Application of Nanoparticles in Bioreactors to Enhance Mass Transfer during Syngas Fermentation

Abstract

Gas–liquid mass transfer is a major issue during various bioprocesses, particularly in processes such as syngas fermentation (SNF). Since SNF involves the movement of gases into the fermentation broth, there is always a rate-limiting step that reduces process efficiency. Improving this process could lead to increased efficiency, higher production of ethanol, and reduced energy consumption. One way to improve fluid transfer between gas and liquid is by incorporating nanoparticles (NPs) into the liquid phase. This entry describes recent advances in using NPs to improve gas–liquid mass transfer during SNF. The entry also describes the basics of SNF and the impact of NPs on the process and suggests areas for future research. For example, carbon nanotubes have been found to elevate the available surface area needed for gas–liquid transfer, thus improving the process efficiency. Another area is the use of NPs as carriers for enzymes involved in syngas fermentation.

A concise review of technologies for converting forest biomass to bioenergy

“…Subsequently, the syngas is subjected to the Fischer-Tropsch process to produce bioethanol (Laesecke et al, 2017). Moreover, the microbe Clostridium ljungdahlii can produce bioethanol through the utilization of syngas, facilitated by its inclusion of catalysts (Sajeev et al, 2023). Figure 4 depicts the thermochemical conversion procedure of biomass.…”

Recent Advances in the Technologies and Catalytic Processes of Ethanol Production

“…However, the issues that must be addressed in order to incorporate the syngas fermentation into an industrial-scale process include the gas-liquid mass transfer limitation brought to the low aqueous solubilities of the gaseous substrates that occur when cells have the capacity to process more gas than the bioreactor can supply. The resistance of gaseous substrate diffusion at the gas-liquid interface has been identified as the limiting step in syngas fermentation [160][161][162][163]. The other challenge identified as low carbon fixation yield, high production cost, and the effects of gaseous impurities such as NH 3 , H 2 S, and NO x even at low concentrations by limiting microbial growth, enzyme activities or by changing physiochemical conditions led to the unintended accumulation of organic acids and decreased alcohol formation [152][153][154]159,164,165].…”