This study shows that
as process pH decreased, the rate of cell growth and CO2 production also decreased, resulting in slower
fermentations, increased duration of butanol production and higher butanol concentrations and yields.
The production rate of PDO was multi-modal and the role of PDO appears to function in redox homeostasis.
The results also showed that C. pasteurianum displayed little biphasic behavior when compared to
Clostridia spp. typically used in ABE fermentation due to the alternative glycolysis-independent reductive
pathway of PDO production, rendering it suitable for a continuous fermentation process.