1
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Efficient substrate accessibility of cross-linked levanase aggregates using dialdehyde starch as a macromolecular cross-linker. Carbohydr Polym 2021; 267:118159. [PMID: 34119133 DOI: 10.1016/j.carbpol.2021.118159] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 04/18/2021] [Accepted: 04/19/2021] [Indexed: 11/22/2022]
Abstract
Cross-linked enzyme aggregates (CLEAs) are influenced by mass diffusion limitations such as the degree of molecular cross-linking attained, which affects substrate accessibility. Thus, this study seeks to improve substrate accessibility using macromolecular cross-linkers in cross-linked levanase aggregates (CLLAs) formation for levan-type fructooligosaccharides (L-FOS) production. Dialdehyde starch-tapioca (DAST) was successfully developed and used to cross-link levanase to form CLLAs-D and with bovine serum albumin (BSA) to form CLLAs-DB which showed activity recoveries of 65.6% and 81.6%, respectively. After cross-linking, the pH (6-10) and thermal stability (30-40 °C) increased, and organic solvent tolerance resulted in the activation of CLLAs. Likewise, CLLAs-DB had higher substrate affinity and accessibility and a higher effectiveness factors than CLLAs-D. The total L-FOS yield of CLLAs-DB (78.9% (w/v)) was higher than that of CLLAs-D (62.4% (w/v)). Therefore, as a cross-linker, DAST may have application prospects as a promising and green biocatalyst for product formation.
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2
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Fu H, Mo W, Shen X, Li B. Impact of centrifugation treatment on enzymatic hydrolysis of cellulose and xylan in poplar fibers with high lignin content. BIORESOURCE TECHNOLOGY 2020; 316:123866. [PMID: 32745999 DOI: 10.1016/j.biortech.2020.123866] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 06/11/2023]
Abstract
Centrifugation is very common in the production and treatment of lignocellulose for applications like pretreatment for enzymatic hydrolysis, but it is not certain whether it affects applications of lignocellulose and almost no one realizes this problem. This study investigated the effects of centrifugation on the characteristics and enzymatic hydrolysis of poplar fibers with high lignin content. The results showed that centrifugation inhibited the enzymatic hydrolysis of fiber, but fiber characteristics and enzymatic digestibility fluctuated with increasing centrifugation time. Centrifugation for about 15 min had the least effect on fiber properties while centrifugation for 30 min had the least effect on enzymatic hydrolysis. The water retention value was closely related to the enzymatic digestibility, but the pore characteristics and crystallinity index could not reflect the enzymatic accessibility of the fiber. This article will provide useful references for the enzymatic hydrolysis of lignocellulose and other high-value applications to improve production efficiency furtherly.
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Affiliation(s)
- Hongkang Fu
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640, China
| | - Wenxuan Mo
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640, China
| | - Xiaoning Shen
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640, China
| | - Bo Li
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640, China.
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3
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Digaitis R, Thybring EE, Thygesen LG. Investigating the role of mechanics in lignocellulosic biomass degradation during hydrolysis: Part II. Biotechnol Prog 2020; 37:e3083. [PMID: 32935452 PMCID: PMC7988658 DOI: 10.1002/btpr.3083] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/28/2020] [Accepted: 09/14/2020] [Indexed: 11/29/2022]
Abstract
Lignocellulose breakdown in biorefineries is facilitated by enzymes and physical forces. Enzymes degrade and solubilize accessible lignocellulosic polymers, primarily on fiber surfaces, and make fibers physically weaker. Meanwhile physical forces acting during mechanical agitation induce tearing and cause rupture and attrition of the fibers, leading to liquefaction, that is, a less viscous hydrolysate that can be further processed in industrial settings. This study aims at understanding how mechanical agitation during enzymatic saccharification can be used to promote fiber attrition. The effects of reaction conditions, such as substrate and enzyme concentration on fiber attrition rate and hydrolysis yield were investigated. To gain insight into the fiber attrition mechanism, enzymatic hydrolysis was compared to hydrolysis by use of hydrochloric acid. Results show that fiber attrition depends on several factors concerning reactor design and operation including drum diameter, rotational speed, mixing schedule, and concentrations of fibers and enzymes. Surprisingly, different fiber attrition patterns during enzymatic and acid hydrolysis were found for similar mixing schedules. Specifically, for tumbling mixing, slow continuous mixing appears to function better than faster, intermittent mixing even for the same total number of drum revolutions. The findings indicate that reactor design and operation as well as hydrolysis conditions are key to process optimization and that detailed insights are needed to obtain fast liquefaction without sacrificing saccharification yields.
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Affiliation(s)
- Ramūnas Digaitis
- Department of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen, Frederiksberg C, Denmark.,Biofilms Research Center for Biointerfaces, Malmö University, Malmö, Sweden
| | - Emil Engelund Thybring
- Department of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen, Frederiksberg C, Denmark
| | - Lisbeth Garbrecht Thygesen
- Department of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen, Frederiksberg C, Denmark
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4
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Abd Rahman NH, Jaafar NR, Abdul Murad AM, Abu Bakar FD, Shamsul Annuar NA, Md Illias R. Novel cross-linked enzyme aggregates of levanase from Bacillus lehensis G1 for short-chain fructooligosaccharides synthesis: Developmental, physicochemical, kinetic and thermodynamic properties. Int J Biol Macromol 2020; 159:577-589. [DOI: 10.1016/j.ijbiomac.2020.04.262] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 10/24/2022]
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5
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Xu Q, Qin J, Yuan T, Ko JH. Extracellular enzyme and microbial activity in MSW landfills with different gas collection and leachate management practices. CHEMOSPHERE 2020; 250:126264. [PMID: 32105861 DOI: 10.1016/j.chemosphere.2020.126264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 02/04/2020] [Accepted: 02/17/2020] [Indexed: 06/10/2023]
Abstract
The performance of simulated municipal solid waste (MSW) landfills with two different biogas collection practices - (1) upward and upward-downward biogas flow collection (LT-TB) in sequence and (2) simultaneous upward-downward biogas flow collection (LTB) from the beginning of the anaerobic degradation process - was investigated in terms of landfill gas and leachate, enzyme activity, and microbial community structure associated with MSW compression and leachate recirculation. The cumulative methane volume in LTB was 1.5 times higher than that in LT-TB. With MSW compression and leachate recirculation, amylase and lipase activity were enhanced in LTB. In LT-TB, the activities gradually decreased after reaching a peak with compression. The two biogas collection strategies influenced the community structure and activity of bacteria and archaea. The upward and downward gas collection flow with waste compression and leachate recirculation improved the environment for enriching bacterial phyla Firmicutes, Proteobacteria, and Synergistetes and genus Methanosarcina in Archaea.
