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Sánchez-Muñoz S, Balbino TR, de Oliveira F, Rocha TM, Barbosa FG, Vélez-Mercado MI, Marcelino PRF, Antunes FAF, Moraes EJC, dos Santos JC, da Silva SS. Surfactants, Biosurfactants, and Non-Catalytic Proteins as Key Molecules to Enhance Enzymatic Hydrolysis of Lignocellulosic Biomass. Molecules 2022; 27:8180. [PMID: 36500273 PMCID: PMC9739445 DOI: 10.3390/molecules27238180] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/17/2022] [Accepted: 11/21/2022] [Indexed: 11/27/2022] Open
Abstract
Lignocellulosic biomass (LCB) has remained a latent alternative resource to be the main substitute for oil and its derivatives in a biorefinery concept. However, its complex structure and the underdeveloped technologies for its large-scale processing keep it in a state of constant study trying to establish a consolidated process. In intensive processes, enzymes have been shown to be important molecules for the fractionation and conversion of LCB into biofuels and high-value-added molecules. However, operational challenges must be overcome before enzyme technology can be the main resource for obtaining second-generation sugars. The use of additives is shown to be a suitable strategy to improve the saccharification process. This review describes the mechanisms, roles, and effects of using additives, such as surfactants, biosurfactants, and non-catalytic proteins, separately and integrated into the enzymatic hydrolysis process of lignocellulosic biomass. In doing so, it provides a technical background in which operational biomass processing hurdles such as solids and enzymatic loadings, pretreatment burdens, and the unproductive adsorption phenomenon can be addressed.
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Affiliation(s)
- Salvador Sánchez-Muñoz
- Bioprocesses and Sustainable Products Laboratory, Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), Lorena 12.602.810., Brazil
| | - Thércia R. Balbino
- Bioprocesses and Sustainable Products Laboratory, Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), Lorena 12.602.810., Brazil
| | - Fernanda de Oliveira
- Bioprocesses and Sustainable Products Laboratory, Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), Lorena 12.602.810., Brazil
| | - Thiago M. Rocha
- Bioprocesses and Sustainable Products Laboratory, Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), Lorena 12.602.810., Brazil
| | - Fernanda G. Barbosa
- Bioprocesses and Sustainable Products Laboratory, Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), Lorena 12.602.810., Brazil
| | - Martha I. Vélez-Mercado
- Bioprocesses and Sustainable Products Laboratory, Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), Lorena 12.602.810., Brazil
| | - Paulo R. F. Marcelino
- Bioprocesses and Sustainable Products Laboratory, Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), Lorena 12.602.810., Brazil
| | - Felipe A. F. Antunes
- Bioprocesses and Sustainable Products Laboratory, Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), Lorena 12.602.810., Brazil
| | - Elisangela J. C. Moraes
- Bioprocesses and Sustainable Products Laboratory, Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), Lorena 12.602.810., Brazil
| | - Julio C. dos Santos
- Biopolymers, Bioreactors, and Process Simulation Laboratory, Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), Lorena 12.602.810., Brazil
| | - Silvio S. da Silva
- Bioprocesses and Sustainable Products Laboratory, Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), Lorena 12.602.810., Brazil
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Sánchez Muñoz S, Rocha Balbino T, Mier Alba E, Gonçalves Barbosa F, Tonet de Pier F, Lazuroz Moura de Almeida A, Helena Balan Zilla A, Antonio Fernandes Antunes F, Terán Hilares R, Balagurusamy N, César Dos Santos J, Silvério da Silva S. Surfactants in biorefineries: Role, challenges & perspectives. BIORESOURCE TECHNOLOGY 2022; 345:126477. [PMID: 34864172 DOI: 10.1016/j.biortech.2021.126477] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/26/2021] [Accepted: 11/28/2021] [Indexed: 06/13/2023]
Abstract
The use of lignocellulosic biomass (LCB) as feedstock has received increasing attention as an alternative to fossil-based refineries. Initial steps such as pretreatment and enzymatic hydrolysis are essential to breakdown the complex structure of LCB to make the sugar molecules available to obtain bioproducts by fermentation. However, these steps increase the cost of the bioproduct and often reduces its competitiveness against synthetic products. Currently, the use of surfactants has shown considerable potential to enhance lignocellulosic biomass processing. This review addresses the main mechanisms and role of surfactants as key molecules in various steps of biorefinery processes, viz., increasing the removal of lignin and hemicellulose during the pretreatments, increasing enzymatic stability and enhancing the accessibility of enzymes to the polymeric fractions, and improving the downstream process during fermentation. Further, technical advances, challenges in application of surfactants, and future perspectives to augment the production of several high value-added bioproducts have been discussed.
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Affiliation(s)
- Salvador Sánchez Muñoz
- Bioprocesses and sustainable products laboratory. Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), 12.602.810. Lorena, SP, Brazil
| | - Thércia Rocha Balbino
- Bioprocesses and sustainable products laboratory. Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), 12.602.810. Lorena, SP, Brazil
| | - Edith Mier Alba
- Bioprocesses and sustainable products laboratory. Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), 12.602.810. Lorena, SP, Brazil
| | - Fernanda Gonçalves Barbosa
- Bioprocesses and sustainable products laboratory. Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), 12.602.810. Lorena, SP, Brazil
| | - Fernando Tonet de Pier
- Bioprocesses and sustainable products laboratory. Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), 12.602.810. Lorena, SP, Brazil
| | - Alexandra Lazuroz Moura de Almeida
- Bioprocesses and sustainable products laboratory. Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), 12.602.810. Lorena, SP, Brazil
| | - Ana Helena Balan Zilla
- Bioprocesses and sustainable products laboratory. Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), 12.602.810. Lorena, SP, Brazil
| | - Felipe Antonio Fernandes Antunes
- Bioprocesses and sustainable products laboratory. Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), 12.602.810. Lorena, SP, Brazil
| | - Ruly Terán Hilares
- Laboratório de Materiales, Universidad Católica de Santa María - UCSM. Urb. San José, San José s/n, Yanahuara, Arequipa, Perú
| | - Nagamani Balagurusamy
- Bioremediation laboratory. Faculty of Biological Sciences, Autonomous University of Coahuila (UA de C), Torreón Campus, 27000 Coah, México
| | - Júlio César Dos Santos
- Biopolymers, bioreactors, and process simulation laboratory. Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), 12.602.810. Lorena, SP, Brazil
| | - Silvio Silvério da Silva
- Bioprocesses and sustainable products laboratory. Department of Biotechnology, Engineering School of Lorena, University of São Paulo (EEL-USP), 12.602.810. Lorena, SP, Brazil.
