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Abstract
Fossil fuels are a major contributor to climate change, and as the demand for energy production increases, alternative sources (e.g., renewables) are becoming more attractive. Biofuels such as bioethanol reduce reliance on fossil fuels and can be compatible with the existing fleet of internal combustion engines. Incorporation of biofuels can reduce internal combustion engine (ICE) fleet carbon dioxide emissions. Bioethanol is typically produced via microbial fermentation of fermentable sugars, such as glucose, to ethanol. Traditional feedstocks (e.g., first-generation feedstock) include cereal grains, sugar cane, and sugar beets. However, due to concerns regarding food sustainability, lignocellulosic (second-generation) and algal biomass (third-generation) feedstocks have been investigated. Ethanol yield from fermentation is dependent on a multitude of factors. This review compares bioethanol production from a range of feedstocks, and elaborates on available technologies, including fermentation practices. The importance of maintaining nutrient homeostasis of yeast is also examined. The purpose of this review is to provide industrial producers and policy makers insight into available technologies, yields of bioethanol achieved by current manufacturing practices, and goals for future innovation.
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Reungoat V, Mouterde LM, Chadni M, Couvreur J, Isidore E, Allais F, Ducatel H, Ioannou I. Simultaneous extraction and enzymatic hydrolysis of mustard bran for the recovery of sinapic acid. FOOD AND BIOPRODUCTS PROCESSING 2021. [DOI: 10.1016/j.fbp.2021.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Li J, Shi S, Wang Y, Jiang Z. Integrated production of optically pure l-lactic acid from paper mill sludge by simultaneous saccharification and co-fermentation (SSCF). WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 129:35-46. [PMID: 34023801 DOI: 10.1016/j.wasman.2021.05.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Revised: 05/05/2021] [Accepted: 05/06/2021] [Indexed: 06/12/2023]
Abstract
Paper mill sludge (PMS) raises critical environmental issues due to its disposal problem, but its high sugar content and well-dispersed structure make it a great feedstock for biochemical production. The technical feasibility of integrating cellulase enzyme production into lactic acid (LA) fermentation from PMS was investigated in this study. The low ash content of PMS suggests a great potential for cellulase production. The enzyme produced using PMS without any treatment gave an activity of 7.8 FPU/ml, a performance comparable to the commercial enzyme, Cellic CTec 2. The LA yield from PMS with in-house enzyme was 64.7% and 73.7% at the enzyme loading of 10 and 15 FPU/g-glucan, respectively. The LA obtained was optically pure L- isomer with over 99% purity. The optimal condition of LA production by Bacillus coagulans was found to be 50 °C and pH 5.3 (with 50 g/L CaCO3). The nutrient effect of yeast extract (YE) and corn steep liquor (CSL) was substrate dependent, and CSL could substitute YE as an inexpensive nutrient when using PMS as a substrate.
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Affiliation(s)
- Jing Li
- Alabama Center for Paper and Bioresource Engineering, Department of Chemical Engineering, Auburn University, Auburn, AL 36849, United States
| | - Suan Shi
- Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, United States
| | - Yi Wang
- Department of Biosystems Engineering, Auburn University, Auburn, AL 36849, United States
| | - Zhihua Jiang
- Alabama Center for Paper and Bioresource Engineering, Department of Chemical Engineering, Auburn University, Auburn, AL 36849, United States.
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Lignocellulosic bioethanol production from grasses pre-treated with acid mine drainage: Modeling and comparison of SHF and SSF. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2019.100299] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Motte JC, Watteau F, Escudié R, Steyer JP, Bernet N, Delgenes JP, Dumas C. Dynamic observation of the biodegradation of lignocellulosic tissue under solid-state anaerobic conditions. BIORESOURCE TECHNOLOGY 2015; 191:322-326. [PMID: 26026233 DOI: 10.1016/j.biortech.2015.04.130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 04/29/2015] [Accepted: 04/30/2015] [Indexed: 06/04/2023]
Abstract
The solid-state anaerobic digestion (SS-AD) of wheat straw was characterized under low inoculated batch tests during 244 days. High levels of degradation of the cellulose (52%±1) and hemicelluloses (55%±2) were observed at the final stages and associated to a methane yield of 204±16 NmL gTS(-1). Ultrastructural observations, using transmission electronic microscopy, indicated that microorganisms degraded wheat straw from the central to the outer tissue (i.e. parenchyma to epidermis), depending on cell chemical, physical accessibility and the degree of lignification. Furthermore, major degradation of sclerenchyma secondary walls was observed. The bioaccessibility of lignocellulosic structures of wheat straw is mainly limited by the external waxy layer (cuticle), tertiary cell walls, high silica content and access to the cell lumen.