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Affiliation(s)
- Qiyong Xu
- Key Laboratory for Eco-efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Guangdong, 518055, China
| | - Jie Qin
- Key Laboratory for Eco-efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Guangdong, 518055, China
| | - Tugui Yuan
- Key Laboratory for Eco-efficient Recycled Materials, School of Environment and Energy, Peking University Shenzhen Graduate School, Guangdong, 518055, China
| | - Jae Hac Ko
- Department of Environmental Engineering, College of Ocean Sciences, Jeju National University, Jeju Special Self-Governing Province, 63243, Republic of Korea.
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6
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Tobin T, Gustafson R, Bura R, Gough HL. Integration of wastewater treatment into process design of lignocellulosic biorefineries for improved economic viability. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:24. [PMID: 32025241 PMCID: PMC6998191 DOI: 10.1186/s13068-020-1657-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 01/16/2020] [Indexed: 06/02/2023]
Abstract
BACKGROUND Production and use of bio-based products offer advantages over conventional petrochemicals, yet the relatively high cost of production has restricted their mainstream adoption. Optimization of wastewater treatment processes could reduce capital expenditures, lowering the barrier to market entry for lignocellulosic biorefineries. This paper characterizes wastewater associated with lignocellulosic ethanol production and evaluates potential wastewater treatment operations. RESULTS It is found that organic material is intrinsic to bioconversion wastewater, representing up to 260 kg of biological oxygen demand per tonne of feedstock processed. Inorganics in the wastewater largely originate from additions during pretreatment and pH adjustments, which increase the inorganic loading by 44 kg per tonne of feedstock processed. Adjusting the ethanol production process to decrease addition of inorganic material could reduce the demands and therefore cost of waste treatment. Various waste treatment technologies-including those that take advantage of ecosystem services provided by feedstock production-were compared in terms of capital and operating costs, as well as technical feasibility. CONCLUSIONS It is concluded that wastewater treatment technologies should be better integrated with conversion process design and feedstock production. Efforts to recycle resources throughout the biofuel supply chain through application of ecosystem services provided by adjacent feedstock plantations and recovery of resources from the waste stream to reduce overall capital and operating costs of bioconversion facilities.
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Affiliation(s)
- Tyler Tobin
- The School of Environmental and Forest Sciences, University of Washington, 4000 15th Avenue NE, Seattle, WA 98195-2100 USA
| | - Rick Gustafson
- The School of Environmental and Forest Sciences, University of Washington, 4000 15th Avenue NE, Seattle, WA 98195-2100 USA
| | - Renata Bura
- The School of Environmental and Forest Sciences, University of Washington, 4000 15th Avenue NE, Seattle, WA 98195-2100 USA
| | - Heidi L. Gough
- The School of Environmental and Forest Sciences, University of Washington, 4000 15th Avenue NE, Seattle, WA 98195-2100 USA
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7
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Gaikwad A, Meshram A. Effect of particle size and mixing on the laccase-mediated pretreatment of lignocellulosic biomass for enhanced saccharification of cellulose. CHEM ENG COMMUN 2019. [DOI: 10.1080/00986445.2019.1680364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Ashwin Gaikwad
- Visvesvaraya National Institute of Technology, Nagpur, India
| | - Anjali Meshram
- Visvesvaraya National Institute of Technology, Nagpur, India
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8
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Gatt E, Khatri V, Bley J, Barnabé S, Vandenbossche V, Beauregard M. Enzymatic hydrolysis of corn crop residues with high solid loadings: New insights into the impact of bioextrusion on biomass deconstruction using carbohydrate-binding modules. BIORESOURCE TECHNOLOGY 2019; 282:398-406. [PMID: 30884460 DOI: 10.1016/j.biortech.2019.03.045] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 06/09/2023]
Abstract
Lignocellulosic biomass is a sustainable source of renewable substrate to produce low carbon footprint energy and materials. Biomass conversion is usually performed in two steps: a biomass pretreatment for improving cellulose accessibility followed by enzymatic hydrolysis of cellulose. In this study we investigated the efficiency of a bioextrusion pretreatment (extrusion in the presence of cellulase enzyme) for production of reducing sugars from corn crop agricultural residues. Our results demonstrate that bioextrusion increased the reducing sugar conversion yield by at least 94% at high solid/liquid ratio (14%-40%). Monitoring biomass surface with carbohydrate-binding modules (FTCM-depletion assay) revealed that well known negative impact of high solid/liquid ratio on conversion yield is not due to the lack of exposed cellulose which was abundant under such conditions. Bioextrusion was found to be less efficient on alkaline pretreated biomass but being a mild and solvent limiting pretreatment, it might help to minimize the waste stream.
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Affiliation(s)
- Etienne Gatt
- Laboratoire de Chimie Agro-industrielle, LCA, Université de Toulouse, INRA, Toulouse, France.
| | - Vinay Khatri
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada; PROTEO, Université Laval, Québec G1V 4G2, Canada.
| | - Julien Bley
- Centre de recherche sur les matériaux lignocellulosiques, Université du Québec à Trois-Rivières, Canada; Innofibre, 3351 Boulevard des Forges, Québec G9A 5E6, Canada
| | - Simon Barnabé
- Centre de recherche sur les matériaux lignocellulosiques, Université du Québec à Trois-Rivières, Canada
| | - Virginie Vandenbossche
- Laboratoire de Chimie Agro-industrielle, LCA, Université de Toulouse, INRA, Toulouse, France.
| | - Marc Beauregard
- Centre de recherche sur les matériaux lignocellulosiques, Université du Québec à Trois-Rivières, Canada; PROTEO, Université Laval, Québec G1V 4G2, Canada
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9
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Fuzzy-Enhanced Modeling of Lignocellulosic Biomass Enzymatic Saccharification. ENERGIES 2019. [DOI: 10.3390/en12112110] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The enzymatic hydrolysis of lignocellulosic biomass incorporates many physico-chemical phenomena, in a heterogeneous and complex media. In order to make the modeling task feasible, many simplifications must be assumed. Hence, different simplified models, such as Michaelis-Menten and Langmuir-based ones, have been used to describe batch processes. However, these simple models have difficulties in predicting fed-batch operations with different feeding policies. To overcome this problem and avoid an increase in the complexity of the model by incorporating other phenomenological terms, a Takagi-Sugeno Fuzzy approach has been proposed, which manages a consortium of different simple models for this process. Pretreated sugar cane bagasse was used as biomass in this case study. The fuzzy rule combines two Michaelis-Menten-based models, each responsible for describing the reaction path for a distinct range of solids concentrations in the reactor. The fuzzy model improved fitting and increased prediction in a validation data set.