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Strategies towards Reduction of Cellulases Consumption: Debottlenecking the Economics of Lignocellulosics Valorization Processes. POLYSACCHARIDES 2021. [DOI: 10.3390/polysaccharides2020020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Lignocellulosic residues have been receiving growing interest as a promising source of polysaccharides, which can be converted into a variety of compounds, ranging from biofuels to bioplastics. Most of these can replace equivalent products traditionally originated from petroleum, hence representing an important environmental advantage. Lignocellulosic materials are theoretically unlimited, cheaper and may not compete with food crops. However, the conversion of these materials to simpler sugars usually requires cellulolytic enzymes. Being still associated with a high cost of production, cellulases are commonly considered as one of the main obstacles in the economic valorization of lignocellulosics. This work provides a brief overview of some of the most studied strategies that can allow an important reduction of cellulases consumption, hence improving the economy of lignocellulosics conversion. Cellulases recycling is initially discussed regarding the main processes to recover active enzymes and the most important factors that may affect enzyme recyclability. Similarly, the potential of enzyme immobilization is analyzed with a special focus on the contributions that some elements of the process can offer for prolonged times of operation and improved enzyme stability and robustness. Finally, the emergent concept of consolidated bioprocessing (CBP) is also described in the particular context of a potential reduction of cellulases consumption.
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Glucan Conversion and Membrane Recovery of Biomimetic Cellulosomes During Lignocellulosic Biomass Hydrolysis. Appl Biochem Biotechnol 2021; 193:2830-2842. [PMID: 33871766 DOI: 10.1007/s12010-021-03569-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 04/08/2021] [Indexed: 10/21/2022]
Abstract
Enzyme immobilization has been identified as one way to recycle enzymes and reduce processing costs during enzymatic hydrolysis of lignocellulosic materials. However, most immobilization methods have not been attractive to lignocellulosic processing plants. In this study, cellulase enzymes were attached to a copolymer of glycidyl methacrylate (GMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) to make polymer-enzyme conjugates (PECs) and facilitate recovery using a 50-kDa molecular weight cutoff membrane. Glucan conversion during biomass hydrolysis was investigated using new PECs and PECs recovered after an initial hydrolysis stage. Enzyme immobilization on PECs did not reduce effectiveness during the initial hydrolysis. Temperature and pH showed similar effects on free enzymes and PECs. PECs facilitated higher conversion rates than free enzymes at high biomass loadings. Recovered PECs were used to achieve approximately 100% glucan conversion in a subsequent hydrolysis step when supplemented with 40% of the free enzyme used in the first stage. The combination of PECs and membrane recovery has the potential to reduce hydrolysis cost during cellulosic bioprocessing.
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Affiliation(s)
- Susanne Striegler
- Department of Chemistry and Biochemistry, University of Arkansas, 345 North Campus Drive, Fayetteville, Arkansas 72701, United States
| | - Babloo Sharma
- Department of Chemistry and Biochemistry, University of Arkansas, 345 North Campus Drive, Fayetteville, Arkansas 72701, United States
| | - Ifedi Orizu
- Department of Chemistry and Biochemistry, University of Arkansas, 345 North Campus Drive, Fayetteville, Arkansas 72701, United States
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Effects of Biosurfactants on Enzymatic Saccharification and Fermentation of Pretreated Softwood. Molecules 2020; 25:molecules25163559. [PMID: 32764287 PMCID: PMC7465028 DOI: 10.3390/molecules25163559] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/31/2020] [Accepted: 08/02/2020] [Indexed: 12/21/2022] Open
Abstract
The enzymatic hydrolysis of cellulose is inhibited by non-productive adsorption of cellulases to lignin, and that is particularly problematic with lignin-rich materials such as softwood. Although conventional surfactants alleviate non-productive adsorption, using biosurfactants in softwood hydrolysis has not been reported. In this study, the effects of four biosurfactants, namely horse-chestnut escin, Pseudomonas aeruginosa rhamnolipid, and saponins from red and white quinoa varieties, on the enzymatic saccharification of steam-pretreated spruce were investigated. The used biosurfactants improved hydrolysis, and the best-performing one was escin, which led to cellulose conversions above 90%, decreased by around two-thirds lignin inhibition of Avicel hydrolysis, and improved hydrolysis of pretreated spruce by 24%. Red quinoa saponins (RQS) addition resulted in cellulose conversions above 80%, which was around 16% higher than without biosurfactants, and it was more effective than adding rhamnolipid or white quinoa saponins. Cellulose conversion improved with the increase in RQS addition up to 6 g/100 g biomass, but no significant changes were observed above that dosage. Although saponins are known to inhibit yeast growth, no inhibition of Saccharomyces cerevisiae fermentation of hydrolysates produced with RQS addition was detected. This study shows the potential of biosurfactants for enhancing the enzymatic hydrolysis of steam-pretreated softwood.