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Affiliation(s)
- J-C Motte
- INRA, UR0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, Narbonne F-11100, France
| | - F Watteau
- Université de Lorraine, LSE, UMR 1120, Vandœuvre-lès-Nancy F-54505, France; CNRS, UMS 3562, Vandœuvre-lès-Nancy F-54501, France
| | - R Escudié
- INRA, UR0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, Narbonne F-11100, France
| | - J-P Steyer
- INRA, UR0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, Narbonne F-11100, France
| | - N Bernet
- INRA, UR0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, Narbonne F-11100, France
| | - J-P Delgenes
- INRA, UR0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, Narbonne F-11100, France
| | - C Dumas
- INRA, UR0050, Laboratoire de Biotechnologie de l'Environnement, Avenue des Etangs, Narbonne F-11100, France; LISBP - INSA de Toulouse, INSA/CNRS 5504 - UMR INSA/INRA 792, 135 Avenue de Rangueil, 31077 Toulouse CEDEX 04, France.
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El-Ahmady N, Deraz S, Khalil A. Bioethanol Production from Lignocellulosic Feedstocks Based on Enzymatic Hydrolysis:
Current Status and Recent Developments. ACTA ACUST UNITED AC 2013. [DOI: 10.3923/biotech.2014.1.21] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Lee JY, Li P, Lee J, Ryu HJ, Oh KK. Ethanol production from Saccharina japonica using an optimized extremely low acid pretreatment followed by simultaneous saccharification and fermentation. BIORESOURCE TECHNOLOGY 2013; 127:119-25. [PMID: 23131631 DOI: 10.1016/j.biortech.2012.09.122] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2012] [Revised: 08/24/2012] [Accepted: 09/28/2012] [Indexed: 05/23/2023]
Abstract
An extremely low acid (ELA) pretreatment using 0.06% (w/w) sulfuric acid at 170 °C for 15 min was employed to extract non-glucan components from Saccharina japonica, a brown macroalgae. Subsequent simultaneous saccharification and fermentation (SSF) was conducted using Saccharomyces cerevisiae DK 410362 and cellulase (15 FPU/g-glucan) and ß-glucosidase (70 pNPGU/g-glucan). Deionized water was used for making fermentation suspension. After the ELA pretreatment, a glucan content of 29.10% and an enzymatic digestibility of 83.96% was obtained for pretreated S. japonica. These values are 4.2- and 2.4-fold higher, respectively, than those of obtained with untreated S. japonica. In SSF, a bioethanol concentration of 6.65 g/L was obtained, corresponding to a glucose equivalent concentration of 13.01 g/L, which indicated an SSF yield of 67.41% based on the total available glucan of the pretreated S. japonica. The remaining separated liquid hydrolysate, which contains mannitol and alginate-derived oligosaccharides can be applied to other fermentations.
