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Mitigation of pretreatment-derived inhibitors during lignocellulosic ethanol fermentation using spent grain as a nitrogen source

Persson, Michael LU ; Galbe, Mats LU and Wallberg, Ola LU (2021) In Biomass Conversion and Biorefinery
Abstract

Nitrogen-containing nutrient sources can be used to mitigate the negative effects of pretreatment-derived inhibitors on product formation rates during bioethanol production. Process economic limitations require these nutrients to be inexpensive. A method of hydrolyzing the protein in the spent grain fraction remaining after wheat grain saccharification, using porcine pancreas trypsin, is presented. This protein hydrolysate was shown to increase the volumetric productivity of ethanol production, measured after 24 h, during fermentation of a lignocellulosic hydrolysate from 0.24 to 0.60 g/L h. Although the effects on the productivity, on a per gram basis, were lower than with yeast extract, which increased the product formation rate to... (More)

Nitrogen-containing nutrient sources can be used to mitigate the negative effects of pretreatment-derived inhibitors on product formation rates during bioethanol production. Process economic limitations require these nutrients to be inexpensive. A method of hydrolyzing the protein in the spent grain fraction remaining after wheat grain saccharification, using porcine pancreas trypsin, is presented. This protein hydrolysate was shown to increase the volumetric productivity of ethanol production, measured after 24 h, during fermentation of a lignocellulosic hydrolysate from 0.24 to 0.60 g/L h. Although the effects on the productivity, on a per gram basis, were lower than with yeast extract, which increased the product formation rate to 1.64 g/L h, amino acid analysis of the soluble polypeptides in the protein hydrolysate showed that the feasibility of using spent grain as a nutrient source could be increased through optimization of the hydrolysis step. Furthermore, it was shown that pretreatment-derived inhibitors could reduce cell growth without affecting ethanol formation rates and that nutrient addition could increase ethanol formation rates without increasing cell growth. Finally, it was shown that the ability of nutrients to affect the product formation rate was limited above a certain inhibitor concentration.

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publication status
epub
subject
keywords
Ethanol, Inhibitors, Lignocellulosic biomass, Nutrients, Saccharomyces cerevisiae, Spent grains
in
Biomass Conversion and Biorefinery
publisher
Springer
external identifiers
  • scopus:85103346970
ISSN
2190-6815
DOI
10.1007/s13399-021-01454-5
language
English
LU publication?
yes
id
63c32e57-f689-4867-a44e-b0f443441b27
date added to LUP
2021-04-08 11:57:48
date last changed
2021-04-27 03:58:43
@article{63c32e57-f689-4867-a44e-b0f443441b27,
  abstract     = {<p>Nitrogen-containing nutrient sources can be used to mitigate the negative effects of pretreatment-derived inhibitors on product formation rates during bioethanol production. Process economic limitations require these nutrients to be inexpensive. A method of hydrolyzing the protein in the spent grain fraction remaining after wheat grain saccharification, using porcine pancreas trypsin, is presented. This protein hydrolysate was shown to increase the volumetric productivity of ethanol production, measured after 24 h, during fermentation of a lignocellulosic hydrolysate from 0.24 to 0.60 g/L h. Although the effects on the productivity, on a per gram basis, were lower than with yeast extract, which increased the product formation rate to 1.64 g/L h, amino acid analysis of the soluble polypeptides in the protein hydrolysate showed that the feasibility of using spent grain as a nutrient source could be increased through optimization of the hydrolysis step. Furthermore, it was shown that pretreatment-derived inhibitors could reduce cell growth without affecting ethanol formation rates and that nutrient addition could increase ethanol formation rates without increasing cell growth. Finally, it was shown that the ability of nutrients to affect the product formation rate was limited above a certain inhibitor concentration.</p>},
  author       = {Persson, Michael and Galbe, Mats and Wallberg, Ola},
  issn         = {2190-6815},
  language     = {eng},
  publisher    = {Springer},
  series       = {Biomass Conversion and Biorefinery},
  title        = {Mitigation of pretreatment-derived inhibitors during lignocellulosic ethanol fermentation using spent grain as a nitrogen source},
  url          = {http://dx.doi.org/10.1007/s13399-021-01454-5},
  doi          = {10.1007/s13399-021-01454-5},
  year         = {2021},
}