highly fermentable due to low concentrations of fermentation inhibitors. The objective of this work is to evaluate the economic feasibility of the DDR process through a techno-economic analysis (TEA). RESULTS A large array of experiments designed using a response surface methodology was carried out to investigate the two major cost-driven operational parameters of the novel DDR process: refining energy and enzyme loadings. The boundary conditions for refining energy (128-468 kWh/ODMT), cellulase (Novozyme's CTec3) loading (11.6-28.4 mg total protein/g of cellulose), and hemicellulase (Novozyme's HTec3) loading (0-5 mg total protein/g of cellulose) were chosen to cover the most commercially practical operating conditions. The sugar and ethanol yields were modeled with good adequacy, showing a positive linear correlation between those yields and refining energy and enzyme loadings. The ethanol yields ranged from 77 to 89 gallons/ODMT of corn stover. The minimum sugar selling price (MSSP) ranged from $0.191 to $0.212 per lb of 50 % concentrated monomeric sugars, while the minimum ethanol selling price (MESP) ranged from $2.24 to $2.54 per gallon of ethanol. CONCLUSIONS The DDR process concept is evaluated for economic feasibility through TEA. The MSSP and MESP of the DDR process falls within a range similar to that found with the deacetylation/dilute acid pretreatment process modeled in NREL's 2011 design report. The DDR process is a much simpler process that requires less capital and maintenance costs when compared to conventional chemical pretreatments with pressure vessels. As a result, we feel the DDR process should be considered as an option for future biorefineries with great potential to be more cost-effective.
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Affiliation(s)
- Xiaowen Chen
- />National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80127 USA
| | - Joseph Shekiro
- />National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80127 USA
| | - Thomas Pschorn
- />Andritz Inc., 3200 Upper Valley Pike, Springfield, OH USA
| | - Marc Sabourin
- />Andritz Inc., 3200 Upper Valley Pike, Springfield, OH USA
| | - Melvin P. Tucker
- />National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80127 USA
| | - Ling Tao
- />National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80127 USA
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Lei C, Zhang J, Xiao L, Bao J. An alternative feedstock of corn meal for industrial fuel ethanol production: delignified corncob residue. BIORESOURCE TECHNOLOGY 2014; 167:555-9. [PMID: 25027810 DOI: 10.1016/j.biortech.2014.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 06/01/2014] [Accepted: 06/03/2014] [Indexed: 05/23/2023]
Abstract
Delignified corncob residue is an industrial solid waste from xylose production using corncob as feedstock. In this study, delignified corncob residue was used as the feedstock of ethanol production by simultaneous saccharification and fermentation (SSF) and the optimal fermentation performance was investigated under various operation conditions. The ethanol titer and yield reached 75.07 g/L and 89.38%, respectively, using a regular industrial yeast strain at moderate cellulase dosage and high solids loading. A uniform SSF temperature of 37°C at both prehydrolysis and SSF stages was tested. The fermentation performance and cost of delignified corncob residue and corn meal was compared as feedstock of ethanol fermentation. The result shows that the delignified corncob residue is competitive to corn meal as ethanol production feedstock. The study gives a typical case to demonstrate the potential of intensively processed lignocellulose as the alternative feedstock of corn meal for industrial fuel ethanol production.