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Affiliation(s)
- Ji ye Lee
- Department of Applied Chemical Engineering, Dankook University, Cheonan, Chungnam 330-714, South Korea
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Producing bioethanol from cellulosic hydrolyzate via co-immobilized cultivation strategy. J Biosci Bioeng 2012; 114:198-203. [DOI: 10.1016/j.jbiosc.2012.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 03/16/2012] [Accepted: 03/17/2012] [Indexed: 11/20/2022]
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9
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Won KY, Kim YS, Oh KK. Comparison of bioethanol production of simultaneous saccharification & fermentation and separation hydrolysis & fermentation from cellulose-rich barley straw. KOREAN J CHEM ENG 2012. [DOI: 10.1007/s11814-012-0019-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Vimala Rodhe A, Sateesh L, Sridevi J, Venkateswarlu B, Venkateswar Rao L. Enzymatic hydrolysis of sorghum straw using native cellulase produced by T. reesei NCIM 992 under solid state fermentation using rice straw. 3 Biotech 2011; 1:207-215. [PMID: 22558539 PMCID: PMC3339599 DOI: 10.1007/s13205-011-0024-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Accepted: 09/06/2011] [Indexed: 11/26/2022] Open
Abstract
Cellulose is a major constituent of renewable lignocellulosic waste available in large quantities and is considered the most important reservoir of carbon for the production of glucose, for alternative fuel and as a chemical feedstock. Over the past decade, the emphasis has been on the enzymatic hydrolysis of cellulose to glucose and the efficiency of which depends on source of cellulosic substrate, its composition, structure, pretreatment process, and reactor design. In the present study, efforts were made to produce cellulase enzyme using rice straw. The produced enzyme was used for the hydrolysis of selected lignocellulosic substrate, i.e., sorghum straw. When rice straw was used as a substrate for cellulase production under solid state fermentation, the highest enzyme activity obtained was 30.7 FPU/gds, using T. reesei NCIM 992. 25 FPU/g of cellulase was added to differently treated (native, alkali treated, alkali treated followed by 3% acid treated and alkali treated followed by 3 and 5% acid treated) sorghum straw and hydrolysis was carried out at 50 °C for 60 h. 42.5% hydrolysis was obtained after 36 h of incubation. Optimization of enzyme loading, substrate concentration, temperature, time and buffer yielded a maximum of 546.00 ± 0.55 mg/g sugars (54.60 ± 0.44 g/l) with an improved hydrolysis efficiency of 70 ± 0.45%. The enzymatic hydrolyzate can be used for fermentation of ethanol by yeasts.
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Affiliation(s)
- A. Vimala Rodhe
- Department of Microbiology, UCS, Osmania University, Hyderabad, India
| | - L. Sateesh
- Department of Microbiology, UCS, Osmania University, Hyderabad, India
| | - J. Sridevi
- Department of Microbiology, UCS, Osmania University, Hyderabad, India
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Kim JH, Lee JC, Pak D. Feasibility of producing ethanol from food waste. WASTE MANAGEMENT (NEW YORK, N.Y.) 2011; 31:2121-5. [PMID: 21596551 DOI: 10.1016/j.wasman.2011.04.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 04/04/2011] [Accepted: 04/16/2011] [Indexed: 05/23/2023]
Abstract
Food waste generated in Korea is rich in carbohydrate as high as 65% of total solids. Using the food waste, the feasibility of ethanol production was investigated in a lab-scale fermentor. Pretreatment with hydrolyzing enzymes including carbohydrase, glucoamylase, cellulase and protease were tested for hydrolysis of food waste. The carbohydrase was able to hydrolyze and produce glucose with a glucose yield of 0.63 g glucose/g total solid. Enzymatic hydrolysis and ethanol fermentation by using carbohydrase and Saccharomyces cerevisiae were conducted in the batch mode. For separated hydrolysis and fermentation (SHF), ethanol concentration reached at the level corresponding to an ethanol yield of 0.43 g ethanol/g total solids. For simultaneous saccharification and fermentation (SSF), the ethanol yield was 0.31 g ethanol/g total solids. During the continuous operation of SHF, the volumetric ethanol production rate was 1.18 g/lh with an ethanol yield of 0.3g ethanol/g total solids. For SSF process, the volumetric ethanol production rate was 0.8 g/lh with an ethanol yield of 0.2g ethanol/g total solids.
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Affiliation(s)
- Jae Hyung Kim
- Graduate School of Energy and Environment, Seoul National University of Science and Technology, 172 Gongneung-2 Dong, Nowon-Gu, Seoul 139-743, South Korea
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Abdel-Rahman MA, Tashiro Y, Sonomoto K. Lactic acid production from lignocellulose-derived sugars using lactic acid bacteria: overview and limits. J Biotechnol 2011; 156:286-301. [PMID: 21729724 DOI: 10.1016/j.jbiotec.2011.06.017] [Citation(s) in RCA: 264] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 05/31/2011] [Accepted: 06/17/2011] [Indexed: 10/18/2022]
Abstract
Lactic acid is an industrially important product with a large and rapidly expanding market due to its attractive and valuable multi-function properties. The economics of lactic acid production by fermentation is dependent on many factors, of which the cost of the raw materials is very significant. It is very expensive when sugars, e.g., glucose, sucrose, starch, etc., are used as the feedstock for lactic acid production. Therefore, lignocellulosic biomass is a promising feedstock for lactic acid production considering its great availability, sustainability, and low cost compared to refined sugars. Despite these advantages, the commercial use of lignocellulose for lactic acid production is still problematic. This review describes the "conventional" processes for producing lactic acid from lignocellulosic materials with lactic acid bacteria. These processes include: pretreatment of the biomass, enzyme hydrolysis to obtain fermentable sugars, fermentation technologies, and separation and purification of lactic acid. In addition, the difficulties associated with using this biomass for lactic acid production are especially introduced and several key properties that should be targeted for low-cost and advanced fermentation processes are pointed out. We also discuss the metabolism of lignocellulose-derived sugars by lactic acid bacteria.
