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Effects of enzyme feeding strategy on ethanol yield in fed-batch simultaneous saccharification and fermentation of spruce at high dry matter

Hoyer, Kerstin LU ; Galbe, Mats LU and Zacchi, Guido LU (2010) In Biotechnology for Biofuels 3.
Abstract
Background: To make lignocellulosic fuel ethanol economically competitive with fossil fuels, it is necessary to reduce the production cost. One way to achieve this is by increasing the substrate concentration in the production process, and thus reduce the energy demand in the final distillation of the fermentation broth. However, increased substrate concentration in simultaneous saccharification and fermentation (SSF) processes has been shown to result in reduced ethanol yields and severe stirring problems. Because the SSF medium is being continuously hydrolyzed, running the process in fed-batch mode could potentially reduce the stirring problems and lead to increased ethanol yields in high-solids SSF. Different enzyme feeding strategies,... (More)
Background: To make lignocellulosic fuel ethanol economically competitive with fossil fuels, it is necessary to reduce the production cost. One way to achieve this is by increasing the substrate concentration in the production process, and thus reduce the energy demand in the final distillation of the fermentation broth. However, increased substrate concentration in simultaneous saccharification and fermentation (SSF) processes has been shown to result in reduced ethanol yields and severe stirring problems. Because the SSF medium is being continuously hydrolyzed, running the process in fed-batch mode could potentially reduce the stirring problems and lead to increased ethanol yields in high-solids SSF. Different enzyme feeding strategies, with the enzymes either present in the reactor from start-up or fed into the reactor together with the substrate, have been studied, along with the influence of the enzyme feeding strategy on the final ethanol yield and productivity. Results: In the present study, SSF was run successfully with 10% and 14% water-insoluble solids (WIS) in batch and fed-batch mode. The mixing of the material in the reactor was significantly better in fed-batch than batch mode, and similarly high or higher ethanol yields were achieved in fed-batch mode compared with batch SSF in some cases. No general trend in the dependence of ethanol yield on enzyme feeding strategy was found. Conclusions: The optimum enzyme feeding strategy appears to depend on the conditions during SSF, such as the WIS concentration and the concentration of inhibitory compounds in the SSF medium. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Biotechnology for Biofuels
volume
3
publisher
BioMed Central
external identifiers
  • wos:000280326300001
ISSN
1754-6834
DOI
10.1186/1754-6834-3-14
language
English
LU publication?
yes
id
2ebf0a8b-6dad-44e7-ad18-c148a471fd56 (old id 1656846)
alternative location
http://www.biotechnologyforbiofuels.com/content/3/1/14
date added to LUP
2010-08-31 10:46:06
date last changed
2018-05-29 09:45:06
@article{2ebf0a8b-6dad-44e7-ad18-c148a471fd56,
  abstract     = {Background: To make lignocellulosic fuel ethanol economically competitive with fossil fuels, it is necessary to reduce the production cost. One way to achieve this is by increasing the substrate concentration in the production process, and thus reduce the energy demand in the final distillation of the fermentation broth. However, increased substrate concentration in simultaneous saccharification and fermentation (SSF) processes has been shown to result in reduced ethanol yields and severe stirring problems. Because the SSF medium is being continuously hydrolyzed, running the process in fed-batch mode could potentially reduce the stirring problems and lead to increased ethanol yields in high-solids SSF. Different enzyme feeding strategies, with the enzymes either present in the reactor from start-up or fed into the reactor together with the substrate, have been studied, along with the influence of the enzyme feeding strategy on the final ethanol yield and productivity. Results: In the present study, SSF was run successfully with 10% and 14% water-insoluble solids (WIS) in batch and fed-batch mode. The mixing of the material in the reactor was significantly better in fed-batch than batch mode, and similarly high or higher ethanol yields were achieved in fed-batch mode compared with batch SSF in some cases. No general trend in the dependence of ethanol yield on enzyme feeding strategy was found. Conclusions: The optimum enzyme feeding strategy appears to depend on the conditions during SSF, such as the WIS concentration and the concentration of inhibitory compounds in the SSF medium.},
  author       = {Hoyer, Kerstin and Galbe, Mats and Zacchi, Guido},
  issn         = {1754-6834},
  language     = {eng},
  publisher    = {BioMed Central},
  series       = {Biotechnology for Biofuels},
  title        = {Effects of enzyme feeding strategy on ethanol yield in fed-batch simultaneous saccharification and fermentation of spruce at high dry matter},
  url          = {http://dx.doi.org/10.1186/1754-6834-3-14},
  volume       = {3},
  year         = {2010},
}