The influence of enzymatic liquefaction and slurry rheology on high-solids cellulose hydrolysis
department or school: Forestry, Faculty of
data provider: DSpace
degree campus: UBCV
creator: van der Zwan, Timo William
issued: 2018-08-10T20:30:48Z
issued: 2018
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Enzyme-mediated hydrolysis of lignocellulosic materials for their conversion into bioproducts would benefit significantly if high solids concentrations (low water-to-biomass ratios) could be processed effectively. However, the fibrous nature of lignocellulosic biomass makes effective reaction mixing difficult, resulting in mass transfer limitations that reduce process yields. Overcoming these rheological challenges will require a better understanding of the substrate properties that influence slurry rheology, and in particular, how the action of carbohydrate-active enzymes can better facilitate slurry viscosity reduction, or ‘enzymatic liquefaction’. To this end, the work described in this thesis assessed: the underlying causes of the rheological challenge of high-solids bioconversion; the possible mechanisms of enzymatic liquefaction; how liquefaction is influenced by the nature of the substrate; and the roles the various enzymes play in liquefaction. It was apparent that the relationship between substrate properties, slurry rheology and high-solids hydrolysis kinetics is complex and multifaceted. Substrate–water interactions were shown to be a key determinant that influenced the mass transfer boundary and the scaling of yield stress with solids loading. The yield stress profiles of the various pretreated substrates varied extensively, indicating that ‘high solids’ is a relative, substrate-dependent quality. Substrate rheological characteristics, especially slurry yield stress, were shown to be directly linked to liquefaction efficiency and to reductions in hydrolysis yield with increasing solids loading. It appeared that enzyme-mediated liquefaction of biomass was achieved through a combination of material dilution, particle fragmentation and alteration of interparticle interactions. Cellobiohydrolases and endoglucanases were shown to be the key enzymes involved in these mechanisms. However, the effectiveness of the various enzymes was strongly influenced by the s…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/66731
note: THE INFLUENCE OF ENZYMATIC LIQUEFACTION AND SLURRY RHEOLOGY ON HIGH-SOLIDS CELLULOSE HYDROLYSIS by TIMO WILLIAM VAN DER ZWAN BSc, Microbiology and Immunology, The University of British Columbia, 2013 A DISSERTATION SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Forestry) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) August 2018 © Timo William van der Zwan, 2018 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the dissertation entitled: The Influence of Enzymatic Liquefaction and Slurry Rheology on High-Solids Cellulose Hydrolysis submitted by Timo William van der Zwan in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Forestry Examining Committee: Dr. Jack Saddler, Forestry Supervisor Dr. Scott Renneckar, Forestry Supervisory Committee Member Dr. Steven Hallam, Microbiology and Immunology University Examiner Dr. Vikramaditya Yadav, Chemical and Biological Engineering University Examiner Additional Supervisory Committee Members: Dr. Paul McFarlane, Forestry Supervisory Committee Member Dr. Jinguang Hu, Bioproducts and Biosystems, Aalto University Supervisory Committee Member iii Abstract Enzyme-mediated hydrolysis of lignocellulosic materials for their conversion into bioproducts would benefit significantly if high solids concentrations (low water-to-biomass ratios) could be processed effectively. However, the fibrous nature of lignocellulosic biomass makes effective reaction mixing difficult, resulting in mass transfer limitations that reduce process yields. Overcoming these rheological challenges will require a better understanding of the substrate properties that influence slurry rheology, and in particular, how the action of carbohydrate-active enzymes can better facilitate slurry viscosity reduction, or ‘enzymatic liquefaction’. To this end, t…
has type: Thesis/Dissertation
date issued: 2018-09
is shown at: 10.14288/1.0370963
language: eng
degree discipline: Forestry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/66731