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Affiliation(s)
- Mohamed Ali Abdel-Rahman
- Laboratory of Microbial Technology, Division of Applied Molecular Microbiology and Biomass Chemistry, Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, Hakozaki, Higashi-ku, Fukuoka, Japan
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Wang GS, Pan XJ, Zhu JY, Gleisner R, Rockwood D. Sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust enzymatic saccharification of hardwoods. Biotechnol Prog 2009; 25:1086-93. [PMID: 19551888 DOI: 10.1002/btpr.206] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study demonstrates sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust bioconversion of hardwoods. With only about 4% sodium bisulfite charge on aspen and 30-min pretreatment at temperature 180 degrees C, SPORL can achieve near-complete cellulose conversion to glucose in a wide range of pretreatment liquor of pH 2.0-4.5 in only about 10 h enzymatic hydrolysis. The enzyme loading was about 20 FPU cellulase plus 30 CBU beta-glucosidase per gram of cellulose. The production of fermentation inhibitor furfural was less than 20 mg/g of aspen wood at pH 4.5. With pH 4.5, SPORL avoided reactor corrosion problem and eliminated the need for substrate neutralization prior to enzymatic hydrolysis. Similar results were obtained from maple and eucalyptus.
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Affiliation(s)
- G S Wang
- Tianjin Key Laboratory of Pulp and Paper, Tianjin University Science and Technology, Tianjin, China
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Zhu JY, Pan XJ, Wang GS, Gleisner R. Sulfite pretreatment (SPORL) for robust enzymatic saccharification of spruce and red pine. BIORESOURCE TECHNOLOGY 2009; 100:2411-8. [PMID: 19119005 DOI: 10.1016/j.biortech.2008.10.057] [Citation(s) in RCA: 198] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Revised: 10/21/2008] [Accepted: 10/23/2008] [Indexed: 05/05/2023]
Abstract
This study established a novel process using sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust and efficient bioconversion of softwoods. The process consists of sulfite treatment of wood chips under acidic conditions followed by mechanical size reduction using disk refining. The results indicated that after the SPORL pretreatment of spruce chips with 8-10% bisulfite and 1.8-3.7% sulfuric acid on oven dry (od) wood at 180 degrees C for 30 min, more than 90% cellulose conversion of substrate was achieved with enzyme loading of about 14.6 FPU cellulase plus 22.5 CBU beta-glucosidase per gram of od substrate after 48 h hydrolysis. Glucose yield from enzymatic hydrolysis of the substrate per 100 g of untreated od spruce wood (glucan content 43%) was about 37 g (excluding the dissolved glucose during pretreatment). Hemicellulose removal was found to be as critical as lignin sulfonation for cellulose conversion in the SPORL process. Pretreatment altered the wood chips, which reduced electric energy consumption for size reduction to about 19 Wh/kg od untreated wood, or about 19 g glucose/Wh electricity. Furthermore, the SPORL produced low amounts of fermentation inhibitors, hydroxymethyl furfural (HMF) and furfural, of about 5 and 1 mg/g of untreated od wood, respectively. In addition, similar results were achieved when the SPORL was applied to red pine. By building on the mature sulfite pulping and disk refining technologies already practiced in the pulp and paper industry, the SPORL has very few technological barriers and risks for commercialization.
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Affiliation(s)
- J Y Zhu
- USDA Forest Service, Forest Products Laboratory, Madison, WI 53726, USA.