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10
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Digaitis R, Thybring EE, Thygesen LG. Investigating the role of mechanics in lignocellulosic biomass degradation during hydrolysis. Biotechnol Prog 2018; 35:e2754. [PMID: 30468315 DOI: 10.1002/btpr.2754] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 10/13/2018] [Accepted: 11/20/2018] [Indexed: 11/12/2022]
Abstract
Enzymes and mechanics play major roles in lignocellulosic biomass deconstruction in biorefineries by catalyzing chemical cleavage or inducing physical breakdown of biomass, respectively. At industrially relevant substrate concentrations mechanical agitation is also a driving force for mass transfer as well as agglomeration of elongated biomass particles. Contrary to the physically induced particle attrition, which typically facilitates feedstock handling, particle agglomeration tends to hinder mass transfer and in the worst case induces processing difficulties like pipe blockage. Understanding the complex interplay between mechanical agitation and enzymatic degradation during hydrolysis is therefore critical and was the aim of this study. Particle size analyses revealed that neither mechanical agitation alone nor enzymatic treatment without mechanical agitation had any noteworthy effect on flax fiber attrition. Similarly, successive treatment, where mechanical agitation was either preceded or proceeded by enzymatic hydrolysis, did not induce any substantial segmentation of flax fibers. Simultaneous enzymatic and mechanical treatment on the other hand was found to promote fast fiber shortening. Higher hydrolysis yields, however, were obtained from nonagitated samples after prolonged enzymatic treatment, indicating that mechanical agitation in the long run reduces activity of the cellulolytic enzymes. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 35: e2754, 2019.
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Affiliation(s)
- Ramūnas Digaitis
- Dept. of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen, Rolighedsvej 23, Frederiksberg C, Denmark
| | - Emil Engelund Thybring
- Dept. of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen, Rolighedsvej 23, Frederiksberg C, Denmark
| | - Lisbeth Garbrecht Thygesen
- Dept. of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen, Rolighedsvej 23, Frederiksberg C, Denmark
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11
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Wiedemann L, Conti F, Saidi A, Sonnleitner M, Goldbrunner M. Modeling Mixing in Anaerobic Digesters with Computational Fluid Dynamics Validated by Experiments. Chem Eng Technol 2018. [DOI: 10.1002/ceat.201800083] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Leonhard Wiedemann
- Technische Hochschule Ingolstadt; Institute of new Energy Systems; Esplanade 10 85049 Ingolstadt Germany
| | - Fosca Conti
- Technische Hochschule Ingolstadt; Institute of new Energy Systems; Esplanade 10 85049 Ingolstadt Germany
- University of Padova; Department of Chemical Sciences; via Marzolo 1 35141 Padova Italy
| | - Abdessamad Saidi
- Technische Hochschule Ingolstadt; Institute of new Energy Systems; Esplanade 10 85049 Ingolstadt Germany
| | - Matthias Sonnleitner
- Technische Hochschule Ingolstadt; Institute of new Energy Systems; Esplanade 10 85049 Ingolstadt Germany
| | - Markus Goldbrunner
- Technische Hochschule Ingolstadt; Institute of new Energy Systems; Esplanade 10 85049 Ingolstadt Germany
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12
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Dutta SK, Chakraborty S. Mixing effects on the kinetics and the dynamics of two-phase enzymatic hydrolysis of hemicellulose for biofuel production. BIORESOURCE TECHNOLOGY 2018; 259:276-285. [PMID: 29571171 DOI: 10.1016/j.biortech.2018.03.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/07/2018] [Accepted: 03/08/2018] [Indexed: 06/08/2023]
Abstract
This work uses a coupled experimental and modeling approach to explore the effects of macro- and micro-mixing on the kinetics and the dynamics of two-phase enzymatic hydrolysis of hemicellulose. Reactor mixing does not alter the non-competitive nature of product inhibition in hemicellulose hydrolysis by endoxylanase, but produces stronger inhibition that reduces the soluble sugar yield by 8-14.5%, as the mixing speed increases from 0 to 200 rpm. The kinetic constants (Km, Vmax, Kx) assume mass-transfer disguised values at 0-200 rpm. An optimal mixing strategy, comprising of 55-70 min of initial rapid convective macromixing followed by diffusive micromixing (without any macromixing) for the rest of the hydrolysis, increases xylose and reducing sugar yields by 6.3-8% and 13-20%, respectively, over continuous mixing at 200 rpm, for 1-5 mg/ml substrate loading at an optimum enzyme to substrate ratio of 1:20, with an energy saving of 94-96% over 24 h.
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Affiliation(s)
- Sajal Kanti Dutta
- Department of Chemical Engineering, Indian Institute of Technology, Kharagpur 721302, India
| | - Saikat Chakraborty
- Department of Chemical Engineering, Indian Institute of Technology, Kharagpur 721302, India; School of Energy Science and Engineering, Indian Institute of Technology, Kharagpur 721302, India.
