Improving Fermentation of Pretreated Biomass by Reducing Inhibitor Concentrations and Increasing Microbial Biocatalyst Tolerance PDF Download
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Author: Ryan Geddes
Publisher:
ISBN:
Category :
Languages : en
Pages : 105
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Book Description
Required to complete fermentation. A second process-based approach for improving hydrolysate fermentatbility was employed. Tube culture assays were designed that focus on comparing biological, chemical and physical treatments of hydrolysate. Six strategies were investigated that reduced toxicity in hemicellulose hydrolysates of sugarcane bagasse. These strategies included the use of vacuum evaporation, laccase enzymes, high pH treatment (ammonium hydroxide), bisulfite and increasing cell mass either by increased inoculum or by providing a low level of aeration (0.01 vvm). High pH was the most beneficial single treatment, increasing the minimum inhibitory concentration from 15% (control) to 70% hydrolysate. Tube culture assays of toxicity for ethanol production proved to be excellent predictors of performance in pH-controlled fermenters. A combination of treatments completely eliminated all inhibitory activity in hydrolysate, rendering it as fermentable as laboratory mineral salts medium without hydrolysate.
Author: Ryan Geddes
Publisher:
ISBN:
Category :
Languages : en
Pages : 105
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Book Description
Required to complete fermentation. A second process-based approach for improving hydrolysate fermentatbility was employed. Tube culture assays were designed that focus on comparing biological, chemical and physical treatments of hydrolysate. Six strategies were investigated that reduced toxicity in hemicellulose hydrolysates of sugarcane bagasse. These strategies included the use of vacuum evaporation, laccase enzymes, high pH treatment (ammonium hydroxide), bisulfite and increasing cell mass either by increased inoculum or by providing a low level of aeration (0.01 vvm). High pH was the most beneficial single treatment, increasing the minimum inhibitory concentration from 15% (control) to 70% hydrolysate. Tube culture assays of toxicity for ethanol production proved to be excellent predictors of performance in pH-controlled fermenters. A combination of treatments completely eliminated all inhibitory activity in hydrolysate, rendering it as fermentable as laboratory mineral salts medium without hydrolysate.
Author: Zonglin Lewis Liu
Publisher: Springer Science & Business Media
ISBN: 3642214673
Category : Science
Languages : en
Pages : 311
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Book Description
The development of sustainable and renewable biofuels is attracting growing interest. It is vital to develop robust microbial strains for biocatalysts that are able to function under multiple stress conditions. This Microbiology Monograph provides an overview of methods for studying microbial stress tolerance for biofuels applications using a systems biology approach. Topics covered range from mechanisms to methodology for yeast and bacteria, including the genomics of yeast tolerance and detoxification; genetics and regulation of glycogen and trehalose metabolism; programmed cell death; high gravity fermentations; ethanol tolerance; improving biomass sugar utilization by engineered Saccharomyces; the genomics on tolerance of Zymomonas mobilis; microbial solvent tolerance; control of stress tolerance in bacterial host organisms; metabolomics for ethanologenic yeast; automated proteomics work cell systems for strain improvement; and unification of gene expression data for comparable analyses under stress conditions.