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Pallapolu VR, Shi S, Kang L, Kothari U, Li J. Boost Effect of Water-Soluble Polymers on Enzymatic Hydrolysis of Lignocellulosic Biomass. Ind Eng Chem Res 2020. [DOI: 10.1021/acs.iecr.9b05850] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Venkata R. Pallapolu
- Chemical Engineering Department, Auburn University, Auburn, Alabama 36849, United States
| | - Suan Shi
- Department of Biosystems Engineering, Auburn University, Auburn, Alabama 36849, United States
| | - Li Kang
- Chemical Engineering Department, Auburn University, Auburn, Alabama 36849, United States
| | - Urvi Kothari
- Chemical Engineering Department, Auburn University, Auburn, Alabama 36849, United States
| | - Jing Li
- Chemical Engineering Department, Auburn University, Auburn, Alabama 36849, United States
- The Alabama Center for Paper and Bioresource Engineering, Auburn University, Auburn, Alabama 36849, United States
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Wang X, Zeng J, Gao W, Chen K, Wang B, Xu J. Endoglucanase recycling for disintegrating cellulosic fibers to fibrils. Carbohydr Polym 2019; 223:115052. [DOI: 10.1016/j.carbpol.2019.115052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 07/02/2019] [Indexed: 10/26/2022]
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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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Li H, Wang C, Xiao W, Yang Y, Hu P, Dai Y, Jiang Z. Dissecting the effect of polyethylene glycol on the enzymatic hydrolysis of diverse lignocellulose. Int J Biol Macromol 2019; 131:676-681. [PMID: 30904528 DOI: 10.1016/j.ijbiomac.2019.03.131] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/06/2019] [Accepted: 03/19/2019] [Indexed: 12/20/2022]
Abstract
Natural lignocellulose is used as raw material to produce chemicals through biological transformation. The accessibility of cellulase to substrate was also one of the limiting factors of industrial production. Polyethylene glycol (PEG) can be used as additive in enzymatic hydrolysis of lignocellulose. In this study, enzymatic activity on simultaneous or non-simultaneous addition of PEG 4000 was investigated, and the partly delignified rice straw, the rice straw and filter paper were used as substrates, respectively. Enzyme activity was characterized by reducing sugar concentration in supernatant which was quantified through 3,5-dinitrosalicylic acid (DNS) method. Addition of PEG has been proven to facilitate enzymatic hydrolysis of lignocellulosic materials. Furthermore, PEG had the positive effect on hydrolytic enzyme activity of pure cellulose materials without lignin. Changes in lignocellulose materials have been observed by inverted microscope and Scanning electron microscope (SEM), and no chemical changes were shown by Fourier transform infrared spectroscopy (FTIR). The promotion of PEG on enzymatic hydrolysis of pure cellulose materials may be due to its loose physical structure and similar phenomenon in natural lignin materials. PEG loosens the physical structure of lignocellulose, thus facilitating enzymatic hydrolysis. This may be a new idea to optimize the lignocellulosic enzymatic hydrolysis process.
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Affiliation(s)
- Huanan Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China
| | - Chaoying Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China
| | - Wenjing Xiao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Yuxian Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Pan Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, PR China
| | - Yujun Dai
- Hubei Province Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients, Hubei Engineering University, Xiaogan 432000, PR China
| | - Zhengbing Jiang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan 430062, PR China; Hubei Key Laboratory of Industrial Biotechnology, School of Life Science, Hubei University, Wuhan 430062, PR China.
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11
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Buyel JF. Plant Molecular Farming - Integration and Exploitation of Side Streams to Achieve Sustainable Biomanufacturing. FRONTIERS IN PLANT SCIENCE 2019; 9:1893. [PMID: 30713542 PMCID: PMC6345721 DOI: 10.3389/fpls.2018.01893] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 12/06/2018] [Indexed: 05/22/2023]
Abstract
Plants have unique advantages over other systems such as mammalian cells for the production of valuable small molecules and proteins. The benefits cited most often include safety due to the absence of replicating human pathogens, simplicity because sterility is not required during production, scalability due to the potential for open-field cultivation with transgenic plants, and the speed of transient expression potentially providing gram quantities of product in less than 4 weeks. Initially there were also significant drawbacks, such as the need to clarify feed streams with a high particle burden and the large quantities of host cell proteins, but efficient clarification is now readily achieved. Several additional advantages have also emerged reflecting the fact that plants are essentially biodegradable, single-use bioreactors. This article will focus on the exploitation of this concept for the production of biopharmaceutical proteins, thus improving overall process economics. Specifically, we will discuss the single-use properties of plants, the sustainability of the production platform, and the commercial potential of different biomass side streams. We find that incorporating these side streams through rational process integration has the potential to more than double the revenue that can currently be achieved using plant-based production systems.
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Affiliation(s)
- Johannes F. Buyel
- Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany
- Institute for Molecular Biotechnology, RWTH Aachen University, Aachen, Germany
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Zhang H, Lyu G, Zhang A, Li X, Xie J. Effects of ferric chloride pretreatment and surfactants on the sugar production from sugarcane bagasse. BIORESOURCE TECHNOLOGY 2018; 265:93-101. [PMID: 29885498 DOI: 10.1016/j.biortech.2018.05.111] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 05/08/2023]
Abstract
An efficient pretreatment with various concentrations of FeCl3 (0.005-0.2 mol/L) was developed to extract hemicellulose in sugarcane bagasse and enhance the enzymatic hydrolysis of cellulose in pretreated solids. It was found that 0.025 mol/L FeCl3 pretreated substrate yielded a high glucose yield of 80.1% during enzymatic hydrolysis. Then the characterization of raw material and pretreated solids was carried out to better understand how hemicellulose removal affected subsequent enzymatic hydrolysis. In addition, Tween 80 and Bovine Serum Albumin (BSA) were added to promote enzymatic hydrolysis of pretreated substrate. Together with that obtained from pretreatment, the highest glucose yield reached 97.7% with addition of Tween 80, meanwhile, a reduction of 50% loading of enzyme yielded the same level of glucose. However, the increased yields with additives decreased gradually as the hydrolysis time was extended. Furthermore, the enhancement mechanisms of Tween 80 and BSA were determined.
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Affiliation(s)
- Hongdan Zhang
- College of Forestry and Landscape Architecture, Key Laboratory of Energy Plants Resource and Utilization, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, PR China; Key Laboratory of Pulp and Paper Science & Technology of Ministry of Education of China, Qilu University of Technology, Jinan 250353, PR China; State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, PR China.
| | - Gaojin Lyu
- Key Laboratory of Pulp and Paper Science & Technology of Ministry of Education of China, Qilu University of Technology, Jinan 250353, PR China
| | - Aiping Zhang
- College of Forestry and Landscape Architecture, Key Laboratory of Energy Plants Resource and Utilization, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, PR China
| | - Xin Li
- College of Forestry and Landscape Architecture, Key Laboratory of Energy Plants Resource and Utilization, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, PR China
| | - Jun Xie
- College of Forestry and Landscape Architecture, Key Laboratory of Energy Plants Resource and Utilization, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, PR China.