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Affiliation(s)
- Cheng Lei
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Jian Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China; Key Laboratory for Solid Waste Management and Environment Safety, Ministry of Education of China, Tsinghua University, Beijing 10084, China
| | - Lin Xiao
- Shandong Longlive Biotechnology Co., High-Tech Development Zone, Yucheng, Shandong 251200, China
| | - Jie Bao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
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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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Current challenges in commercially producing biofuels from lignocellulosic biomass. ISRN BIOTECHNOLOGY 2014; 2014:463074. [PMID: 25937989 PMCID: PMC4393053 DOI: 10.1155/2014/463074] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Accepted: 02/19/2014] [Indexed: 11/17/2022]
Abstract
Biofuels that are produced from biobased materials are a good alternative to petroleum based fuels. They offer several benefits to society and the environment. Producing second generation biofuels is even more challenging than producing first generation biofuels due the complexity of the biomass and issues related to producing, harvesting, and transporting less dense biomass to centralized biorefineries. In addition to this logistic challenge, other challenges with respect to processing steps in converting biomass to liquid transportation fuel like pretreatment, hydrolysis, microbial fermentation, and fuel separation still exist and are discussed in this review. The possible coproducts that could be produced in the biorefinery and their importance to reduce the processing cost of biofuel are discussed. About $1 billion was spent in the year 2012 by the government agencies in US to meet the mandate to replace 30% existing liquid transportation fuels by 2022 which is 36 billion gallons/year. Other countries in the world have set their own targets to replace petroleum fuel by biofuels. Because of the challenges listed in this review and lack of government policies to create the demand for biofuels, it may take more time for the lignocellulosic biofuels to hit the market place than previously projected.
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Palmqvist B, Lidén G. Combining the effects of process design and pH for improved xylose conversion in high solid ethanol production from Arundo donax. AMB Express 2014; 4:41. [PMID: 24949274 PMCID: PMC4052779 DOI: 10.1186/s13568-014-0041-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 04/01/2014] [Indexed: 11/10/2022] Open
Abstract
The impact of pH coupled to process design for the conversion of the energy crop Arundo donax to ethanol was assessed in the present study under industrially relevant solids loadings. Two main process strategies were investigated, i.e. the traditional simultaneous saccharification and co-fermentation (SSCF) and a HYBRID design, where a long high temperature enzymatic hydrolysis step was carried out prior to continued low temperature SSCF, keeping the same total reaction time. Since acetic acid was identified as the major inhibitor in the slurry, the scenarios were investigated under different fermentation pH in order to alleviate the inhibitory effect on, in particular, xylose conversion. The results show that, regardless of fermentation pH, a higher glucan conversion could be achieved with the HYBRID approach compared to SSCF. Furthermore, it was found that increasing the pH from 5.0 to 5.5 for the fermentation phase had a large positive effect on xylose consumption for both process designs, although the SSCF design was more favored. With the high sugar concentrations available at the start of fermentation during the HYBRID design, the ethanol yield was reduced in favor of cell growth and glycerol production. This finding was confirmed in shake flask fermentations where an increase in pH enhanced both glucose and xylose consumption, but also cell growth and cell yield with the overall effect being a reduced ethanol yield. In conclusion this resulted in similar overall ethanol yields at the different pH values for the HYBRID design, despite the improved xylose uptake, whereas a significant increase in overall ethanol yield was found with the SSCF design.
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Tozzi EJ, McCarthy MJ, Lavenson DM, Cardona M, Powell ARL, Karuna N, Jeoh T. Effect of fiber structure on yield stress during enzymatic conversion of cellulose. AIChE J 2014. [DOI: 10.1002/aic.14374] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Emilio J. Tozzi
- Dept. of Food Science and Technology; University of California, Davis; Davis CA 95616
| | - Michael J. McCarthy
- Dept. of Food Science and Technology; University of California, Davis; Davis CA 95616
| | - David M. Lavenson
- Dept. of Chemical Engineering and Materials Science; University of California, Davis; Davis CA 95616
| | - Maria Cardona
- Dept. of Chemical Engineering and Materials Science; University of California, Davis; Davis CA 95616
| | - and Robert L. Powell
- Dept. of Chemical Engineering and Materials Science; University of California, Davis; Davis CA 95616
| | - Nardrapee Karuna
- Dept. of Biological and Agricultural Engineering; University of California, Davis; Davis CA 95616
| | - Tina Jeoh
- Dept. of Biological and Agricultural Engineering; University of California, Davis; Davis CA 95616