Author: Manoj Agrawal
Publisher:
ISBN:
Category : Anaerobic bacteria
Languages : en
Pages :
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Book Description
Ethanol from lignocellulosic biomass is a promising alternative to rapidly depleting oil reserves. However, natural recalcitrance of lignocelluloses to biological and chemical treatments presents major engineering challenges in designing an ethanol conversion process. Current methods for pretreatment and hydrolysis of lignocelluloses generate a mixture of pentose (C5) and hexose (C6) sugars, and several microbial growth inhibitors such as acetic acid and phenolic compounds. Hence, an efficient ethanol production process requires a fermenting microorganism not only capable of converting mixed sugars to ethanol with high yield and productivity, but also having high tolerance to inhibitors. Although recombinant bacteria and yeast strains have been developed, ethanol yield and productivity from C5 sugars in the presence of inhibitors remain low and need to be further improved for a commercial ethanol production. The overarching objective of this work is to transform Zymomonas mobilis into an efficient whole-cell biocatalyst for ethanol production from lignocelluloses. Z. mobilis, a natural ethanologen, is ideal for this application but xylose (a C5 sugar) is not its 'natural' substrate. Back in 1995, researches at National Renewable Energy Laboratory (NREL) had managed to overcome this obstacle by metabolically engineering Z. mobilis to utilize xylose. However, even after more than a decade of research, xylose fermentation by Z. mobilis is still inefficient compared to that of glucose. For example, volumetric productivity of ethanol from xylose fermentation is 3- to 4- fold lower than that from glucose fermentation. Further reduction or complete inhibition of xylose fermentation occurs under adverse conditions. Also, high concentrations of xylose do not get metabolized completely. Thus, improvement in xylose fermentation by Z. mobilis is required. In this work, xylose fermentation in a metabolically engineered Z. mobilis was markedly improved by applying the technique of adaptive mutation. The adapted strain was able to grow on 10% (w/v) xylose and rapidly ferment xylose to ethanol within 2 days and retained high ethanol yield. Similarly, in mixed glucose-xylose fermentation, the strain produced a total of 9% (w/v) ethanol from two doses of 5% glucose and 5% xylose (or a total of 10% glucose and 10% xylose). Investigation was done to identify the molecular basis for efficient biocatalysis. An altered xylitol metabolism with reduced xylitol formation, increased xylitol tolerance and higher xylose isomerase activity were found to contribute towards improvement in xylose fermentation. Lower xylitol production in adapted strain was due to a single mutation in ZMO0976 gene, which drastically lowered the reductase activity of ZMO0976 protein. ZMO0976 was characterized as a novel aldo-keto reductase capable of reducing xylose, xylulose, benzaldehyde, furfural, 5-hydroxymethyl furfural, and acetaldehyde, but not glucose or fructose. It exhibited nearly 150-times higher affinity with benzaldehyde than xylose. Knockout of ZMO0976 was found to facilitate the establishment of xylose fermentation in Z. mobilis ZM4. Equipped with molecular level understanding of the biocatalytic process and insight into Z. mobilis central carbon metabolism, further genetic engineering of Z. mobilis was undertaken to improve the fermentation of sugars and lignocellulosic hydrolysates. These efforts culminated in construction of a strain capable of fermenting glucose-xylose mixture in presence of high concentration of acetic acid and another strain with a partially operational EMP pathway.
Author: Anwar Sunna
Publisher: MDPI
ISBN: 3039434640
Category : Science
Languages : en
Pages : 332
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Book Description
The concept of a circular economy relies on waste reduction, valorization, and recycling. Global trends for “green” synthesis of chemicals have positioned the field of enzyme technology and biocatalysis (multi-enzymes and whole-cells) as an alternative for the synthesis of more social- and environmentally-responsible bio-based chemicals. Recent advances in synthetic biology, computational tools, and metabolic engineering have supported the discovery of new enzymes and the rational design of whole-cell biocatalysts. In this book, we highlight these current advances in the field of biocatalysis, with special emphasis on novel enzymes and whole-cell biocatalysts for applications in several industrial biotechnological applications.
Author: Michele Aresta
Publisher: Walter de Gruyter GmbH & Co KG
ISBN: 3110331586
Category : Science
Languages : en
Pages : 368
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Book Description
Biorefineries compiles the basic science and technologies used to convert terrestrial and aquatic biomass into essential molecular compounds and polymeric materials. The book provides in depth insights into this fairly recent concept of industrial chemistry that aims to achieve optimal economic profits while minimizing the environmental impact. Chapters written by renowned experts cover, amongst others, the application of catalysis, downstream processing, biomass sourced olefins, lignin biorefinery techniques and biogas. The authors thoroughly examine and explain the value chain for biomass conversion into platform molecules and their transformation into final products. A comprehensive thematic overview on the topic giving beginners access to fundamental concepts is presented. Supplemented by numerous full color figures and tables, the contents impart knowledge about the involved techniques. Advanced students and experts in the field will find the summary of state-of-the-art research and current literature of valuable interest. Explores the enormous potential of biomass conversion as a future source for fuels and chemicals Focuses on both general scientific background and current innovations in the field of biorefinery Targets students and researchers in Chemistry, Chemical Engineering, Biotechnology, and Materials Science About the Editors Prof. Michele Aresta, Chair of the Scientific Committee of CIRCC in Italy and holds the IMM Chair at the Department of Chemical and Biomolecular Engineering at NUS, Singapore. He is author of over 200 papers and Author or Editor of nine books. Prof. Angela Dibenedetto, Associate Professor at the Department of Chemistry of the University of Bari (Italy) focused on carbon dioxide utilization by applying biorefinery concepts; and Director of the Interuniversity Consortium on Chemical Reactivity and Catalysis-CIRCC. Prof. Franck Dumeignil, Deputy Director of the CNRS joint Unit of Catalysis and Chemistry of Solid (UCCS) of Lille University (France); project coordinator of several projects on chemistry, including the EuroBioRef Project for designing next generation biorefineries.