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Rezaei F, Richard TL, Logan BE. Enzymatic hydrolysis of cellulose coupled with electricity generation in a microbial fuel cell. Biotechnol Bioeng 2008; 101:1163-9. [DOI: 10.1002/bit.22015] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Marques S, Alves L, Roseiro J, Gírio F. Conversion of recycled paper sludge to ethanol by SHF and SSF using Pichia stipitis. BIOMASS AND BIOENERGY 2008; 32:400-406. [PMID: 0 DOI: 10.1016/j.biombioe.2007.10.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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Chen HZ, Xu J, Li ZH. Temperature cycling to improve the ethanol production with solid state simultaneous saccharification and fermentation. APPL BIOCHEM MICRO+ 2007. [DOI: 10.1134/s0003683807010103] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Effect of ethanol and yeast on cellulase activity and hydrolysis of crystalline cellulose. Enzyme Microb Technol 2006. [DOI: 10.1016/j.enzmictec.2006.03.027] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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DEMİRBAŞ AYHAN. Bioethanol from Cellulosic Materials: A Renewable Motor Fuel from Biomass. ACTA ACUST UNITED AC 2005. [DOI: 10.1080/00908310390266643] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Nakasaki K, Adachi T. Effects of intermittent addition of cellulase for production of L-lactic acid from wastewater sludge by simultaneous saccharification and fermentation. Biotechnol Bioeng 2003; 82:263-70. [PMID: 12599252 DOI: 10.1002/bit.10573] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
An attempt was made to create L-lactic acid, a precursor of poly-lactic acid, which is a biodegradable plastic, from wastewater sludge from the paper-manufacturing industry. The sludge contained a high percentage of cellulose and needed to be hydrolyzed to glucose by the action of the cellulase before being treating with lactic acid bacteria. Therefore, a method involving simultaneous saccharification and fermentation (SSF) was carried out. The optimum pH of the SSF for production of the lactic acid by the newly isolated lactic acid bacterium with a high selectively of L-lactic acid was found out to be around pH = 5.0, and the optimum temperature to be approximately 40 degrees C. On the basis of the measurement of the cell density changes in the lactic acid bacteria, it was ascertained that the bacterial activity could continue at a high level for a relatively long period of time, and that the L-lactic acid productivity was diminished by the rapid deactivation of the cellulase. With the intermittent addition of cellulase once daily for the sake of compensating for the cellulase deactivation, the L-lactic acid attained a maximum concentration of 16.9 g/L, i.e., a 72.2% yield based on the potential glucose contained in the sludge under optimum pH and temperature conditions.
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Affiliation(s)
- Kiyohiko Nakasaki
- Department of Materials Science and Chemical Engineering, Shizuoka University, 3-5-1 Johoku, Hamamatsu 432-8561, Japan
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Golias H, Dumsday GJ, Stanley GA, Pamment NB. Evaluation of a recombinant Klebsiella oxytoca strain for ethanol production from cellulose by simultaneous saccharification and fermentation: comparison with native cellobiose-utilising yeast strains and performance in co-culture with thermotolerant yeast and Zymomonas mobilis. J Biotechnol 2002; 96:155-68. [PMID: 12039532 DOI: 10.1016/s0168-1656(02)00026-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
In the simultaneous saccharification and fermentation to ethanol of 100 g l(-1) microcrystalline cellulose, the cellobiose-fermenting recombinant Klebsiella oxytoca P2 outperformed a range of cellobiose-fermenting yeasts used in earlier work, despite producing less ethanol than reported earlier for this organism under similar conditions. The time taken by K. oxytoca P2 to produce up to about 33 g l(-1) ethanol was much less than for any other organism investigated, including ethanol-tolerant strains of Saccharomyces pastorianus, Kluyveromyces marxianus and Zymomonas mobilis. Ultimately, it produced slightly less ethanol (maximum 36 g l(-1)) than these organisms, reflecting its lower ethanol tolerance. Significant advantages were obtained by co-culturing K. oxytoca P2 with S. pastorianus, K. marxianus or Z. mobilis, either isothermally, or in conjunction with temperature-profiling to raise the cellulase activity. Co-cultures produced significantly more ethanol, more rapidly, than either of the constituent strains in pure culture at the same inoculum density. K. oxytoca P2 dominated the early stages of the co-cultures, with ethanol production in the later stages due principally to the more ethanol tolerant strain. The usefulness of K. oxytoca P2 in cellulose simultaneous saccharification and fermentation should be improved by mutation of the strain to increase its ethanol tolerance.