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Holwerda EK, Thorne PG, Olson DG, Amador-Noguez D, Engle NL, Tschaplinski TJ, van Dijken JP, Lynd LR. The exometabolome of Clostridium thermocellum reveals overflow metabolism at high cellulose loading. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:155. [PMID: 25379055 PMCID: PMC4207885 DOI: 10.1186/s13068-014-0155-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 10/03/2014] [Indexed: 05/18/2023]
Abstract
BACKGROUND Clostridium thermocellum is a model thermophilic organism for the production of biofuels from lignocellulosic substrates. The majority of publications studying the physiology of this organism use substrate concentrations of ≤10 g/L. However, industrially relevant concentrations of substrate start at 100 g/L carbohydrate, which corresponds to approximately 150 g/L solids. To gain insight into the physiology of fermentation of high substrate concentrations, we studied the growth on, and utilization of high concentrations of crystalline cellulose varying from 50 to 100 g/L by C. thermocellum. RESULTS Using a defined medium, batch cultures of C. thermocellum achieved 93% conversion of cellulose (Avicel) initially present at 100 g/L. The maximum rate of substrate utilization increased with increasing substrate loading. During fermentation of 100 g/L cellulose, growth ceased when about half of the substrate had been solubilized. However, fermentation continued in an uncoupled mode until substrate utilization was almost complete. In addition to commonly reported fermentation products, amino acids - predominantly L-valine and L-alanine - were secreted at concentrations up to 7.5 g/L. Uncoupled metabolism was also accompanied by products not documented previously for C. thermocellum, including isobutanol, meso- and RR/SS-2,3-butanediol and trace amounts of 3-methyl-1-butanol, 2-methyl-1-butanol and 1-propanol. We hypothesize that C. thermocellum uses overflow metabolism to balance its metabolism around the pyruvate node in glycolysis. CONCLUSIONS C. thermocellum is able to utilize industrially relevant concentrations of cellulose, up to 93 g/L. We report here one of the highest degrees of crystalline cellulose utilization observed thus far for a pure culture of C. thermocellum, the highest maximum substrate utilization rate and the highest amount of isobutanol produced by a wild-type organism.
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Affiliation(s)
- Evert K Holwerda
- />Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
- />BioEnergy Science Center, Oak Ridge, TN 37830 USA
| | | | - Daniel G Olson
- />Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
- />BioEnergy Science Center, Oak Ridge, TN 37830 USA
| | - Daniel Amador-Noguez
- />Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706 USA
| | - Nancy L Engle
- />BioEnergy Science Center, Oak Ridge, TN 37830 USA
- />Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - Timothy J Tschaplinski
- />BioEnergy Science Center, Oak Ridge, TN 37830 USA
- />Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830 USA
| | - Johannes P van Dijken
- />Emeritus Industrial Biotechnology of Delft University of Technology, Delft, BC 2628 The Netherlands
| | - Lee R Lynd
- />Thayer School of Engineering, Dartmouth College, Hanover, NH 03755 USA
- />BioEnergy Science Center, Oak Ridge, TN 37830 USA
- />Mascoma Corporation, Lebanon, NH 03766 USA
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Ekwe E, Morgenstern I, Tsang A, Storms R, Powlowski J. Non-Hydrolytic Cellulose Active Proteins: Research Progress and Potential Application in Biorefineries. Ind Biotechnol (New Rochelle N Y) 2013. [DOI: 10.1089/ind.2013.0010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Enongene Ekwe
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada
| | - Ingo Morgenstern
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Adrian Tsang
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Reginald Storms
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
- Department of Biology, Concordia University, Montreal, Quebec, Canada
| | - Justin Powlowski
- Centre for Structural and Functional Genomics, Concordia University, Montreal, Quebec, Canada
- Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada
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Newman RH, Vaidya AA, Sohel MI, Jack MW. Optimizing the enzyme loading and incubation time in enzymatic hydrolysis of lignocellulosic substrates. BIORESOURCE TECHNOLOGY 2013; 129:33-8. [PMID: 23232221 DOI: 10.1016/j.biortech.2012.11.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 11/05/2012] [Accepted: 11/05/2012] [Indexed: 05/14/2023]
Abstract
A mathematical model for costing enzymatic hydrolysis of lignocellulosics is presented. This model is based on three variable parameters describing substrate characteristics and three unit costs for substrate, enzymes and incubation. The model is used to minimize the cost of fermentable sugars, as intermediate products on the route to ethanol or other biorefinery products, by calculating optimized values of enzyme loading and incubation time. This approach allows comparisons between substrates, with processing conditions optimized independently for each substrate. Steam-exploded pine wood was hydrolyzed in order to test the theoretical relationship between sugar yield and processing conditions.
