Improved n-butanol production by a non-acetone producing Clostridium pasteurianum DSMZ 525 in mixed substrate fermentation

Abstract

The kinetics of growth, acid and solvent production in batch culture of Clostridium pasteurianum DSMZ 525 were examined in mixed or mono-substrate fermentations. In pH-uncontrolled batch cultures, the addition of butyric acid or glucose significantly enhanced n-butanol production and the ratio of butanol/1,3-propanediol. In pH-controlled batch culture at pH = 6, butyric acid addition had a negative effect on growth and did not lead to a higher n-butanol productivity. On the other hand, mixed substrate fermentation using glucose and glycerol enhanced the growth and acid production significantly. Glucose limitation in the mixed substrate fermentation led to the reduction or inhibition of the glycerol consumption by the growing bacteria. Therefore, for the optimal growth and n-butanol production by C. pasteurianum, a limitation of either substrate should be avoided. Under optimized batch conditions, n-butanol concentration and maximum productivity achieved were 21 g/L, and 0.96 g/L × h, respectively. In comparison, mixed substrate fermentation using biomass hydrolysate and glycerol gave a n-butanol concentration of 17 g/L with a maximum productivity of 1.1 g/L × h. In terms of productivity and final n-butanol concentration, the results demonstrated that C. pasteurianum DSMZ 525 is well suitable for n-butanol production from mixed substrates of biomass hydrolysate and glycerol and represents an alternative promising production strain.

Impacts of acetone on the spray combustion of Acetone–Butanol–Ethanol (ABE)-Diesel blends under low ambient temperature

“…In the current study, all the blends were mixed using individual fuels in order to control the components ratio precisely. In the future, ABE mixture could be used directly, with the components ratios controlled during the ABE fermentation process [23,24].…”

Germinants and Their Receptors in Clostridia

“…Clostridium beijerinckii can be used to produce butanol (4), while Clostridium cellulolyticum can use cellulose as a carbon source and generate lactate, acetate, and ethanol as valuable end products (5). Finally, Clostridium pasteurianum converts algal biomass to commercially useful butanol, ethanol, and propanediol (6).…”

4. Introduction to bioconversion and downstream processing: principles and process examples

“…Even though Clostridia are mostly known for n-butanol production from glucose, they are also able to produce butanol form glycerol as single substrate or in mixture with glucose [32,33]. With glucose as the main carbon source, the fermentation profile of most solventogenic Clostridia is divided into two distinct phases: acidogenic phase, in which acids and cell biomass are first produced, followed by solventogenic phase, in which most of the acids are converted to solvents.…”