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Affiliation(s)
- Helen Golias
- Department of Chemical Engineering, University of Melbourne, Parkville, Victoria, Australia
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Sun Y, Cheng J. Hydrolysis of lignocellulosic materials for ethanol production: a review. BIORESOURCE TECHNOLOGY 2002; 83:1-11. [PMID: 12058826 DOI: 10.1016/s0960-8524(01)00212-7] [Citation(s) in RCA: 2072] [Impact Index Per Article: 94.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Lignocellulosic biomass can be utilized to produce ethanol, a promising alternative energy source for the limited crude oil. There are mainly two processes involved in the conversion: hydrolysis of cellulose in the lignocellulosic biomass to produce reducing sugars, and fermentation of the sugars to ethanol. The cost of ethanol production from lignocellulosic materials is relatively high based on current technologies, and the main challenges are the low yield and high cost of the hydrolysis process. Considerable research efforts have been made to improve the hydrolysis of lignocellulosic materials. Pretreatment of lignocellulosic materials to remove lignin and hemicellulose can significantly enhance the hydrolysis of cellulose. Optimization of the cellulase enzymes and the enzyme loading can also improve the hydrolysis. Simultaneous saccharification and fermentation effectively removes glucose, which is an inhibitor to cellulase activity, thus increasing the yield and rate of cellulose hydrolysis.
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Affiliation(s)
- Ye Sun
- Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh 27695-7625, USA
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de Palma-Fernandez ER, Gomes E, da Silva R. Purification and characterization of two beta-glucosidases from the thermophilic fungus Thermoascus aurantiacus. Folia Microbiol (Praha) 2002; 47:685-90. [PMID: 12630320 DOI: 10.1007/bf02818672] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
beta-Glucosidase from the fungus Thermoascus aurantiacus grown on semi-solid fermentation medium (using ground corncob as substrate) was partially purified in 5 steps--ultrafiltration, ethanol precipitation, gel filtration and 2 anion exchange chromatography runs, and characterized. After the first anion exchange chromatography, beta-glucosidase activity was eluted in 3 peaks (Gl-1, Gl-2, Gl-3). Only the Gl-2 and Gl-3 fractions were adsorbed on the gel matrix. Gl-2 and Gl-3 exhibited optimum pH at 4.5 and 4.0, respectively. The temperature optimum of both glucosidases was at 75-80 degrees C. The pH stability of Gl-2 (4.0-9.0) was higher than Gl-3 (5.5-8.5); both enzyme activities showed similar patterns of thermostability. Under conditions of denaturing gel chromatography the molar mass of Gl-2 and Gl-3 was 175 and 157 kDa, respectively. Using 4-nitrophenyl beta-D-glucopyranoside as substrate, Km values of 1.17 +/- 0.35 and 1.38 +/- 0.86 mmol/L were determined for Gl-2 and Gl-3, respectively. Both enzymes were inhibited by Ag+ and stimulated by Ca2+.
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Mostafa YS, László E, El-hawary FI. Preliminary communications CELLULASE PRODUCTION AND CONVERSION OF RICE STRAW TO LACTIC ACID BY SIMULTANEOUS SACCHARIFICATION AND FERMENTATION. ACTA ALIMENTARIA 2001. [DOI: 10.1556/aalim.30.2001.3.5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Kheshgi HS, Prince RC, Marland G. THEPOTENTIAL OFBIOMASSFUELS INTHECONTEXT OFGLOBALCLIMATECHANGE: Focus on Transportation Fuels. ACTA ACUST UNITED AC 2000. [DOI: 10.1146/annurev.energy.25.1.199] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Haroon S. Kheshgi
- ExxonMobil Research and Engineering Company, Annandale, New Jersey 08801; e-mail:
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6335; e-mail:
| | - Roger C. Prince
- ExxonMobil Research and Engineering Company, Annandale, New Jersey 08801; e-mail:
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6335; e-mail:
| | - Gregg Marland
- ExxonMobil Research and Engineering Company, Annandale, New Jersey 08801; e-mail:
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6335; e-mail:
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Montesinos T, Navarro J. Production of alcohol from raw wheat flour by Amyloglucosidase and Saccharomyces cerevisiae. Enzyme Microb Technol 2000; 27:362-370. [PMID: 10938415 DOI: 10.1016/s0141-0229(00)00211-8] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Ethanol production, by a simultaneous saccharification and fermentation process from raw wheat flour, has been performed by Saccharomyces cerevisiae and a low level of amyloglucosidase enzyme. The fermentation time was about 60 h after a 6 h pre-saccharification, with an amyloglucosidase (AMG) level of 270 AGU. kg(-1) starch, but only 31 h with a simultaneous saccharification fermentation process (SSF). When an AMG level of 540 AGU. kg(-1) starch was used, the time decreased to 21 h, giving an ethanol concentration of 67 g. l(-1). Sugar composition of the wort after the liquefaction may be responsible of the difference between these two process. Maltose, a fermentable sugar, was produced in high concentration during the liquefaction, allowing a shorter process period, counteracting the effect of the slow starch hydrolysis at 35 degrees C (SSF temperature).
