A Mini-Review on Syngas Fermentation to Bio-Alcohols: Current Status and Challenges

Biomass gasification produces syngas, mainly comprised of CO and H-2 along with H2S, CO2, N-2,N- and tar compounds. Inorganic carbon present in syngas as CO and CO2 can be utilized for the production of several value-added chemicals including ethanol, higher alcohols, fuels, and hydrogen. However, chemical sequestration operates at a high temperature of 300-500 degrees C and pressure of 3-5 MPa in the presence of heavy metal catalysts. Catalyst regeneration and the maintenance of high temperature and pressure increased the cost of operation. Microorganisms like algae and bacteria including Acetobacterium and Clostridium also have the potential to sequester carbon from the gas phase. Research has emphasized the production of microbial metabolites with a high market value from syngas. However, scale-up and commercialization of technology have some obstacles like inefficient mass transfer, microbial contamination, inconsistency in syngas composition, and requirement for a clean-up process. The current review summarizes the recent advances in syngas production and utilization with special consideration of alcohol and energy-related products along with challenges for scale-up.

Automated summary

Biomass gasification produces syngas containing CO, H2, H2S, CO2, N2, N, and tar compounds. The carbon in syngas can be utilized for the production of valuable chemicals, but chemical sequestration requires high temperature and pressure with heavy metal catalysts. Microorganisms like algae and bacteria have the potential for carbon sequestration. However, scale-up and commercialization face challenges such as mass transfer inefficiency, microbial contamination, inconsistent syngas composition, and the need for a clean-up process. This review summarizes recent advances and challenges in syngas production and utilization, with a focus on alcohol and energy-related products.