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Cizeikiene D, Juodeikiene G, Damasius J. Use of wheat straw biomass in production of L-lactic acid applying biocatalysis and combined lactic acid bacteria strains belonging to the genus Lactobacillus. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2018. [DOI: 10.1016/j.bcab.2018.06.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Gomes D, Gama M, Domingues L. Determinants on an efficient cellulase recycling process for the production of bioethanol from recycled paper sludge under high solid loadings. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:111. [PMID: 29686729 PMCID: PMC5901881 DOI: 10.1186/s13068-018-1103-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 03/31/2018] [Indexed: 06/08/2023]
Abstract
BACKGROUND In spite of the continuous efforts and investments in the last decades, lignocellulosic ethanol is still not economically competitive with fossil fuels. Optimization is still required in different parts of the process. Namely, the cost effective usage of enzymes has been pursued by different strategies, one of them being recycling. RESULTS Cellulase recycling was analyzed on recycled paper sludge (RPS) conversion into bioethanol under intensified conditions. Different cocktails were studied regarding thermostability, hydrolysis efficiency, distribution in the multiphasic system and recovery from solid. Celluclast showed inferior stability at higher temperatures (45-55 °C), nevertheless its performance at moderate temperatures (40 °C) was slightly superior to other cocktails (ACCELLERASE®1500 and Cellic®CTec2). Celluclast distribution in the solid-liquid medium was also more favorable, enabling to recover 88% of final activity at the end of the process. A central composite design studied the influence of solid concentration and enzyme dosage on RPS conversion by Celluclast. Solids concentration showed a significant positive effect on glucose production, no major limitations being found from utilizing high amounts of solids under the studied conditions. Increasing enzyme loading from 20 to 30 FPU/gcellulose had no significant effect on sugars production, suggesting that 22% solids and 20 FPU/gcellulose are the best operational conditions towards an intensified process. Applying these, a system of multiple rounds of hydrolysis with enzyme recycling was implemented, allowing to maintain the steady levels of enzyme activity with only 50% of enzyme on each recycling stage. Additionally, interesting levels of solid conversion (70-81%) were also achieved, leading to considerable improvements on glucose and ethanol production comparatively with the reports available so far (3.4- and 3.8-fold, respectively). CONCLUSIONS Enzyme recycling viability depends on enzyme distribution between the solid and liquid phases at the end of hydrolysis, as well as enzymes thermostability. Both are critical features to be observed for a judicious choice of enzyme cocktail. This work demonstrates that enzyme recycling in intensified biomass degradation can be achieved through simple means. The process is possibly much more effective at larger scale, hence novel enzyme formulations favoring this possibility should be developed for industrial usage.
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Affiliation(s)
- Daniel Gomes
- Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Miguel Gama
- Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Lucília Domingues
- Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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15
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Zhang H, Zhang S, Yuan H, Lyu G, Xie J. FeCl 3-catalyzed ethanol pretreatment of sugarcane bagasse boosts sugar yields with low enzyme loadings and short hydrolysis time. BIORESOURCE TECHNOLOGY 2018; 249:395-401. [PMID: 29059622 DOI: 10.1016/j.biortech.2017.10.053] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Revised: 10/11/2017] [Accepted: 10/12/2017] [Indexed: 05/22/2023]
Abstract
An organosolv pretreatment system consisting of 60% ethanol and 0.025 mol·L-1 FeCl3 under various temperatures was developed in this study. During the pretreatment, the highest xylose yield was 11.4 g/100 g raw material, representing 49.8% of xylose in sugarcane bagasse. Structural features of raw material and pretreated substrates were characterized to better understand how hemicellulose removal and delignification affected subsequent enzymatic hydrolysis. The 160 °C pretreated solid presented a remarkable glucose yield of 93.8% for 72 h. Furthermore, the influence of different additives on the enzymatic hydrolysis of pretreated solid was investigated. The results indicated that the addition of Tween 80 shortened hydrolysis time to 6 h and allowed a 50% reduction of enzyme loading to achieve the same level of glucose yield. This work suggested that FeCl3-catalyzed organosolv pretreatment could improve the enzymatic hydrolysis significantly and reduce the hydrolysis time and enzyme dosage with the addition of Tween 80.
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Affiliation(s)
- Hongdan Zhang
- College of Forestry and Landscape Architecture, Key Laboratory of Energy Plants Resource and Utilization, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, PR China; Guangdong Provincial Key Laboratory of New and Renewable Energy Research, Development, and Application, Guangzhou 510640, PR China; Key Laboratory of Pulp and Paper Science & Technology of Ministry of Education of China, Qilu University of Technology, Jinan 250353, PR China
| | - Shuaishuai Zhang
- College of Forestry and Landscape Architecture, Key Laboratory of Energy Plants Resource and Utilization, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, PR China
| | - Hongyou Yuan
- Guangdong Provincial Key Laboratory of New and Renewable Energy Research, Development, and Application, Guangzhou 510640, PR China
| | - Gaojin Lyu
- Key Laboratory of Pulp and Paper Science & Technology of Ministry of Education of China, Qilu University of Technology, Jinan 250353, PR China
| | - Jun Xie
- College of Forestry and Landscape Architecture, Key Laboratory of Energy Plants Resource and Utilization, Ministry of Agriculture, South China Agricultural University, Guangzhou 510642, PR China.