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13
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Gaikwad A. Interactions of mixing and reaction kinetics of depolymerization of cellulose to renewable fuels. CHEM ENG COMMUN 2017. [DOI: 10.1080/00986445.2017.1371015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Ashwin Gaikwad
- Department of Chemical Engineering, Visvesvaraya National Institute of Technology, Nagpur, India
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14
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Chakraborty S, Singh PK, Paramashetti P. Microreactor-based mixing strategy suppresses product inhibition to enhance sugar yields in enzymatic hydrolysis for cellulosic biofuel production. BIORESOURCE TECHNOLOGY 2017; 237:99-107. [PMID: 28389042 DOI: 10.1016/j.biortech.2017.03.152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 03/23/2017] [Accepted: 03/24/2017] [Indexed: 06/07/2023]
Abstract
A novel microreactor-based energy-efficient process of using complete convective mixing in a macroreactor till an optimal mixing time followed by no mixing in 200-400μl microreactors enhances glucose and reducing sugar yields by upto 35% and 29%, respectively, while saving 72-90% of the energy incurred on reactor mixing in the enzymatic hydrolysis of cellulose. Empirical exponential relations are provided for determining the optimal mixing time, during which convective mixing in the macroreactor promotes mass transport of the cellulase enzyme to the solid Avicel substrate, while the latter phase of no mixing in the microreactor suppresses product inhibition by preventing the inhibitors (glucose and cellobiose) from homogenizing across the reactor. Sugar yield increases linearly with liquid to solid height ratio (rh), irrespective of substrate loading and microreactor size, since large rh allows the inhibitors to diffuse in the liquid away from the solids, thus reducing product inhibition.
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Affiliation(s)
- Saikat Chakraborty
- Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India.
| | - Prasun Kumar Singh
- Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
| | - Pawan Paramashetti
- Department of Chemical Engineering, Indian Institute of Technology Kharagpur, Kharagpur 721302, India
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15
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Tervasmäki P, Sotaniemi V, Kangas J, Taskila S, Ojamo H, Tanskanen J. A discretized model for enzymatic hydrolysis of cellulose in a fed-batch process. BIORESOURCE TECHNOLOGY 2017; 227:112-124. [PMID: 28013127 DOI: 10.1016/j.biortech.2016.12.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 12/12/2016] [Accepted: 12/14/2016] [Indexed: 05/24/2023]
Abstract
In the enzymatic hydrolysis of cellulose, several phenomena have been proposed to cause a decrease in the reaction rate with increasing conversion. The importance of each phenomenon is difficult to distinguish from batch hydrolysis data. Thus, kinetic models for the enzymatic hydrolysis of cellulose often suffer from poor parameter identifiability. This work presents a model that is applicable to fed-batch hydrolysis by discretizing the substrate based on the feeding time. Different scenarios are tested to explain the observed decrease in reaction rate with increasing conversion, and comprehensive assessment of the parameter sensitivities is carried out. The proposed model performed well in the broad range of experimental conditions used in this study and when compared to literature data. Furthermore, the use of data from fed-batch experiments and discretization of the model substrate to populations was found to be very informative when assessing the importance of the rate-decreasing phenomena in the model.
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Affiliation(s)
- Petri Tervasmäki
- Chemical Process Engineering, Faculty of Technology, University of Oulu, P.O. Box 4300, FI-90014 Oulun yliopisto, Finland.
| | - Ville Sotaniemi
- Chemical Process Engineering, Faculty of Technology, University of Oulu, P.O. Box 4300, FI-90014 Oulun yliopisto, Finland
| | - Jani Kangas
- Chemical Process Engineering, Faculty of Technology, University of Oulu, P.O. Box 4300, FI-90014 Oulun yliopisto, Finland
| | - Sanna Taskila
- Chemical Process Engineering, Faculty of Technology, University of Oulu, P.O. Box 4300, FI-90014 Oulun yliopisto, Finland
| | - Heikki Ojamo
- Department of Biotechnology and Chemical Technology, School of Chemical Technology, Aalto University, P.O. Box 16100, 00076, Aalto, Finland
| | - Juha Tanskanen
- Chemical Process Engineering, Faculty of Technology, University of Oulu, P.O. Box 4300, FI-90014 Oulun yliopisto, Finland
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16
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Qin LZ, Chen HZ. Evaluation of growth age for the diverse conversion of Ficus carica L. cut branches using steam explosion. Process Biochem 2016. [DOI: 10.1016/j.procbio.2016.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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17
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Gaona A, Lawryshyn Y, Saville B. The Effect of Fed-Batch Operation and Rotational Speed on High-Solids Enzymatic Hydrolysis of Hardwood Substrates. Ind Biotechnol (New Rochelle N Y) 2015. [DOI: 10.1089/ind.2014.0031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Adriana Gaona
- Laboratory of Bioprocess and Enzyme Technology, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | - Yuri Lawryshyn
- Laboratory of Bioprocess and Enzyme Technology, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | - Bradley Saville
- Laboratory of Bioprocess and Enzyme Technology, Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
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18
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Ramos LP, da Silva L, Ballem AC, Pitarelo AP, Chiarello LM, Silveira MHL. Enzymatic hydrolysis of steam-exploded sugarcane bagasse using high total solids and low enzyme loadings. BIORESOURCE TECHNOLOGY 2015; 175:195-202. [PMID: 25459822 DOI: 10.1016/j.biortech.2014.10.087] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2014] [Revised: 10/16/2014] [Accepted: 10/17/2014] [Indexed: 05/15/2023]
Abstract
Hydrolysis of phosphoric acid-impregnated steam-treated sugarcane bagasse was pre-optimized using a face-centered central composite design in which the process variables were the substrate total solids (TS, %), agitation intensity (AI, rpm) and enzyme loading (EL, gg(-1)). Pretreatment was carried out at 180°C for 10min using cane bagasse with 50wt% moisture content containing 9.5mg of H3PO4 per gram of dry biomass. Hydrolyses were performed for 96h at 50°C using Cellic CTec2® and water-washed steam-treated substrates. The highest amount of fermentable sugars was obtained with 20wt% TS, producing 76.8gL(-1) of glucose equivalents, which corresponded to a total glucan conversion of 69.2wt% and to a theoretical net increase of 39% in ethanol production from the same sugarcane tonnage without considering the use of leaves, tops and the additional yields from C5 sugars.
