Bioprocess development for biochemical conversion of lignocellulose
Doctoral thesis, 2017
Lignocellulose
strain engineering
stress tolerance
kinetic modelling
high gravity
scale-up
biofuels
SSCF
process development
Saccharomyces cerevisiae
Author
Ruifei Wang
Industrial biotechnology
Model-based optimization and scale-up of multi-feed simultaneous saccharification and co-fermentation of steam pre-treated lignocellulose enables high gravity ethanol production.
Biotechnology for Biofuels,;Vol. 9(2016)p. 88-
Journal article
Kinetic modeling of multi-feed simultaneous saccharification and co-fermentation of pretreated birch to ethanol
Bioresource Technology,;Vol. 172(2014)p. 303-311
Journal article
Westman, J.O, Wang R.,, Novy, V., and Franzén C.J. Sustaining fermentation in high-gravity ethanol production by feeding yeast to a temperature-profiled simultaneous saccharification and co-fermentation of wheat straw
Wang R., Lorantfy B., Fusco S.,, Olsson L., and Franzén C.J. Comparative analysis of quantitative methods for assessing yeast cell concentrations in lignocellulosic media
In this thesis, we have employed a systematic, model-driven approach to the design of feeding schemes of solid substrate, adapted yeast cells, and enzymes to fed-batch simultaneous saccharification and co-fermentation (Multi-Feed SSCF) of pretreated lignocellulosic materials. With this approach, mixing problems were avoided at high solid loadings, leading to an ethanol concentration of 50-55 g/L within 72 hours of SSCF on wheat straw. A similar fermentation performance was obtained at a 10 qubic-meter demonstration scale using several yeast strains. Key factors for an efficient lignocellulose-based bioprocess were characterised, including rapid medium liquefaction and sustained yeast viability during the SSCF process. I investigated possible strategies to circumvent the limitations to SSCF posed by limited thermotolerance of the yeast Saccharomyces cerevisiae. The concentration of active cells determines the quality of fermentation processes. I assessed the applicability of several methods for quantitative analysis of both total and viable cells in complex lignocellulosic media. In conclusion, this study established a production workflow for the conversion of pretreated lignocellulosic materials to chemicals and fuels.
Subject Categories
Industrial Biotechnology
Other Engineering and Technologies not elsewhere specified
Biological Sciences
Bioprocess Technology
Areas of Advance
Energy
Life Science Engineering (2010-2018)
ISBN
978-91-7597-603-7
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4284
Publisher
Chalmers
KA
Opponent: Associate Prof. Anna Eliasson Lantz, Technical University of Denmark, Denmark