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Conversion of Lignocellulosic Biomass Into Platform Chemicals for Biobased Polyurethane Application. ADVANCES IN BIOENERGY 2018. [DOI: 10.1016/bs.aibe.2018.03.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Smit AT, Huijgen WJJ. The promotional effect of water-soluble extractives on the enzymatic cellulose hydrolysis of pretreated wheat straw. BIORESOURCE TECHNOLOGY 2017; 243:994-999. [PMID: 28753744 DOI: 10.1016/j.biortech.2017.07.072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 07/12/2017] [Accepted: 07/13/2017] [Indexed: 06/07/2023]
Abstract
Enzymatic cellulose hydrolysis of pretreated wheat straw pulp to glucose is enhanced when the hydrolysis is performed in the presence of an aqueous extract of the wheat straw. A relative digestibility increase of about 10% has been observed for organosolv, alkaline and dilute acid pretreated wheat straw pulp (enzyme dose 2.5FPU/g pulp). At lower enzyme doses, the extract effect increases leading to an enzyme dose reduction of 40% to obtain a glucose yield of 75% within 48h using organosolv wheat straw pulp. Possibly, cellulase deactivation by irreversible binding to pulp lignin is reduced by competition with proteins in the extract. However, since the extract effect has also been demonstrated for lignin-lean substrates, other effects like improved accessibility of the pulp cellulose (amorphogenesis) cannot be excluded. Overall, this contribution demonstrates the positive effect of biomass extractives on enzymatic cellulose digestibility, thereby reducing costs for 2G biofuels and bio-based chemicals.
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Affiliation(s)
- A T Smit
- Energy Research Centre of the Netherlands (ECN), Biomass & Energy Efficiency, P.O. Box 1, 1755 ZG Petten, The Netherlands.
| | - W J J Huijgen
- Energy Research Centre of the Netherlands (ECN), Biomass & Energy Efficiency, P.O. Box 1, 1755 ZG Petten, The Netherlands
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Wang Q, Liu S, Yang G, Chen J, Ji X, Ni Y. Recycling cellulase towards industrial application of enzyme treatment on hardwood kraft-based dissolving pulp. BIORESOURCE TECHNOLOGY 2016; 212:160-163. [PMID: 27099940 DOI: 10.1016/j.biortech.2016.04.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 04/10/2016] [Accepted: 04/11/2016] [Indexed: 06/05/2023]
Abstract
Cost-effectiveness is vital for enzymatic treatment of dissolving pulp towards industrial application. The strategy of cellulase recycling with fresh cellulase addition was demonstrated in this work to activate the dissolving pulp, i.e. decreasing viscosity and increasing Fock reactivity. Results showed that 48.8-35.1% of cellulase activity can be recovered from the filtered liquor in five recycle rounds, which can be reused for enzymatic treatment of dissolving pulp. As a result, the recycling cellulase with addition fresh cellulase of 1mg/g led to the pulp of viscosity 470mL/g and Fock reactivity 80%, which is comparable with cellulase charge of 2mg/g. Other pulp properties such as alpha-cellulose, alkaline solubility and molecular weight distribution were also determined. Additionally, a zero-release of recycling cellulase treatment was proposed to integrate into the dissolving pulp production process.
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Affiliation(s)
- Qiang Wang
- Key Lab of Paper Science and Technology of Ministry of Education, Qilu University of Technology, Jinan, Shandong Province 250353, China; State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, Guangdong Province 510640, China; Limerick Pulp and Paper Centre, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada.
| | - Shanshan Liu
- Key Lab of Paper Science and Technology of Ministry of Education, Qilu University of Technology, Jinan, Shandong Province 250353, China; State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, Guangdong Province 510640, China; Limerick Pulp and Paper Centre, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada
| | - Guihua Yang
- Key Lab of Paper Science and Technology of Ministry of Education, Qilu University of Technology, Jinan, Shandong Province 250353, China
| | - Jiachuan Chen
- Key Lab of Paper Science and Technology of Ministry of Education, Qilu University of Technology, Jinan, Shandong Province 250353, China
| | - Xingxiang Ji
- Key Lab of Paper Science and Technology of Ministry of Education, Qilu University of Technology, Jinan, Shandong Province 250353, China; State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, Guangdong Province 510640, China
| | - Yonghao Ni
- Limerick Pulp and Paper Centre, University of New Brunswick, Fredericton, New Brunswick E3B 5A3, Canada
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Kim SM, Dien BS, Singh V. Promise of combined hydrothermal/chemical and mechanical refining for pretreatment of woody and herbaceous biomass. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:97. [PMID: 27141232 PMCID: PMC4852465 DOI: 10.1186/s13068-016-0505-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/12/2016] [Indexed: 05/07/2023]
Abstract
Production of advanced biofuels from woody and herbaceous feedstocks is moving into commercialization. Biomass needs to be pretreated to overcome the physicochemical properties of biomass that hinder enzyme accessibility, impeding the conversion of the plant cell walls to fermentable sugars. Pretreatment also remains one of the most costly unit operations in the process and among the most critical because it is the source of chemicals that inhibit enzymes and microorganisms and largely determines enzyme loading and sugar yields. Pretreatments are categorized into hydrothermal (aqueous)/chemical, physical, and biological pretreatments, and the mechanistic details of which are briefly outlined in this review. To leverage the synergistic effects of different pretreatment methods, conducting two or more pretreatments consecutively has gained attention. Especially, combining hydrothermal/chemical pretreatment and mechanical refining, a type of physical pretreatment, has the potential to be applied to an industrial plant. Here, the effects of the combined pretreatment (combined hydrothermal/chemical pretreatment and mechanical refining) on energy consumption, physical structure, sugar yields, and enzyme dosage are summarized.
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Affiliation(s)
- Sun Min Kim
- />Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
| | - Bruce S. Dien
- />Bioenergy Research Unit, Agricultural Research Service, USDA, National Center for Agricultural Utilization Research, Peoria, IL 61604 USA
| | - Vijay Singh
- />Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801 USA
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20
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Zhou Y, Chen H, Qi F, Zhao X, Liu D. Non-ionic surfactants do not consistently improve the enzymatic hydrolysis of pure cellulose. BIORESOURCE TECHNOLOGY 2015; 182:136-143. [PMID: 25689307 DOI: 10.1016/j.biortech.2015.01.137] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/27/2015] [Accepted: 01/30/2015] [Indexed: 05/18/2023]
Abstract
Non-ionic surfactants have been frequently reported to improve the enzymatic hydrolysis of pretreated lignocellulosic biomass and pure cellulose. However, how the hydrolysis condition, substrate structure and cellulase formulation affect the beneficial action of surfactants has not been well elucidated. In this work, it was found that the enzymatic hydrolysis of pure cellulose was not consistently improved by surfactants. Contrarily, high surfactant concentration, e.g. 5 g/L, which greatly improved the hydrolysis of dilute acid pretreated substrates, actually showed notable inhibition to pure cellulose conversion in the late phase of hydrolysis. Under an optimal hydrolysis condition, the improvement by surfactant was limited, but under harsh conditions surfactant indeed could enhance cellulose conversion. It was proposed that non-ionic surfactants could interact with substrates and cellulases to impact the adsorption behaviors of cellulases. Therefore, the beneficial action of surfactants on pure cellulose hydrolysis is influenced by hydrolysis condition, cellulose structural features and cellulase formulation.