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Affiliation(s)
- Luiz Pereira Ramos
- Research Center in Applied Chemistry (CEPESQ), Department of Chemistry, Federal University of Paraná, Curitiba, PR, Brazil; INCT in Energy & Environment, Department of Chemistry, Federal University of Paraná, Brazil.
| | - Larissa da Silva
- Research Center in Applied Chemistry (CEPESQ), Department of Chemistry, Federal University of Paraná, Curitiba, PR, Brazil
| | - Annielly Comelli Ballem
- Research Center in Applied Chemistry (CEPESQ), Department of Chemistry, Federal University of Paraná, Curitiba, PR, Brazil
| | - Ana Paula Pitarelo
- Research Center in Applied Chemistry (CEPESQ), Department of Chemistry, Federal University of Paraná, Curitiba, PR, Brazil
| | - Luana Marcele Chiarello
- Research Center in Applied Chemistry (CEPESQ), Department of Chemistry, Federal University of Paraná, Curitiba, PR, Brazil
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Rheology of Lignocellulose Suspensions and Impact of Hydrolysis: A Review. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2015; 149:325-57. [PMID: 25786712 DOI: 10.1007/10_2015_323] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
White biotechnologies have several challenges to overcome in order to become a viable industrial process. Achieving highly concentrated lignocellulose materials and releasing fermentable substrates, with controlled kinetics in order to regulate micro-organism activity, present major technical and scientific bottlenecks. The degradation of the main polymeric fractions of lignocellulose into simpler molecules is a prerequisite for an integrated utilisation of this resource in a biorefinery concept. The characterisation methods and the observations developed for rheology, morphology, etc., that are reviewed here are strongly dependent on the fibrous nature of lignocellulose, are thus similar or constitute a good approach to filamentous culture broths. This review focuses on scientific works related to the study of the rheological behaviour of lignocellulose suspensions and their evolution during biocatalysis. In order to produce the targeted molecules (synthon), the lignocellulose substrates are converted by enzymatic degradation and are then metabolised by micro-organisms. The dynamics of the mechanisms is limited by coupled phenomena between flow, heat and mass transfers in regard to diffusion (within solid and liquid phases), convection (mixing, transfer coefficients, homogeneity) and specific inhibitors (concentration gradients). As lignocellulose suspensions consist of long entangled fibres for the matrix of industrial interest, they exhibit diverse and complex properties linked to this fibrous character (rheological, morphological, thermal, mechanical and biochemical parameters). Among the main variables to be studied, the rheological behaviour of such suspensions appears to be determinant for process efficiency. It is this behaviour that will determine the equipment to be used and the strategies applied (substrate and biocatalysis feed, mixing, etc.). This review provides an overview of (i) the rheological behaviour of fibrous materials in suspension, (ii) the methods and experimental conditions for their measurements, (iii) the main models used and (iv) their evolution during biocatalytic reactions with a focus on enzymatic hydrolysis.
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Lebaz N, Cockx A, Spérandio M, Morchain J. Population balance approach for the modelling of enzymatic hydrolysis of cellulose. CAN J CHEM ENG 2014. [DOI: 10.1002/cjce.22088] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Noureddine Lebaz
- Toulouse White Biotechnology; 3 rue des satellites 31400 Toulouse France
- Université de Toulouse; INSA; UPS; INP; LISBP; 135 Avenue de Rangueil F-31077 Toulouse France
- INRA; UMR792 Ingénierie des Systèmes Biologiques et des Procédés; F-31400 Toulouse France
- CNRS; UMR5504; F-31400 Toulouse France
| | - Arnaud Cockx
- Université de Toulouse; INSA; UPS; INP; LISBP; 135 Avenue de Rangueil F-31077 Toulouse France
- INRA; UMR792 Ingénierie des Systèmes Biologiques et des Procédés; F-31400 Toulouse France
- CNRS; UMR5504; F-31400 Toulouse France
| | - Mathieu Spérandio
- Université de Toulouse; INSA; UPS; INP; LISBP; 135 Avenue de Rangueil F-31077 Toulouse France
- INRA; UMR792 Ingénierie des Systèmes Biologiques et des Procédés; F-31400 Toulouse France
- CNRS; UMR5504; F-31400 Toulouse France
| | - Jérôme Morchain
- Université de Toulouse; INSA; UPS; INP; LISBP; 135 Avenue de Rangueil F-31077 Toulouse France
- INRA; UMR792 Ingénierie des Systèmes Biologiques et des Procédés; F-31400 Toulouse France
- CNRS; UMR5504; F-31400 Toulouse France
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Kinnarinen T, Häkkinen A. Influence of enzyme loading on enzymatic hydrolysis of cardboard waste and size distribution of the resulting fiber residue. BIORESOURCE TECHNOLOGY 2014; 159:136-142. [PMID: 24650527 DOI: 10.1016/j.biortech.2014.02.091] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/21/2014] [Accepted: 02/22/2014] [Indexed: 06/03/2023]
Abstract
Enzymatic hydrolysis of lignocellulosic biomass to sugars alters the properties of the cellulosic fibers. Several process variables, including enzyme loading, play an important role in these changes. Many physical properties of fibers are affected: their length and width, porosity, specific surface area, and degree of fibrillation, for instance, may undergo dramatic changes when subjected to enzymatic degradation. In this study, the influence of enzyme loading on the fiber size was investigated using milled cardboard waste as the raw material. The effect of cellulases and hemicellulases on the monosaccharide production and the resulting fiber size was studied using commercial enzyme products. It was shown that the cellulase loading largely determined the amount of sugars produced. The fiber length was reduced during the course of hydrolysis, although the size reduction was not especially dramatic. Based on the SEM images, no significant damage to the fiber surfaces occurred during the process.
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Affiliation(s)
- Teemu Kinnarinen
- Laboratory of Separation Technology, LUT Chemistry, Lappeenranta University of Technology, P.O. Box 20, FI-53851 Lappeenranta, Finland.
