Decarbonizing ethanol production via gas fermentation: Impact of the CO/H2/CO2 mix source on greenhouse gas emissions and production costs

Eduardo Almeida Benalcázar*, Henk Noorman, Rubens Maciel Filho, John A. Posada

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)
154 Downloads (Pure)


This study explores key success factors for ethanol production via fermentation of gas streams, by assessing the effects of eight process variables driving the fermentation performance on the production costs and greenhouse gas emissions. Three fermentation feedstocks are assessed: off-gases from the steel industry, lignocellulosic biomass-derived syngas and a mixture of H2 and CO2. The analysis is done through a sequence of (i) sensitivity analyses based on stochastic simulations and (ii) multi-objective optimizations. In economic terms, the use of steel off-gas leads to the best performance and the highest robustness to low mass transfer coefficients, low microbial tolerance to ethanol, acetic-acid co-production and to dilution of the gas feed with CO2, due to the relatively high temperature at which the gas feedstock is available. The ethanol produced from the three feedstocks lead to lower greenhouse gas emissions than fossil-based gasoline and compete with first and second generation ethanol.

Original languageEnglish
Article number107670
Number of pages17
JournalComputers and Chemical Engineering
Publication statusPublished - 2022


  • Bubble column
  • Ethanol
  • Gas fermentation
  • Process optimization
  • Sensitivity analysis
  • Syngas

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