Ethanol Metabolism Dynamics in Clostridium ljungdahlii Grown on Carbon Monoxide
Ziyong Liu, Dechen Jia, Kun-Di Zhang, Haifeng Zhu, Quan Zhang, Weihong Jiang, Yang Gu, Fuli Li
Abstract
Ethanol production from carbon monoxide (CO) as a carbon and energy source by Clostridium ljungdahlii and “ Clostridium autoethanogenum ” is currently being commercialized. During gas fermentation, ethanol synthesis is NADH-dependent. However, ethanol oxidation and its regulatory mechanism remain incompletely understood. Energy metabolism analysis demonstrated that reduced ferredoxin is the sole source of NADH formation by the Rnf-ATPase system, which provides ATP for cell growth during CO fermentation. Therefore, ethanol production is tightly linked to biomass production (ATP production). Clarification of the mechanism of ethanol oxidation and biosynthesis can provide an important reference for generating high-ethanol-yield strains of C. ljungdahlii in the future.