| | - Antti Häkkinen
- Laboratory of Separation Technology, LUT Chemistry, Lappeenranta University of Technology, P.O. Box 20, FI-53851 Lappeenranta, Finland
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Ghorbanian M, Russ DC, Berson RE. Mixing analysis of PCS slurries in a horizontal scraped surface bioreactor. Bioprocess Biosyst Eng 2014; 37:2113-9. [DOI: 10.1007/s00449-014-1189-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 04/06/2014] [Indexed: 11/28/2022]
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Tozzi EJ, McCarthy MJ, Lavenson DM, Cardona M, Powell ARL, Karuna N, Jeoh T. Effect of fiber structure on yield stress during enzymatic conversion of cellulose. AIChE J 2014. [DOI: 10.1002/aic.14374] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Emilio J. Tozzi
- Dept. of Food Science and Technology; University of California, Davis; Davis CA 95616
| | - Michael J. McCarthy
- Dept. of Food Science and Technology; University of California, Davis; Davis CA 95616
| | - David M. Lavenson
- Dept. of Chemical Engineering and Materials Science; University of California, Davis; Davis CA 95616
| | - Maria Cardona
- Dept. of Chemical Engineering and Materials Science; University of California, Davis; Davis CA 95616
| | - and Robert L. Powell
- Dept. of Chemical Engineering and Materials Science; University of California, Davis; Davis CA 95616
| | - Nardrapee Karuna
- Dept. of Biological and Agricultural Engineering; University of California, Davis; Davis CA 95616
| | - Tina Jeoh
- Dept. of Biological and Agricultural Engineering; University of California, Davis; Davis CA 95616
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24
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Samaniuk JR, Shay TW, Root TW, Klingenberg DJ, Scott CT. A novel rheometer design for yield stress fluids. AIChE J 2014. [DOI: 10.1002/aic.14329] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Joseph R. Samaniuk
- Dept. of Chemical and Biological Engineering; University of Wisconsin-Madison; Madison WI 53706
| | - Timothy W. Shay
- Dept. of Chemical and Biological Engineering; University of Wisconsin-Madison; Madison WI 53706
| | - Thatcher W. Root
- Dept. of Chemical and Biological Engineering; University of Wisconsin-Madison; Madison WI 53706
| | - Daniel J. Klingenberg
- Dept. of Chemical and Biological Engineering; University of Wisconsin-Madison; Madison WI 53706
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Kadić A, Palmqvist B, Lidén G. Effects of agitation on particle-size distribution and enzymatic hydrolysis of pretreated spruce and giant reed. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:77. [PMID: 24920958 PMCID: PMC4035727 DOI: 10.1186/1754-6834-7-77] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Accepted: 04/25/2014] [Indexed: 05/13/2023]
Abstract
BACKGROUND Mixing is an energy demanding process which has been previously shown to affect enzymatic hydrolysis. Concentrated biomass slurries are associated with high and non-Newtonian viscosities and mixing in these systems is a complex task. Poor mixing can lead to mass and/or heat transfer problems as well as inhomogeneous enzyme distribution, both of which can cause possible yield reduction. Furthermore the stirring energy dissipation may impact the particle size which in turn may affect the enzymatic hydrolysis. The objective of the current work was to specifically quantify the effects of mixing on particle-size distribution (PSD) and relate this to changes in the enzymatic hydrolysis. Two rather different materials were investigated, namely pretreated Norway spruce and giant reed. RESULTS Changes in glucan hydrolysis and PSD were measured as a function of agitation during enzymatic hydrolysis at fiber loadings of 7 or 13% water-insoluble solids (WIS). Enzymatic conversion of pretreated spruce was strongly affected by agitation rates at the higher WIS content. However, at low WIS content the agitation had almost no effect on hydrolysis. There was some effect of agitation on the hydrolysis of giant reed at high WIS loading, but it was smaller than that for spruce, and there was no measurable effect at low WIS loading. In the case of spruce, intense agitation clearly affected the PSD and resulted in a reduced mean particle size, whereas for giant reed the decrease in particle size was mainly driven by enzymatic action. However, the rate of enzymatic hydrolysis was not increased after size reduction by agitation. CONCLUSIONS The impact of agitation on the enzymatic hydrolysis clearly depends not only on feedstock but also on the solids loading. Agitation was found to affect the PSD differently for the examined pretreated materials spruce and giant reed. The fact that the reduced mean particle diameter could not explain the enhanced hydrolysis rates found for spruce at an elevated agitation suggests that mass transfer at sustained high viscosities plays an important role in determining the rate of enzymatic hydrolysis.
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Affiliation(s)
- Adnan Kadić
- Department of Chemical Engineering, Lund University, Box 124, SE-221 00 Lund, Sweden
| | - Benny Palmqvist
- Department of Chemical Engineering, Lund University, Box 124, SE-221 00 Lund, Sweden
| | - Gunnar Lidén
- Department of Chemical Engineering, Lund University, Box 124, SE-221 00 Lund, Sweden
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Hammed AM, Jaswir I, Amid A, Alam Z, Asiyanbi-H TT, Ramli N. Enzymatic Hydrolysis of Plants and Algae for Extraction of Bioactive Compounds. FOOD REVIEWS INTERNATIONAL 2013. [DOI: 10.1080/87559129.2013.818012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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27
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Nguyen TC, Anne-Archard D, Coma V, Cameleyre X, Lombard E, Binet C, Nouhen A, To KA, Fillaudeau L. In situ rheometry of concentrated cellulose fibre suspensions and relationships with enzymatic hydrolysis. BIORESOURCE TECHNOLOGY 2013; 133:563-572. [PMID: 23466624 DOI: 10.1016/j.biortech.2013.01.110] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 01/18/2013] [Accepted: 01/19/2013] [Indexed: 06/01/2023]
Abstract
This work combines physical and biochemical analyses to scrutinize liquefaction and saccharification of complex lignocellulose materials. A multilevel analysis (macroscopic: rheology, microscopic: particle size and morphology and molecular: sugar product) was conducted at the lab-scale with three matrices: microcrystalline cellulose (MCC), Whatman paper (WP) and extruded paper-pulp (PP). A methodology to determine on-line viscosity is proposed and validated using the concept of Metzner and Otto (1957) and Rieger and Novak's (1973). The substrate suspensions exhibited a shear-thinning behaviour with respect to the power law. A structured rheological model was established to account for the suspension viscosity as a function of shear rate and substrate concentration. The critical volume fractions indicate the transition between diluted, semi-diluted and concentrated regimes. The enzymatic hydrolysis was performed with various solid contents: MCC 273.6 gdm/L, WP 56.0 gdm/L, PP 35.1 gdm/L. During hydrolysis, the suspension viscosity decreased rapidly. The fibre diameter decreased two fold within 2 h of starting hydrolysis whereas limited bioconversion was obtained (10-15%).
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Affiliation(s)
- Tien-Cuong Nguyen
- Laboratoire d'Ingénierie des Systèmes Biologiques et des Procédés (Université de Toulouse, INSA, INRA UMR792, CNRS UMR5504), Toulouse, France.
