Metabolic Engineering of Cellulolytic Clostridium Cellulovorans for Biofuel Production Directly from Cellulosic Biomass PDF Download
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Author: Xiaorui Yang
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
In summary, C. cellulovorans was metabolically engineered to produce n-butanol and ethanol directly from cellulosic biomass, with the development of its transformation method for the first time. In addition, the engineered C. cellulovorans could produce 1.6 g/L n-butanol directly from cellulose, which is the highest, compared to other wild-type and engineered cellulolytic strains. This project provided a promising platform for the production of biofuel and other value-added products directly from lignocellulosic biomass.
Author: Xiaorui Yang
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
In summary, C. cellulovorans was metabolically engineered to produce n-butanol and ethanol directly from cellulosic biomass, with the development of its transformation method for the first time. In addition, the engineered C. cellulovorans could produce 1.6 g/L n-butanol directly from cellulose, which is the highest, compared to other wild-type and engineered cellulolytic strains. This project provided a promising platform for the production of biofuel and other value-added products directly from lignocellulosic biomass.
Author: Teng Bao
Publisher:
ISBN:
Category : Biochemical engineering
Languages : en
Pages : 205
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Book Description
Clostridium cellulovorans is a strictly anaerobic, cellulolytic bacterium among the most interesting candidates for CBP of lignocellulosic biomass. Recently, a bifunctional aldehyde/alcohol dehydrogenase gene adhE2 from Clostridium acetobutylicum has been overexpressed in C. cellulovorans for n-butanol production from cellulose. However, this recombinant strain produced n-butanol from microcrystalline cellulose at a low titer and yield insufficient for industrial application. In addition, there are two type II restriction modification (RM) systems in C. cellulovorans and currently available plasmids would be digested by C. cellulovorans cell extract even after in vivo methylation, making it difficult to transfer and express genes in C. cellulovorans for further metabolic engineering. Therefore, efficient transformation for developing better recombinant C. cellulovorans for butanol production is urgently required.
Author: Beth Alexandra Papanek
Publisher:
ISBN:
Category : Biomass energy
Languages : en
Pages : 91
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Book Description
Biofules are an important option for humanity to move away from its dependence on fossil fuels. Transitioning from food crops to lignocellulosic alternatives for the production of biofuels is equally important. Most commonly, biofuels are produced using a crop such as corn or soybeans to feed sugars to the yeast, Saccharomyces cerevisiae for the fermentation of ethanol. Lignocellulosic biofuel production would eliminate the need for food crops and transition to biomass such as switchgrass, poplar, or corn stover. Currently, lignocellulosic biofuel production is limited primarily because of the cost of converting the biomass to fermentable sugars than can then be metabolized by yeast. To overcome this barrier, a process must be employed that can convert lignocellulosic biomass directly to fuels and chemicals quickly and affordably. Clostridium thermocellum is one of the most promising candidates for the production of advanced biofuels because of its potential ability to convert cellulose directly to ethanol without the expensive addition of enzymes. Challenges to implementing C. thermocellum on an industrial scale still exist including side product formation, slow growth, limited titers, inhibition on high solids loadings, and a limited ability to perform genetic engineering. This thesis considers all of these concerns with C. thermocellum and attempts to systematically improve each characteristic to produce an industrially relevant strain of C. thermocellum for advanced biofuel production. Metabolic engineering is applied for the elimination of undesirable fermentation products. Laboratory evolution and medium supplementation are used to improve and understand the mechanisms that influence growth rate, and systematic approaches are used to improve transformation for more efficient genetic engineering of C. thermocellum in the future.
