Microbial synthesis gas utilization and ways to resolve kinetic and mass-transfer limitations

Microbial conversion of syngas to energy-dense biofuels and valuable chemicals is a potential technologyfor the efficient utilization of fossils (e.g., coal) and renewable resources (e.g., lignocellulosic biomass) inan environmentally friendly manner. However, gas–liquid mass transfer and kinetic limitations are stillmajor constraints that limit the widespread adoption and successful commercialization of the technology.This review paper provides rationales for syngas bioconversion and summarizes the reaction limitedconditions along with the possible strategies to overcome these challenges. Mass transfer and economicperformances of various reactor configurations are compared, and an ideal case for optimum bioreactoroperation is presented. Overall, the challenges with the bioprocessing steps are highlighted, and potentialsolutions are suggested. Future research directions are provided and a conceptual design for amembrane-based syngas biorefinery is proposed