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Affiliation(s)
- Roger H Newman
- Scion, Private Bag 3020, Rotorua Mail Centre, Rotorua 3046, New Zealand.
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Chen X, Tao L, Shekiro J, Mohaghaghi A, Decker S, Wang W, Smith H, Park S, Himmel ME, Tucker M. Improved ethanol yield and reduced Minimum Ethanol Selling Price (MESP) by modifying low severity dilute acid pretreatment with deacetylation and mechanical refining: 1) Experimental. BIOTECHNOLOGY FOR BIOFUELS 2012; 5:60. [PMID: 22888758 PMCID: PMC3519810 DOI: 10.1186/1754-6834-5-60] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 08/07/2012] [Indexed: 05/03/2023]
Abstract
BACKGROUND Historically, acid pretreatment technology for the production of bio-ethanol from corn stover has required severe conditions to overcome biomass recalcitrance. However, the high usage of acid and steam at severe pretreatment conditions hinders the economic feasibility of the ethanol production from biomass. In addition, the amount of acetate and furfural produced during harsh pretreatment is in the range that strongly inhibits cell growth and impedes ethanol fermentation. The current work addresses these issues through pretreatment with lower acid concentrations and temperatures incorporated with deacetylation and mechanical refining. RESULTS The results showed that deacetylation with 0.1 M NaOH before acid pretreatment improved the monomeric xylose yield in pretreatment by up to 20% while keeping the furfural yield under 2%. Deacetylation also improved the glucose yield by 10% and the xylose yield by 20% during low solids enzymatic hydrolysis. Mechanical refining using a PFI mill further improved sugar yields during both low- and high-solids enzymatic hydrolysis. Mechanical refining also allowed enzyme loadings to be reduced while maintaining high yields. Deacetylation and mechanical refining are shown to assist in achieving 90% cellulose yield in high-solids (20%) enzymatic hydrolysis. When fermentations were performed under pH control to evaluate the effect of deacetylation and mechanical refining on the ethanol yields, glucose and xylose utilizations over 90% and ethanol yields over 90% were achieved. Overall ethanol yields were calculated based on experimental results for the base case and modified cases. One modified case that integrated deacetylation, mechanical refining, and washing was estimated to produce 88 gallons of ethanol per ton of biomass. CONCLUSION The current work developed a novel bio-ethanol process that features pretreatment with lower acid concentrations and temperatures incorporated with deacetylation and mechanical refining. The new process shows improved overall ethanol yields compared to traditional dilute acid pretreatment. The experimental results from this work support the techno-economic analysis and calculation of Minimum Ethanol Selling Price (MESP) detailed in our companion paper.