Author: Arindam Kuila
Publisher: Elsevier
ISBN: 0128179546
Category : Technology & Engineering
Languages : en
Pages : 256
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Book Description
Genetic and Metabolic Engineering for Improved Biofuel Production from Lignocellulosic Biomass describes the different aspects of biofuel production from lignocellulosic biomass. Each chapter presents different technological approaches for cost effective liquid biofuel production from agroresidues/biomass. Two chapters cover future direction and the possibilities of biomass-based biofuel production at the industrial level. The book provides a genetic and metabolic engineering approach for improved cellulase production and the potential of strains that can ferment both pentose and hexose sugars. The book also gives direction on how to overcome challenges for the further advancement of lignocellulosic biomass-based biofuel production. - Covers genetic engineering approaches for higher cellulase production from fungi - Includes genetic and metabolic engineering approaches for development of potential pentose and hexose fermenting strain which can tolerate high ethanol and toxic phenolic compounds - Describe different bioreactors used in different steps of biomass-based biofuel production - Outlines future prospects and potential of biofuel production from lignocellulosic biomass
Author: Vincenza Faraco
Publisher: Springer Science & Business Media
ISBN: 3642378617
Category : Science
Languages : en
Pages : 207
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Book Description
Bioethanol has been recognized as a potential alternative to petroleum-derived transportation fuels. Even if cellulosic biomass is less expensive than corn and sugarcane, the higher costs for its conversion make the near-term price of cellulosic ethanol higher than that of corn ethanol and even more than that of sugarcane ethanol. Conventional process for bioethanol production from lignocellulose includes a chemical/physical pre-treatment of lignocellulose for lignin removal, mostly based on auto hydrolysis and acid hydrolysis, followed by saccharification of the free accessible cellulose portions of the biomass. The highest yields of fermentable sugars from cellulose portion are achieved by means of enzymatic hydrolysis, currently carried out using a mix of cellulases from the fungus Trichoderma reesei. Reduction of (hemi)cellulases production costs is strongly required to increase competitiveness of second generation bioethanol production. The final step is the fermentation of sugars obtained from saccharification, typically performed by the yeast Saccharomyces cerevisiae. The current process is optimized for 6-carbon sugars fermentation, since most of yeasts cannot ferment 5-carbon sugars. Thus, research is aimed at exploring new engineered yeasts abilities to co-ferment 5- and 6-carbon sugars. Among the main routes to advance cellulosic ethanol, consolidate bio-processing, namely direct conversion of biomass into ethanol by a genetically modified microbes, holds tremendous potential to reduce ethanol production costs. Finally, the use of all the components of lignocellulose to produce a large spectra of biobased products is another challenge for further improving competitiveness of second generation bioethanol production, developing a biorefinery.
Author: Christopher Mark Gowen
Publisher:
ISBN:
Category : Biomass energy
Languages : en
Pages :
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Book Description
Metabolic engineering of microorganisms for chemical production involves the coordination of regulatory, kinetic, and thermodynamic parameters within the context of the entire network, as well as the careful allocation of energetic and structural resources such as ATP, redox potential, and amino acids. The exponential progression of "omics" technologies over the past few decades has transformed our ability to understand these network interactions by generating enormous amounts of data about cell behavior. The great challenge of the new biological era is in processing, integrating, and rationally interpreting all of this information, leading to testable hypotheses. In silico metabolic reconstructions are versatile computational tools for integrating multiple levels of bioinformatics data, facilitating interpretation of that data, and making functional predictions related to the metabolic behavior of the cell. To explore the use of this modeling paradigm as a tool for enabling metabolic engineering in a poorly understood microorganism, an in silico constraint-based metabolic reconstruction for the anaerobic, cellulolytic bacterium Clostridium thermocellum was constructed based on available genome annotations, published phenotypic information, and specific biochemical assays. This dissertation describes the analysis and experimental validation of this model, the integration of transcriptomic data from an RNAseq experiment, and the use of the resulting model for generating novel strain designs for significantly improved production of ethanol from cellulosic biomass. The genome-scale metabolic reconstruction is shown to be a powerful framework for understanding and predicting various metabolic phenotypes, and contributions described here enhance the utility of these models for interpretation of experimental datasets for successful metabolic engineering.
Author: John Kadla
Publisher: BoD – Books on Demand
ISBN: 9535111728
Category : Science
Languages : en
Pages : 238
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Book Description
Cellulose is only one of the components of biomass, although being the most abundant. To make useful chemicals or materials from cellulose requires as the first step the separation of cellulose from biomass. Various issues of cellulose extraction and its conversion are discussed in the chapters of this book on cellulose, the third and last one of a series of books on cellulose. This conversion of cellulose is an integral part of the biorefinery concept, an effort to derive optimum value from all biomass components, and as such compulsory reading for students and researchers in this area.
Author: Michael Pyne
Publisher:
ISBN:
Category :
Languages : en
Pages : 154
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Book Description
Reducing the production cost of industrial biofuels will greatly facilitate their proliferation and co-integration with fossil fuels. The cost of feedstock is the largest cost in most fermentation bioprocesses and therefore represents an important target for cost reduction. Meanwhile, the biorefinery concept advocates revenue growth through complete utilization of by-products generated during biofuel production. Taken together, the production of biofuels from low-cost crude glycerol, available in oversupply as a by-product of bioethanol production, in the form of thin stillage, and biodiesel production, embodies a remarkable opportunity to advance affordable biofuel development. However, few bacterial species possess the natural capacity to convert glycerol as a sole source of carbon and energy into value-added bioproducts. Of particular interest is the anaerobe Clostridium pasteurianum, the only microorganism known to convert glycerol alone directly into butanol, which currently holds immense promise as a high-energy biofuel and bulk chemical. Unfortunately, genetic and metabolic engineering of C. pasteurianum has been fundamentally impeded due to a complete lack of genetic tools and techniques available for the manipulation of this promising bacterium. This thesis encompasses the development of fundamental genetic tools and techniques that will permit extensive genetic and metabolic engineering of C. pasteurianum.