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Su X, Zhang J, Mackie RI, Cann IKO. Supplementing with non-glycoside hydrolase proteins enhances enzymatic deconstruction of plant biomass. PLoS One 2012; 7:e43828. [PMID: 22952777 PMCID: PMC3428283 DOI: 10.1371/journal.pone.0043828] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Accepted: 07/30/2012] [Indexed: 11/19/2022] Open
Abstract
The glycoside hydrolases (GH) of Caldicellulosiruptor bescii are thermophilic enzymes, and therefore they can hydrolyze plant cell wall polysaccharides at high temperatures. Analyses of two C. bescii glycoside hydrolases, CbCelA-TM1 and CbXyn10A with cellulase and endoxylanase activity, respectively, demonstrated that each enzyme is highly thermostable under static incubation at 70°C. Both enzymes, however, rapidly lost their enzymatic activities when incubated at 70°C with end-over-end shaking. Since crowding conditions, even at low protein concentrations, seem to influence enzymatic properties, three non-glycoside hydrolase proteins were tested for their capacity to stabilize the thermophilic proteins at high temperatures. The three proteins investigated were a small heat shock protein CbHsp18 from C. bescii, a histone MkHistone1 from Methanopyrus kandleri, and bovine RNase A, from a commercial source. Fascinatingly, each of these proteins increased the thermostability of the glycoside hydrolases at 70°C during end-over-end shaking incubation, and this property translated into increases in hydrolysis of several substrates including the bioenergy feedstock Miscanthus. Furthermore, MkHistone1 and RNase A also altered the initial products released from the cello-oligosaccharide cellopentaose during hydrolysis with the cellodextrinase CbCdx1A, which further demonstrated the capacity of the three non-GH proteins to influence hydrolysis of substrates by the thermophilic glycoside hydrolases. The non-GH proteins used in the present report were small proteins derived from each of the three lineages of life, and therefore expand the space from which different polypeptides can be tested for their influence on plant cell wall hydrolysis, a critical step in the emerging biofuel industry.
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Affiliation(s)
- Xiaoyun Su
- Energy Biosciences Institute, University of Illinois, Urbana, Illinois, United States of America
- Institute for Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
| | - Jing Zhang
- Energy Biosciences Institute, University of Illinois, Urbana, Illinois, United States of America
- Institute for Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, United States of America
| | - Roderick I. Mackie
- Energy Biosciences Institute, University of Illinois, Urbana, Illinois, United States of America
- Institute for Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, United States of America
| | - Isaac K. O. Cann
- Energy Biosciences Institute, University of Illinois, Urbana, Illinois, United States of America
- Institute for Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Animal Sciences, University of Illinois, Urbana, Illinois, United States of America
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
- * E-mail:
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Palmqvist B, Lidén G. Torque measurements reveal large process differences between materials during high solid enzymatic hydrolysis of pretreated lignocellulose. BIOTECHNOLOGY FOR BIOFUELS 2012; 5:57. [PMID: 22867035 PMCID: PMC3502536 DOI: 10.1186/1754-6834-5-57] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Accepted: 07/30/2012] [Indexed: 05/03/2023]
Abstract
BACKGROUND A common trend in the research on 2nd generation bioethanol is the focus on intensifying the process and increasing the concentration of water insoluble solids (WIS) throughout the process. However, increasing the WIS content is not without problems. For example, the viscosity of pretreated lignocellulosic materials is known to increase drastically with increasing WIS content. Further, at elevated viscosities, problems arise related to poor mixing of the material, such as poor distribution of the enzymes and/or difficulties with temperature and pH control, which results in possible yield reduction. Achieving good mixing is unfortunately not without cost, since the power requirements needed to operate the impeller at high viscosities can be substantial. This highly important scale-up problem can easily be overlooked. RESULTS In this work, we monitor the impeller torque (and hence power input) in a stirred tank reactor throughout high solid enzymatic hydrolysis (< 20% WIS) of steam-pretreated Arundo donax and spruce. Two different process modes were evaluated, where either the impeller speed or the impeller power input was kept constant. Results from hydrolysis experiments at a fixed impeller speed of 10 rpm show that a very rapid decrease in impeller torque is experienced during hydrolysis of pretreated arundo (i.e. it loses its fiber network strength), whereas the fiber strength is retained for a longer time within the spruce material. This translates into a relatively low, rather WIS independent, energy input for arundo whereas the stirring power demand for spruce is substantially larger and quite WIS dependent. By operating the impeller at a constant power input (instead of a constant impeller speed) it is shown that power input greatly affects the glucose yield of pretreated spruce whereas the hydrolysis of arundo seems unaffected. CONCLUSIONS The results clearly highlight the large differences between the arundo and spruce materials, both in terms of needed energy input, and glucose yields. The impact of power input on glucose yield is furthermore shown to vary significantly between the materials, with spruce being very affected while arundo is not. These findings emphasize the need for substrate specific process solutions, where a short pre-hydrolysis (or viscosity reduction) might be favorable for arundo whereas fed-batch might be a better solution for spruce.
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Affiliation(s)
- Benny Palmqvist
- Department of Chemical Engineering, Lund University, Box 124, Lund, SE-221 00, Sweden
| | - Gunnar Lidén
- Department of Chemical Engineering, Lund University, Box 124, Lund, SE-221 00, Sweden
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Kinnarinen T, Shakhanova M, Hietanen E, Salmimies R, Häkkinen A, Louhi-Kultanen M. Effect of mixing on enzymatic hydrolysis of cardboard waste: saccharification yield and subsequent separation of the solid residue using a pressure filter. BIORESOURCE TECHNOLOGY 2012; 110:405-411. [PMID: 22357287 DOI: 10.1016/j.biortech.2012.01.138] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 01/16/2012] [Accepted: 01/20/2012] [Indexed: 05/31/2023]
Abstract
Cellulosic wastes, from sources such as low-quality cardboard and paper, are regarded as potential feedstocks for bioethanol production. One pathway from these cellulosic materials to ethanol is saccharification (hydrolysis) followed by fermentation. Saccharification is commonly performed using enzymes that are able to cleave the cellulosic structure to smaller units, preferably to glucose monomers. During the hydrolysis, mixing conditions have a considerable impact on the performance of the enzymes. Thus mixing conditions in the hydrolysis tank can also influence the downstream operations and, consequently, the overall economy of the bioethanol process. In this experimental study, four types of impeller, at different hydrolysis conditions were used. The effect of mixing on the glucose yield and on the filtration characteristics of the hydrolysate was evaluated. It was shown that not only the sugar yield depended on the mixing conditions: the effect on the solid-liquid separation step was even more significant.
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Affiliation(s)
- Teemu Kinnarinen
- LUT Chemistry, Lappeenranta University of Technology, P.O. Box 20, FIN-53851 Lappeenranta, Finland.
