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.

本研究通过评估驱动发酵性能的八个过程变量对生产成本和温室气体排放的影响，探索通过气流发酵生产乙醇的关键成功因素。评估了三种发酵原料：来自钢铁工业的废气、木质纤维素生物质衍生的合成气以及 H ₂和 CO ₂的混合物。该分析是通过一系列 (i) 基于随机模拟的敏感性分析和 (ii) 多目标优化来完成的。在经济方面，钢铁尾气的使用导致最佳性能和最高的稳定性，以降低传质系数、微生物对乙醇的低耐受性、乙酸联产以及用 CO _{2稀释气体进料}，由于气体原料可用的温度相对较高。由这三种原料生产的乙醇导致温室气体排放低于化石汽油，并与第一代和第二代乙醇竞争。