Author: Robert Carlo Carere
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Book Description
Consolidated bioprocessing, a process in which cellulase production, substrate hydrolysis, and fermentation occur simultaneously, offers the potential for lower biofuel production costs than traditional approaches and is an economically attractive near-term goal for fermentative production of ethanol and/or hydrogen (H2) as biofuels. Current yields fall short of theoretical maxima, vary considerably between species, and are influenced by the highly branched metabolic pathways utilized by fermentative organisms. For fermentative ethanol/ H2 production to become practical, yields must be increased either through intelligent species selection, a manipulation of culture conditions, or via the implementation of rational metabolic engineering strategies. A comparative genomics approach amoungst select members of the Firmicutes, Euryarchaeota, and Thermotogae was used to identify genes relevent to ethanol and H2 production. Growth, end-product synthesis, enzyme activities and the associated transcription of select genes were studied in the cellulolytic anaerobe, Clostridium thermocellum ATCC 27405, during batch fermentation of cellobiose to determine the effect of elevated N2 and H2 sparging on end-product distribution. The absence of genes encoding acetaldehyde dehydrogenase and bifunctional acetaldehyde/alcohol dehydrogenase (AdhE) correlates with elevated H2 yields and low ethanol production. The type(s) of encoded hydrogenases appear to have minimal impact on H2 production in organisms that do not encode ethanologenic pathways, however, they do influence reduced end-product yields in those that do. We also find that while gas sparging can be used to effectively shift carbon and electron flow, the observed shifts at the pyruvate branch-point are likely principally influenced by the availability of reduced electron carriers (NAD, NADP, ferredoxin) and thermodynamic considerations. Finally, both electrotransformation and conjugative plasmid protocols were developed and evaluated for thermophilic species C. thermocellum and Thermoanaerobacter pseudethanolicus 39E, and the mesophilic bacterium, Clostridium termitidis CT1112. The efficiency of transformation for C. thermocellum strain ATCC 27405 is consistently low whereas transformation frequencies were ~100-fold higher in C. termitidis. Observed frequencies of plasmid transfer, via conjugation, were similar in both C. thermocellum and C. termitidis suggesting the transfer of single stranded DNA may circumvent aggressive restriction methylation systems.
Author: Yi-Tong Wang
Publisher: MDPI
ISBN: 3039363123
Category : Technology & Engineering
Languages : en
Pages : 208
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Book Description
Biomass is the only renewable carbon source that can be converted into high value-added carbon products. This book presents a collection of studies on the conversion of catalytic biomass to renewable biofuels and biomaterials by chemical conversion, co-combustion technology, and biological conversion technology. The fundamentals and mechanisms of catalytic materials design, process optimization, product development, and by-product utilization are outlined. All articles were contributed by experts in catalysis and bioenergy fields to provide readers with a broad range of perspectives on cutting-edge applications. This book is an ideal reference guide for academic researchers and engineering technicians in the fields of catalytic material synthesis, biomass energy conversion, enzyme catalysis, pyrolysis, combustion, vaporization, and fermentation. It can also be used as a comprehensive reference source for university students in renewable energy science and engineering, agricultural engineering, thermal engineering, chemical engineering, material science, and environmental engineering. This book contains 12 articles: (1) “Catalytic Biomass to Renewable Biofuels and Biomaterials”; (2) “Experimental Design to Improve Cell Growth and Ethanol Production in Syngas Fermentation by Clostridium carboxidivorans”; (3) “Glycerol Acetylation Mediated by Thermally Hydrolysed Biosolids-Based Material”; (4) “Influence of Base-Catalyzed Organosolv Fractionation of Larch Wood Sawdust on Fraction Yields and Lignin Properties”; (5) “Ca-based Catalysts for the Production of High-Quality Bio-Oils from the Catalytic Co-Pyrolysis of Grape Seeds and Waste Tyres”; (6) “Synthesis of Diesel and Jet Fuel Range Cycloalkanes with Cyclopentanone and Furfural”; (7) “Gel-Type and Macroporous Cross-Linked Copolymers Functionalized with Acid Groups for the Hydrolysis of Wheat Straw Pretreated with an Ionic Liquid”; (8) “Role of Humic Acid Chemical Structure Derived from Different Biomass Feedstocks on Fe(III) Bioreduction Activity: Implication for Sustainable Use of Bioresources”; (9) “Selective Production of Terephthalonitrile and Benzonitrile via Pyrolysis of Polyethylene Terephthalate (PET) with Ammonia over Ca(OH)2/Al2O3 Catalysts”; (10) “Experimental Studies on Co-Combustion of Sludge and Wheat Straw”; (11) “Carbonate-Catalyzed Room-Temperature Selective Reduction of Biomass-Derived 5-Hydroxymethylfurfural into 2,5-Bis(hydroxymethyl)furan”; (12) “Clostridium sp. as Bio-Catalyst for Fuels and Chemicals Production in a Biorefinery Context”.