Author: Hongzhang Chen
Publisher: Academic Press
ISBN: 0128025948
Category : Technology & Engineering
Languages : en
Pages : 292
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Book Description
Technologies for Biochemical Conversion of Biomass introduces biomass biochemical conversion technology, including the pretreatment platform, enzyme platform, cell refining platform, sugar platform, fermentation platform, and post-treatment platform. Readers will find a systematic treatment, not only of the basics of biomass biochemical conversion and the introduction of each strategy, but also of the current advances of research in this area. Researchers will find the key problems in each technology platform for biomass biochemical conversion identified and solutions offered. This valuable reference book features new scientific research and the related industrial application of biomass biochemical conversion technology as the main content, and then systematically introduces the basic principles and applications of biomass biochemical conversion technology. - Combines descriptions of these technologies to provide strategies and a platform for biochemical conversion in terms of basic knowledge, research advances, and key problems - Summarizes models of biomass biochemical conversion for multiple products - Presents products of biomass biochemical conversion from C1 to C10
Author: Thaddeus Ezeji
Publisher: MDPI
ISBN: 3038425540
Category : Science
Languages : en
Pages : 197
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Book Description
This book is a printed edition of the Special Issue "Biofuels and Biochemicals Production" that was published in Fermentation
Author: Anuj Chandel
Publisher: BoD – Books on Demand
ISBN: 9535111191
Category : Technology & Engineering
Languages : en
Pages : 288
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Book Description
This book provides important aspects of sustainable degradation of lignocellulosic biomass which has a pivotal role for the economic production of several value-added products and biofuels with safe environment. Different pretreatment techniques and enzymatic hydrolysis process along with the characterization of cell wall components have been discussed broadly. The following features of this book attribute its distinctiveness: This book comprehensively covers the improvement in methodologies for the biomass pretreatment, hemicellulose and cellulose breakdown into fermentable sugars, the analytical methods for biomass characterization, and bioconversion of cellulosics into biofuels. In addition, mechanistic analysis of biomass pretreatment and enzymatic hydrolysis have been discussed in details, highlighting key factors influencing these processes at industrial scale.
Author: Jitendra Kumar Saini
Publisher: Springer Nature
ISBN: 9811638527
Category : Science
Languages : en
Pages : 403
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Book Description
This book covers various aspects of microbial biotechnology to produce bioenergy. It focuses on production of biofuels from plant and microbial biomass including agri-food residues and other wastes. It educates readers about various biomass resources, major aspects of production of renewable energy and fuels based on biochemical conversion routes. There is special focus on the microbial system and biotechnological processes as well as process optimization and industrial scale-up. The book brings together current challenges and potential solutions to enhance biomass to biofuel bioconversion. It is relevant for researchers, academicians, students as well as industry professionals working on biomass-based biorefineries.
Author: Eero Sjöström
Publisher: Springer Science & Business Media
ISBN: 3662038986
Category : Science
Languages : en
Pages : 344
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Book Description
In its broadest sense, and according to the traditional conception, wood chemistry is a comprehensive discipline, ranging from fundamental studies to practical applications. The manifold constituents, located in different morphological regions in the wood, results in an extreme complexity of wood chemistry. Ever more sophisticated endeavors needing fundamental studies and advanced analytical methods are necessary in order to delve deeper into various problems in pulping and papermaking. Gradually, new, improved ana lytical methods, originally developed for research purposes, are currently replacing many of the old "routine" methods in practical applications. Because of the expanse of the subject, an attempt to write a book of this size about analytical methods seems, perhaps, too ambitious. Of course, a whole book series of several volumes would be necessary to cover this topic completely. However, there is undoubtedly a need for a more condensed presentation which does not go into experimental details, but is limited to the basic principles of the analytical methods and illustrates their applica tions. The emphasis is on more advanced and potential methods, and partic ularly on those based on different types of spectroscopy and chromatography.