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Affiliation(s)
- Xiaowen Chen
- National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO, 80127, USA
| | - Ling Tao
- National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO, 80127, USA
| | - Joseph Shekiro
- National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO, 80127, USA
| | - Ali Mohaghaghi
- National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO, 80127, USA
| | - Steve Decker
- Bioscience Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO, 80127, USA
| | - Wei Wang
- Bioscience Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO, 80127, USA
| | - Holly Smith
- National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO, 80127, USA
| | - Sunkyu Park
- Department of Forest Biomaterials, North Carolina State University, 2820 Faucette Drive, Raleigh, NC, 27695, USA
| | - Michael E Himmel
- Bioscience Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO, 80127, USA
| | - Melvin Tucker
- National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO, 80127, USA
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Bioprocessing for biofuels. Curr Opin Biotechnol 2012; 23:390-5. [DOI: 10.1016/j.copbio.2011.10.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 09/13/2011] [Accepted: 10/02/2011] [Indexed: 11/19/2022]
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Fox JM, Levine SE, Blanch HW, Clark DS. An evaluation of cellulose saccharification and fermentation with an engineered Saccharomyces cerevisiae capable of cellobiose and xylose utilization. Biotechnol J 2012; 7:361-73. [DOI: 10.1002/biot.201100209] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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44
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The adsorption and enzyme activity profiles of specific Trichoderma reesei cellulase/xylanase components when hydrolyzing steam pretreated corn stover. Enzyme Microb Technol 2012; 50:195-203. [DOI: 10.1016/j.enzmictec.2011.12.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Revised: 12/07/2011] [Accepted: 12/19/2011] [Indexed: 11/23/2022]
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Chen X, Shekiro J, Franden MA, Wang W, Zhang M, Kuhn E, Johnson DK, Tucker MP. The impacts of deacetylation prior to dilute acid pretreatment on the bioethanol process. BIOTECHNOLOGY FOR BIOFUELS 2012; 5:8. [PMID: 22369467 DOI: 10.1186/1754-6834-1185-1188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 02/27/2012] [Indexed: 05/28/2023]
Abstract
BACKGROUND Dilute acid pretreatment is a promising pretreatment technology for the biochemical production of ethanol from lignocellulosic biomass. During dilute acid pretreatment, xylan depolymerizes to form soluble xylose monomers and oligomers. Because the xylan found in nature is highly acetylated, the formation of xylose monomers requires two steps: 1) cleavage of the xylosidic bonds, and 2) cleavage of covalently bonded acetyl ester groups. RESULTS In this study, we show that the latter may be the rate limiting step for xylose monomer formation. Furthermore, acetyl groups are also found to be a cause of biomass recalcitrance and hydrolyzate toxicity. While the removal of acetyl groups from native corn stover by alkaline de-esterification prior to pretreatment improves overall process yields, the exact impact is highly dependent on the corn stover variety in use. Xylose monomer yields in pretreatment generally increases by greater than 10%. Compared to pretreated corn stover controls, the deacetylated corn stover feedstock is approximately 20% more digestible after pretreatment. Finally, by lowering hydrolyzate toxicity, xylose utilization and ethanol yields are further improved during fermentation by roughly 10% and 7%, respectively. In this study, several varieties of corn stover lots were investigated to test the robustness of the deacetylation-pretreatment-saccharification-fermentation process. CONCLUSIONS Deacetylation shows significant improvement on glucose and xylose yields during pretreatment and enzymatic hydrolysis, but it also reduces hydrolyzate toxicity during fermentation, thereby improving ethanol yields and titer. The magnitude of effect is dependent on the selected corn stover variety, with several varieties achieving improvements of greater than 10% xylose yield in pretreatment, 20% glucose yield in low solids enzymatic hydrolysis and 7% overall ethanol yield.
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Affiliation(s)
- Xiaowen Chen
- National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80127, USA.
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46
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Chen X, Shekiro J, Franden MA, Wang W, Zhang M, Kuhn E, Johnson DK, Tucker MP. The impacts of deacetylation prior to dilute acid pretreatment on the bioethanol process. BIOTECHNOLOGY FOR BIOFUELS 2012; 5:8. [PMID: 22369467 PMCID: PMC3309953 DOI: 10.1186/1754-6834-5-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 02/27/2012] [Indexed: 05/02/2023]
Abstract
BACKGROUND Dilute acid pretreatment is a promising pretreatment technology for the biochemical production of ethanol from lignocellulosic biomass. During dilute acid pretreatment, xylan depolymerizes to form soluble xylose monomers and oligomers. Because the xylan found in nature is highly acetylated, the formation of xylose monomers requires two steps: 1) cleavage of the xylosidic bonds, and 2) cleavage of covalently bonded acetyl ester groups. RESULTS In this study, we show that the latter may be the rate limiting step for xylose monomer formation. Furthermore, acetyl groups are also found to be a cause of biomass recalcitrance and hydrolyzate toxicity. While the removal of acetyl groups from native corn stover by alkaline de-esterification prior to pretreatment improves overall process yields, the exact impact is highly dependent on the corn stover variety in use. Xylose monomer yields in pretreatment generally increases by greater than 10%. Compared to pretreated corn stover controls, the deacetylated corn stover feedstock is approximately 20% more digestible after pretreatment. Finally, by lowering hydrolyzate toxicity, xylose utilization and ethanol yields are further improved during fermentation by roughly 10% and 7%, respectively. In this study, several varieties of corn stover lots were investigated to test the robustness of the deacetylation-pretreatment-saccharification-fermentation process. CONCLUSIONS Deacetylation shows significant improvement on glucose and xylose yields during pretreatment and enzymatic hydrolysis, but it also reduces hydrolyzate toxicity during fermentation, thereby improving ethanol yields and titer. The magnitude of effect is dependent on the selected corn stover variety, with several varieties achieving improvements of greater than 10% xylose yield in pretreatment, 20% glucose yield in low solids enzymatic hydrolysis and 7% overall ethanol yield.