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Affiliation(s)
- Yan Zhou
- Institute of Applied Chemistry, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Hongmei Chen
- Institute of Applied Chemistry, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
| | - Feng Qi
- College of Life Sciences/Engineering Research Center of Industrial Microbiology, Fujian Normal University, Fuzhou 350108, China
| | - Xuebing Zhao
- Institute of Applied Chemistry, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
| | - Dehua Liu
- Institute of Applied Chemistry, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
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21
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Gomes D, Rodrigues AC, Domingues L, Gama M. Cellulase recycling in biorefineries—is it possible? Appl Microbiol Biotechnol 2015; 99:4131-43. [DOI: 10.1007/s00253-015-6535-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/09/2015] [Accepted: 03/11/2015] [Indexed: 11/28/2022]
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22
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Hickert LR, Cruz MM, Dillon AJP, Fontana RC, Rosa CA, Ayub MAZ. Fermentation kinetics of acid–enzymatic soybean hull hydrolysate in immobilized-cell bioreactors of Saccharomyces cerevisiae, Candida shehatae, Spathaspora arborariae, and their co-cultivations. Biochem Eng J 2014. [DOI: 10.1016/j.bej.2014.04.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Rosales-Calderon O, Trajano HL, Duff SJB. Stability of commercial glucanase and β-glucosidase preparations under hydrolysis conditions. PeerJ 2014; 2:e402. [PMID: 24949230 PMCID: PMC4060035 DOI: 10.7717/peerj.402] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 05/07/2014] [Indexed: 11/20/2022] Open
Abstract
The cost of enzymes makes enzymatic hydrolysis one of the most expensive steps in the production of lignocellulosic ethanol. Diverse studies have used commercial enzyme cocktails assuming that change in total protein concentration during hydrolysis was solely due to adsorption of endo- and exoglucanases onto the substrate. Given the sensitivity of enzymes and proteins to media conditions this assumption was tested by evaluating and modeling the protein concentration of commercial cocktails at hydrolysis conditions. In the absence of solid substrate, the total protein concentration of a mixture of Celluclast 1.5 L and Novozyme 188 decreased by as much as 45% at 50 °C after 4 days. The individual cocktails as well as a mixture of both were stable at 20 °C. At 50 °C, the protein concentration of Celluclast 1.5 was relatively constant but Novozyme 188 decreased by as much as 77%. It was hypothesized that Novozyme 188 proteins suffer a structural change at 50 °C which leads to protein aggregation and precipitation. Lyophilized β-glucosidase (P-β-glucosidase) at 50 °C exhibited an aggregation rate which was successfully modeled using first order kinetics (R2 = 0.97). By incorporating the possible presence of chaperone proteins in Novozyme 188, the protein aggregation observed for this cocktail was successfully modeled (R2 = 0.96). To accurately model the increasing protein stability observed at high cocktail loadings, the model was modified to include the presence of additives in the cocktail (R2 = 0.98). By combining the measurement of total protein concentration with the proposed Novozyme 188 protein aggregation model, the endo- and exoglucanases concentration in the solid and liquid phases during hydrolysis can be more accurately determined. This methodology can be applied to various systems leading to optimization of enzyme loading by minimizing the excess of endo- and exoglucanases. In addition, the monitoring of endo- and exoglucanases concentrations can be used to build mass balances of enzyme recycling processes and to techno-economically evaluate the viability of enzyme recycling.
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Affiliation(s)
- Oscar Rosales-Calderon
- Department of Chemical and Biological Engineering, The University of British Columbia , Vancouver, BC , Canada
| | - Heather L Trajano
- Department of Chemical and Biological Engineering, The University of British Columbia , Vancouver, BC , Canada
| | - Sheldon J B Duff
- Department of Chemical and Biological Engineering, The University of British Columbia , Vancouver, BC , Canada
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24
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Shang Y, Su R, Huang R, Yang Y, Qi W, Li Q, He Z. Recycling cellulases by pH-triggered adsorption-desorption during the enzymatic hydrolysis of lignocellulosic biomass. Appl Microbiol Biotechnol 2014; 98:5765-74. [DOI: 10.1007/s00253-014-5761-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 04/05/2014] [Accepted: 04/07/2014] [Indexed: 11/30/2022]
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25
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Gong Z, Shen H, Yang X, Wang Q, Xie H, Zhao ZK. Lipid production from corn stover by the oleaginous yeast Cryptococcus curvatus. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:158. [PMID: 25352914 PMCID: PMC4210566 DOI: 10.1186/s13068-014-0158-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 10/08/2014] [Indexed: 05/05/2023]
Abstract
BACKGROUND Microbial lipids produced from lignocellulosic biomass hold great promise for the biodiesel industry. These lipids usually consist of three major processes: pretreatment, enzymatic hydrolysis and lipid production. However, the conventional strategy of using biomass hydrolysates as the feedstock for lipid production suffers from low lipid coefficient and prohibitively high costs. More cost-effective and integrated processes are required to advance lignocellulosic biomass-based microbial lipid technology. RESULTS Three different strategies were tested using the oleaginous yeast Cryptococcus curvatus ATCC 20509 as a lipid producer and alkaline-pretreated corn stover as a model material. It was found that the separate hydrolysis and enhanced lipid production process required more cellulolytic enzymes yet afforded a low lipid coefficient of 115.6 mg/g pretreated corn stover. When biomass hydrolysis and lipid production were integrated, the amounts of cellulase and xylanase were reduced and no β-glucosidase was required. The simultaneous saccharification and lipid production process gave a lipid coefficient of 129.4 mg/g pretreated corn stover. A higher lipid coefficient of 159.4 mg/g pretreated corn stover was obtained using the simultaneous saccharification and enhanced lipid production (SSELP) process. Furthermore, cellulolytic enzymes were found recoverable and reusable upon recycling the spent supernatants of the SSELP process, which could reduce enzyme consumption and wastewater discharge. CONCLUSIONS The SSELP process was superior to other processes in terms of converting alkaline-pretreated corn stover into lipids by C. curvatus, as it required less cellulolytic enzymes and had a higher lipid coefficient. Moreover, the process facilitated easy enzyme recycling that should lead to further reduction of enzyme consumption. These results provide valuable information for cost-effective lipid production from lignocelluloses, which should be particularly important in achieving a sustainable production of biodiesel.