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Van Dyk JS, Pletschke BI. A review of lignocellulose bioconversion using enzymatic hydrolysis and synergistic cooperation between enzymes--factors affecting enzymes, conversion and synergy. Biotechnol Adv 2012; 30:1458-80. [PMID: 22445788 DOI: 10.1016/j.biotechadv.2012.03.002] [Citation(s) in RCA: 476] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 02/10/2012] [Accepted: 03/06/2012] [Indexed: 02/04/2023]
Abstract
Lignocellulose is a complex substrate which requires a variety of enzymes, acting in synergy, for its complete hydrolysis. These synergistic interactions between different enzymes have been investigated in order to design optimal combinations and ratios of enzymes for different lignocellulosic substrates that have been subjected to different pretreatments. This review examines the enzymes required to degrade various components of lignocellulose and the impact of pretreatments on the lignocellulose components and the enzymes required for degradation. Many factors affect the enzymes and the optimisation of the hydrolysis process, such as enzyme ratios, substrate loadings, enzyme loadings, inhibitors, adsorption and surfactants. Consideration is also given to the calculation of degrees of synergy and yield. A model is further proposed for the optimisation of enzyme combinations based on a selection of individual or commercial enzyme mixtures. The main area for further study is the effect of and interaction between different hemicellulases on complex substrates.
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Affiliation(s)
- J S Van Dyk
- Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, PO Box 94, Grahamstown, 6140, South Africa
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32
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Ye Z, Hatfield KM, Berson RE. Deactivation of individual cellulase components. BIORESOURCE TECHNOLOGY 2012; 106:133-137. [PMID: 22200557 DOI: 10.1016/j.biortech.2011.11.134] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 11/29/2011] [Accepted: 11/30/2011] [Indexed: 05/31/2023]
Abstract
Deactivation extents of cellobiohydrolase, endoglucanase, and a total cellulase mixture (Spezyme CP) were studied independently as functions of incubating time and mixing intensity. It was found that the decrease in total cellulase activity was more strongly related to deactivation of cellobiohydrolase 1 (CBH1) than endoglucanase. The mass-averaged shear in orbiting flasks at 50, 150, and 250rpm was quantified by computational fluid dynamics and was two-orders smaller than shear in typical stirred tanks. Endoglucanase activity did not change significantly with mixing speed, but CBH1 and total cellulase activities were 10-25% higher at 250rpm compared to the lower speeds after a 24-h incubation. Total deactivation due to mechanical mixing (∼20%) may be too low to account for all the rate reduction during cellulose hydrolysis. Thermal deactivation was independent of enzyme concentration while deactivation due to mechanical stress decreased when cellulase loading increased over 0.15 filterpaperunit/ml.
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Affiliation(s)
- Zhuoliang Ye
- Department of Chemical Engineering, University of Louisville, Louisville, KY 40292, USA
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33
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Riedlberger P, Weuster-Botz D. New miniature stirred-tank bioreactors for parallel study of enzymatic biomass hydrolysis. BIORESOURCE TECHNOLOGY 2012; 106:138-146. [PMID: 22206921 DOI: 10.1016/j.biortech.2011.12.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 12/02/2011] [Accepted: 12/03/2011] [Indexed: 05/31/2023]
Abstract
Many factors strongly influence the enzymatic hydrolysis of biomass to fermentable sugars (feedstock composition, pretreatment, enzymes and enzyme loading). In order to optimize the reaction conditions for the hydrolysis of biomass, an accurate high-throughput bioprocess development tool is mandatory, which enables a parallelization and an easy scale-up. New S-shaped impellers were developed for magnetically inductive driven stirred-tank bioreactors at a 10mL-scale. An efficient and reproducible homogenization was shown at 20% w/w solids loading of microcrystalline cellulose and at, 4-10% with wheat straw in 48 parallel operated stirred-tank bioreactors. The scale-up was successfully validated for the enzymatic hydrolysis of wheat straw suspensions and microcrystalline cellulose mixtures by application of a cellulase complex at a milliliter- and liter-scale. As an example, the parallel stirred-tank bioreactor system was applied for the evaluation of enzymatic batch hydrolyses of plant materials with varying pretreatments.
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Affiliation(s)
- Peter Riedlberger
- Lehrstuhl für Bioverfahrenstechnik, Technische Universität München, Boltzmannstr. 15, 85748 Garching, Germany
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34
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Zhu JY, Gleisner R, Scott CT, Luo XL, Tian S. High titer ethanol production from simultaneous enzymatic saccharification and fermentation of aspen at high solids: a comparison between SPORL and dilute acid pretreatments. BIORESOURCE TECHNOLOGY 2011; 102:8921-9. [PMID: 21824766 DOI: 10.1016/j.biortech.2011.07.047] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 07/06/2011] [Accepted: 07/15/2011] [Indexed: 05/18/2023]
Abstract
Native aspen (Populus tremuloides) was pretreated using sulfuric acid and sodium bisulfite (SPORL) and dilute sulfuric acid alone (DA). Simultaneous enzymatic saccharification and fermentation (SSF) was conducted at 18% solids using commercial enzymes with cellulase loadings ranging from 6 to 15 FPU/g glucan and Saccharomyces cerevisiae Y5. Compared with DA pretreatment, the SPORL pretreatment reduced the energy required for wood chip size-reduction, and reduced mixing energy of the resultant substrate for solid liquefaction. Approximately 60% more ethanol was produced from the solid SPORL substrate (211 L/ton wood at 59 g/L with SSF efficiency of 76%) than from the solid DA substrate (133 L/ton wood at 35 g/L with SSF efficiency 47%) at a cellulase loading of 10 FPU/g glucan after 120 h. When the cellulase loading was increased to 15 FPU/g glucan on the DA substrate, the ethanol yield still remained lower than the SPORL substrate at 10 FPU/g glucan.
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Affiliation(s)
- J Y Zhu
- USDA Forest Service, Forest Products Laboratory, Madison, WI, USA.
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35
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Lavenson DM, Tozzi EJ, McCarthy MJ, Powell RL. Yield stress of pretreated corn stover suspensions using magnetic resonance imaging. Biotechnol Bioeng 2011; 108:2312-9. [DOI: 10.1002/bit.23197] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 04/12/2011] [Accepted: 04/25/2011] [Indexed: 11/05/2022]
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