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Affiliation(s)
- T Montesinos
- Université Montpellier II. ISIM., Laboratoire de Génie Biologique et Science des Aliments, équipe de Biochimie et Microbiologie Industrielles, place E. Bataillon, 34095 5, Montpellier cedex, France
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27
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Bollók M, Réczey K. Cellulase enzyme production by various fungal strains on different carbon sources. ACTA ALIMENTARIA 2000. [DOI: 10.1556/aalim.29.2000.2.6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Gong CS, Cao NJ, Du J, Tsao GT. Ethanol production from renewable resources. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 1999; 65:207-41. [PMID: 10533436 DOI: 10.1007/3-540-49194-5_9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Vast amounts of renewable biomass are available for conversion to liquid fuel, ethanol. In order to convert biomass to ethanol, the efficient utilization of both cellulose-derived and hemicellulose-derived carbohydrates is essential. Six-carbon sugars are readily utilized for this purpose. Pentoses, on the other hand, are more difficult to convert. Several metabolic factors limit the efficient utilization of pentoses (xylose and arabinose). Recent developments in the improvement of microbial cultures provide the versatility of conversion of both hexoses and pentoses to ethanol more efficiently. In addition, novel bioprocess technologies offer a promising prospective for the efficient conversion of biomass and recovery of ethanol.
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Affiliation(s)
- C S Gong
- Laboratory of Renewable Resources Engineering, Purdue University, West Lafayette, IN 47907, USA
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Chandrakant P, Bisaria VS. Simultaneous bioconversion of cellulose and hemicellulose to ethanol. Crit Rev Biotechnol 1999; 18:295-331. [PMID: 9887507 DOI: 10.1080/0738-859891224185] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Lignocellulosic materials containing cellulose, hemicellulose, and lignin as their main constituents are the most abundant renewable organic resource present on Earth. The conversion of both cellulose and hemicellulose for production of fuel ethanol is being studied intensively with a view to develop a technically and economically viable bioprocess. The fermentation of glucose, the main constituent of cellulose hydrolyzate, to ethanol can be carried out efficiently. On the other hand, although bioconversion of xylose, the main pentose sugar obtained on hydrolysis of hemicellulose, to ethanol presents a biochemical challenge, especially if it is present along with glucose, it needs to be fermented to make the biomass-to-ethanol process economical. A lot of attention therefore has been focussed on the utilization of both glucose and xylose to ethanol. Accordingly, while describing the advancements that have taken place to get xylose converted efficiently to ethanol by xylose-fermenting organisms, the review deals mainly with the strategies that have been put forward for bioconversion of both the sugars to achieve high ethanol concentration, yield, and productivity. The approaches, which include the use of (1) xylose-fermenting yeasts alone, (2) xylose isomerase enzyme as well as yeast, (3) immobilized enzymes and cells, and (4) sequential fermentation and co-culture process are described with respect to their underlying concepts and major limitations. Genetic improvements in the cultures have been made either to enlarge the range of substrate utilization or to channel metabolic intermediates specifically toward ethanol. These contributions represent real significant advancements in the field and have also been adequately dealt with from the point of view of their impact on utilization of both cellulose and hemicellulose sugars to ethanol.
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Affiliation(s)
- P Chandrakant
- Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, Hauz Khas, New Delhi, India
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Wu Z, Lee YY. Nonisothermal simultaneous saccharification and fermentation for direct conversion of lignocellulosic biomass to ethanol. Appl Biochem Biotechnol 1998; 70-72:479-92. [DOI: 10.1007/bf02920161] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Production of 2,3- butanediol from pretreated corn cob byKlebsiella oxytoca in the presence of fungal cellulase. Appl Biochem Biotechnol 1997; 63-65:129-39. [DOI: 10.1007/bf02920419] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Cao NJ, Krishnan MS, Du JX, Gong CS, Ho NWY, Chen ZD, Tsao GT. Ethanol production from corn cob pretreated by the ammonia steeping process using genetically engineered yeast. Biotechnol Lett 1996. [DOI: 10.1007/bf00129723] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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