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Affiliation(s)
- Zhiwei Gong
- />Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 China
- />College of Chemical Engineering and Technology, Wuhan University of Science and Technology, 947 Heping Road, Wuhan, 430081 China
| | - Hongwei Shen
- />Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 China
- />Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 PR China
| | - Xiaobing Yang
- />Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 China
| | - Qian Wang
- />Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 China
- />Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 PR China
| | - Haibo Xie
- />Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 China
- />Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 PR China
| | - Zongbao K Zhao
- />Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 China
- />Division of Biotechnology, Dalian Institute of Chemical Physics, CAS, 457 Zhongshan Road, Dalian, 116023 PR China
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26
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Yu Z, Jameel H, Chang HM, Philips R, Park S. Quantification of bound and free enzymes during enzymatic hydrolysis and their reactivities on cellulose and lignocellulose. BIORESOURCE TECHNOLOGY 2013; 147:369-377. [PMID: 23999266 DOI: 10.1016/j.biortech.2013.08.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 07/29/2013] [Accepted: 08/02/2013] [Indexed: 05/16/2023]
Abstract
Enzymatic hydrolysis of insoluble biomass is a surface reaction. Part of the enzyme adsorb on the surface of biomass, whereas the others stay in the liquid phase. In this study, three substrates (Avicel cellulose, bleached hardwood pulp, and green-liquor pretreated hardwood pulp) were used to study the reactivity of bound and free enzyme. In a continuous enzymatic hydrolysis, 35-65% initially added enzymes became bound enzymes, which were primarily responsible for enzymatic hydrolysis. The contribution from free enzymes became insignificant after a certain period of reaction time. SDS-PAGE analysis showed that CBH I was significantly decreased in the free enzyme, which might be the reason for the low digestibility of free enzymes due to the loss of synergistic effect. When Tween 80 was added during enzymatic hydrolysis, the digestibility of free enzyme on Avicel was greatly enhanced. However, the benefit of surfactant was not noticeable for lignocellulosic pulps, comparing to Avicel.
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Affiliation(s)
- Zhiying Yu
- Department of Forest Biomaterials, North Carolina State University, Raleigh, NC 27695, USA
| | - Hasan Jameel
- Department of Forest Biomaterials, North Carolina State University, Raleigh, NC 27695, USA
| | - Hou-Min Chang
- Department of Forest Biomaterials, North Carolina State University, Raleigh, NC 27695, USA
| | - Richard Philips
- Department of Forest Biomaterials, North Carolina State University, Raleigh, NC 27695, USA
| | - Sunkyu Park
- Department of Forest Biomaterials, North Carolina State University, Raleigh, NC 27695, USA.
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27
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Ouyang J, Liu B, Zhang M, Zheng Z, Yu H. Enzymatic hydrolysis, adsorption, and recycling during hydrolysis of bagasse sulfite pulp. BIORESOURCE TECHNOLOGY 2013; 146:288-293. [PMID: 23948265 DOI: 10.1016/j.biortech.2013.07.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/05/2013] [Accepted: 07/06/2013] [Indexed: 06/02/2023]
Abstract
The high costs of enzymatic hydrolysis along with the high enzyme dosage are often considered as the major bottlenecks in lignocellulosic bioconversion. This study investigated the hydrolysis efficiency, cellulase adsorption and enzyme recycling during the hydrolysis of bagasse sulfite pulp (BSP). After 48 h of hydrolysis, more than 70% of the cellulose was hydrolyzed, while the protein concentration and cellulase activity in solution remained 31% and 17% of the initial value, respectively. The cellulase adsorption on the fresh BSP was better fitted by a Sips model, suggesting the occurrence of a multilayer adsorption at low cellulase concentration and monolayer adsorption at high concentration on the BSP surfaces. Desorption profile studies showed that the optimum desorption condition was at pH 4.8 and 40 °C. Moreover, considering the limited ability to desorption, directly empolying the bound enzyme with residual substrate is more effective method to recover cellulase during the hydrolysis of BSP.
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Affiliation(s)
- Jia Ouyang
- Jiangsu Key Lab of Biomass-Based Green Fuels and Chemicals, Nanjing 210037, People's Republic of China.
| | - Baotian Liu
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Min Zhang
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Zhaojuan Zheng
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
| | - Heng Yu
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, People's Republic of China
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28
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The challenging measurement of protein in complex biomass-derived samples. Appl Biochem Biotechnol 2013; 172:87-101. [PMID: 24046255 DOI: 10.1007/s12010-013-0466-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 08/22/2013] [Indexed: 10/26/2022]
Abstract
Measurement of the protein content in samples from production of lignocellulosic bioethanol is an important tool when studying the adsorption of cellulases. Several methods have been used for this, and after reviewing the literature, we concluded that one of the most promising assays for simple and fast protein measurement on this type of samples was the ninhydrin assay. This method has also been used widely for this purpose, but with two different methods for protein hydrolysis prior to the assay-alkaline or acidic hydrolysis. In samples containing glucose or ethanol, there was significant interference from these compounds when using acid hydrolysis, which was not the case when using the alkaline hydrolysis. We evaluated the interference from glucose, cellulose, xylose, xylan, lignin and ethanol on protein determination of BSA, Accellerase(®) 1500 and Cellic(®) CTec2. The experiments demonstrated that the presence of cellulose, lignin and glucose (above 50 g/kg) could significantly affect the results of the assay. Comparison of analyses performed with the ninhydrin assay and with a CN analyser revealed that there was good agreement between these two analytical methods, but care has to be taken when applying the ninhydrin assay. If used correctly, the ninhydrin assay can be used as a fast method to evaluate the adsorption of cellulases to lignin.
