Membrane bioreactors for syngas permeation and fermentation

Abstract

Syngas fermentation to biofuels and chemicals is an emerging technology in the biobased economy. Mass transfer is usually limiting the syngas fermentation rate, due to the low aqueous solubilities of the gaseous substrates. Membrane bioreactors, as efficient gas-liquid contactors, are a promising configuration for overcoming this gas-to-liquid mass transfer limitation, so that sufficient productivity can be achieved. We summarize the published performances of these reactors. Moreover, we highlight numerous parameters settings that need to be used for the enhancement of membrane bioreactor performance. To facilitate this enhancement, we relate mass transfer and other performance indicators to the type of membrane material, module, and flow configuration. Hollow fiber modules with dense or asymmetric membranes on which biofilm might form seem suitable. A model-based approach is advocated to optimize their performance.

Progress and development of syngas fermentation processes toward commercial bioethanol production

“…Increasing the surface area of the membrane per unit working volume AS/VL to 62.5 m −1 , and reducing the pressure to 37.23 kPa, achieved a higher volumetric mass transfer coefficient k La of 155.16 h −1 . 87 Elisiario et al 88 reported that silicone membranes are highly resistant to mechanical and chemical stress, unlike microporous membranes, and they are not susceptible to pore clogging, biofouling or liquid entry in the pores. 88 The simplicity of operation and control has made CSTR the most used reactor in research laboratories and industrial settings.…”

“…87 Elisiario et al 88 reported that silicone membranes are highly resistant to mechanical and chemical stress, unlike microporous membranes, and they are not susceptible to pore clogging, biofouling or liquid entry in the pores. 88 The simplicity of operation and control has made CSTR the most used reactor in research laboratories and industrial settings. 89 Table 3 provides a summary of some widely used bioreactors, presenting how they perform during syngas fermentation.…”

COx Fixation to Elementary Building Blocks: Anaerobic Syngas Fermentation vs. Chemical Catalysis

“…Trickle bed reactors have a thin liquid film contacting the gas phase and, therefore, a low liquid resistance to mass transfer [133]. Membrane reactors could reach a maximum k L a of 1096 h -1 at laboratory scale, which is three times higher than that of industrially used bubble columns [134]. However, due to the high membrane costs, they are less suitable for the production of bulk chemicals like ethanol [134].…”

“…Membrane reactors could reach a maximum k L a of 1096 h -1 at laboratory scale, which is three times higher than that of industrially used bubble columns [134]. However, due to the high membrane costs, they are less suitable for the production of bulk chemicals like ethanol [134]. Another possibility to achieve high mass transfer rates but with low operational and maintenance costs are bubble and gas-lift reactors.…”

Leveraging substrate flexibility and product selectivity of acetogens in two‐stage systems for chemical production

“…Experimental and computational system‐level analyses of a growing number of gas‐fermenting processes supported a better understanding of cellular behaviour and of its application in biocatalytic systems' development (de Lima et al, 2022 ; Ghadermazi et al, 2022 ; Mahamkali et al, 2020 ; Molitor et al, 2017 ; Valgepea et al, 2017 ). Additionally, several studies focused on the development of efficient reactor configurations combining enhanced gas‐to‐liquid mass transfer with low power consumption (Asimakopoulos et al, 2018 ; Elisiario et al, 2022 ; Stoll et al, 2019 ; Takors et al, 2018 ). Over the past several years, synthetic biology approaches have been employed to develop acetogens in efficient platform strains for C 1 gas conversion, focusing in particular on the manipulation of metabolic fluxes aimed at the production of non‐native compounds (Bourgade et al, 2021 ; Lee et al, 2022 ).…”