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Affiliation(s)
- Xiaowen Chen
- National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80127, USA
| | - Joseph Shekiro
- National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80127, USA
| | - Mary Ann Franden
- National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80127, USA
| | - Wei Wang
- Biosciences Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80127, USA
| | - Min Zhang
- National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80127, USA
| | - Erik Kuhn
- National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80127, USA
| | - David K Johnson
- Biosciences Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80127, USA
| | - Melvin P Tucker
- National Bioenergy Center, National Renewable Energy Lab, 1617 Cole Blvd, Golden, CO 80127, USA
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McMillan JD, Jennings EW, Mohagheghi A, Zuccarello M. Comparative performance of precommercial cellulases hydrolyzing pretreated corn stover. BIOTECHNOLOGY FOR BIOFUELS 2011; 4:29. [PMID: 21899748 PMCID: PMC3200994 DOI: 10.1186/1754-6834-4-29] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 09/07/2011] [Indexed: 05/02/2023]
Abstract
BACKGROUND Cellulases and related hydrolytic enzymes represent a key cost factor for biochemical conversion of cellulosic biomass feedstocks to sugars for biofuels and chemicals production. The US Department of Energy (DOE) is cost sharing projects to decrease the cost of enzymes for biomass saccharification. The performance of benchmark cellulase preparations produced by Danisco, DSM, Novozymes and Verenium to convert pretreated corn stover (PCS) cellulose to glucose was evaluated under common experimental conditions and is reported here in a non-attributed manner. RESULTS Two hydrolysis modes were examined, enzymatic hydrolysis (EH) of PCS whole slurry or washed PCS solids at pH 5 and 50°C, and simultaneous saccharification and fermentation (SSF) of washed PCS solids at pH 5 and 38°C. Enzymes were dosed on a total protein mass basis, with protein quantified using both the bicinchoninic acid (BCA) assay and the Bradford assay. Substantial differences were observed in absolute cellulose to glucose conversion performance levels under the conditions tested. Higher cellulose conversion yields were obtained using washed solids compared to whole slurry, and estimated enzyme protein dosages required to achieve a particular cellulose conversion to glucose yield were extremely dependent on the protein assay used. All four enzyme systems achieved glucose yields of 90% of theoretical or higher in SSF mode. Glucose yields were reduced in EH mode, with all enzymes achieving glucose yields of at least 85% of theoretical on washed PCS solids and 75% in PCS whole slurry. One of the enzyme systems ('enzyme B') exhibited the best overall performance. However in attaining high conversion yields at lower total enzyme protein loadings, the relative and rank ordered performance of the enzyme systems varied significantly depending upon which hydrolysis mode and protein assay were used as the basis for comparison. CONCLUSIONS This study provides extensive information about the performance of four precommercial cellulase preparations. Though test conditions were not necessarily optimal for some of the enzymes, all were able to effectively saccharify PCS cellulose. Large differences in the estimated enzyme dosage requirements depending on the assay used to measure protein concentration highlight the need for better consensus methods to quantify enzyme protein.
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Affiliation(s)
- James D McMillan
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Edward W Jennings
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Ali Mohagheghi
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA
| | - Mildred Zuccarello
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO, USA
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