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29
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Weiss N, Börjesson J, Pedersen LS, Meyer AS. Enzymatic lignocellulose hydrolysis: Improved cellulase productivity by insoluble solids recycling. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:5. [PMID: 23336604 PMCID: PMC3560254 DOI: 10.1186/1754-6834-6-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Accepted: 01/11/2013] [Indexed: 05/18/2023]
Abstract
BACKGROUND It is necessary to develop efficient methods to produce renewable fuels from lignocellulosic biomass. One of the main challenges to the industrialization of lignocellulose conversion processes is the large amount of cellulase enzymes used for the hydrolysis of cellulose. One method for decreasing the amount of enzyme used is to recycle the enzymes. In this study, the recycle of enzymes associated with the insoluble solid fraction after the enzymatic hydrolysis of cellulose was investigated for pretreated corn stover under a variety of recycling conditions. RESULTS It was found that a significant amount of cellulase activity could be recovered by recycling the insoluble biomass fraction, and the enzyme dosage could be decreased by 30% to achieve the same glucose yields under the most favorable conditions. Enzyme productivity (g glucose produced/g enzyme applied) increased between 30 and 50% by the recycling, depending on the reaction conditions. While increasing the amount of solids recycled increased process performance, the methods applicability was limited by its positive correlation with increasing total solids concentrations, reaction volumes, and lignin content of the insoluble residue. However, increasing amounts of lignin rich residue during the recycle did not negatively impact glucose yields. CONCLUSIONS To take advantage of this effect, the amount of solids recycled should be maximized, based on a given processes ability to deal with higher solids concentrations and volumes. Recycling of enzymes by recycling the insoluble solids fraction was thus shown to be an effective method to decrease enzyme usage, and research should be continued for its industrial application.
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Affiliation(s)
- Noah Weiss
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark (DTU), Lyngby, DK-2800 Kgs, Denmark
| | | | | | - Anne S Meyer
- Center for Bioprocess Engineering, Department of Chemical and Biochemical Engineering, Technical University of Denmark (DTU), Lyngby, DK-2800 Kgs, Denmark
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30
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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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31
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Seo DJ, Fujita H, Sakoda A. Structural changes of lignocelluloses by a nonionic surfactant, Tween 20, and their effects on cellulase adsorption and saccharification. BIORESOURCE TECHNOLOGY 2011; 102:9605-12. [PMID: 21852116 DOI: 10.1016/j.biortech.2011.07.034] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Revised: 07/02/2011] [Accepted: 07/12/2011] [Indexed: 05/16/2023]
Abstract
In this work, we found that Tween 20 treatment (0-8 mM) contributed to the cell wall collapse of most samples except for those with high lignin contents and high crystallinity. Cell wall collapse contributed to the formation of 10- to 50-nm pores and not only increased the monolayer saturation amount of adsorbed cellulase about 3-3.6 times but also increased the cellulase adsorption rate (D(e)/r(2)) about 160-880 times. Moreover, cellulose conversion at 72 h was also increased 8.7-21.5% by Tween 20 treatment. On the other hand, the adsorption of Tween 20 on Avicel (microcrystalline cellulose) hindered the cellulase reaction (adsorption and saccharification). The effect of Tween 20 treatment on the crystalline part was insignificant for both lignocelluloses and Avicel. It was found that some degree of pretreatment (e.g. lignin removal) that enhances Tween 20 diffusion into samples is necessary to obtain the structural effects of Tween 20.
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Affiliation(s)
- Dong-June Seo
- Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Tokyo 153-8505, Japan.
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32
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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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33
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Geddes CC, Nieves IU, Ingram LO. Advances in ethanol production. Curr Opin Biotechnol 2011; 22:312-9. [DOI: 10.1016/j.copbio.2011.04.012] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 04/18/2011] [Indexed: 12/23/2022]
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The Effect of Gleditsia Saponin on Simultaneous Saccharification and Fermentation of Furfural Residue for Ethanol Production. ACTA ACUST UNITED AC 2011. [DOI: 10.4028/www.scientific.net/amr.236-238.108] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Simultaneous saccharification and fermentation is an attractive process configuration for bioethanol. However, the process cost in SSF is still high. Further reductions in cost are expected with reduction of enzyme addition and the use of waste agricultural or industrial materials as feedstock. Surfactant addition is a simple method to reduce the amount of enzyme loading. In the present work we explore the effect of Gleditsia Saponin, an inexpensive and natural surfactant, on SSF of furfural residue, a main waste of furfural industry in China, for ethanol production. Gleditsia Saponin addition even at low concentration, 0.04 g/l, increased the ethanol yield by 9.9%. Meanwhile, when Gleditsia Saponin addition was 0.16 g/l, the yield was increased by 22.8% and the enzyme activity significantly increased in the liquid fraction at the end of SSF, which would contribute to recover and recycle enzyme. Gleditsia Saponin addition at 1.25 g/l had a better performance in improving SSF efficiency than that of 2.5 g/l Tween-20 addition. The positive effects of Gleditsia Saponin addition on SSF, such as less enzyme loading and shorter residence time could also been observed.
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Hydrolytic Enzyme of Cellulose for Complex Formulation Applied Research. Appl Biochem Biotechnol 2010; 164:23-33. [DOI: 10.1007/s12010-010-9111-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 10/11/2010] [Indexed: 11/26/2022]
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Characterization of commercial cellulases and their use in the saccharification of a sugarcane bagasse sample pretreated with dilute sulfuric acid. J Ind Microbiol Biotechnol 2010; 38:1089-98. [DOI: 10.1007/s10295-010-0888-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2010] [Accepted: 09/29/2010] [Indexed: 10/18/2022]
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Hydrolysis efficiency and enzyme adsorption on steam-pretreated spruce in the presence of poly(ethylene glycol). Enzyme Microb Technol 2010. [DOI: 10.1016/j.enzmictec.2010.05.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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