Influence of nutritional and operational parameters on the production of butanol or 1,3-propanediol from glycerol by a mutant Clostridium pasteurianum

Abstract

Butanol and 1,3-propanediol (1,3-PDO) are simultaneously produced by Clostridium pasteurianum from glycerol. In this study, random chemical mutagenesis of C. pasteurianum DSM 525 was conducted to improve its tolerance to butanol. Selected nutritional and operational parameters were evaluated to identify strategies that favour the production of each metabolite. From those experiments, it was possible to isolate cells able to produce 22% more butanol than the parent strain in serum bottles. The supplementation of the culture medium with 2mgl of iron increased the production of butanol by 163%, and the optimum inoculum age was found to be 12hours. Overall, the experiments conducted in bioreactor led to lower butanol titers than in serum bottles, which is attributed to the higher pressure present in the bottles. At pH 6.0, N sparging notoriously favoured the production of biomass and 1,3-PDO, while a lower pH (5.0) led to a higher butanol yield, although growth was negatively affected. The results herein gathered allowed the identification of specific conditions that favour the production of either butanol or 1,3-PDO. Furthermore, it was found that N sparging is a suitable strategy to maximize the titer, yield and productivity of 1,3-PDO using C. pasteurianum.

Exploitation of novel wild type solventogenic strains for butanol production

“…strains Strain Substrate Fermentation pattern Solvents (g/L) References Clostridium sp. strain BOH3 Xylose Acetone–butanol–ethanol (ABE) 5.32 g/L acetone, 14.94 g/L butanol, 1.25 g/L ethanol [ 34 ] C. tetanomorphum strain DSM665 Glucose Butanol–ethanol (BE) 9.81 g/L butanol, 1.01 g/L ethanol [ 20 ] C. pasteurianum DSM 525 Glycerol Butanol–propanediol 7.13 g/L butanol, 6.79 g/L 1,3-propanediol [ 44 ] Clostridium sp. BT10-6 Glucose Isopropanol 5.26 g/L isopropanol [ 23 ] Clostridium sp.…”

“…Currently, C. pasteurianum DSM 525 was the most commonly used one for butanol production from glycerol. 7.13 g/L of butanol and 6.79 g/L of 1,3-propanediol could be produced from 46.38 g/L of glycerol by C. pasteurianum DSM 525 [ 44 ]. After fermentation process optimization, the final butanol and 1,3-propanediol titers could be further improved to 13.92 g/L and 5.34 g/L, respectively [ 45 ].…”

Genetically Engineered Strains: Application and Advances for 1,3-Propanediol Production from Glycerol

“…Two plates without the mutagen were used as the control. After several minutes, liquid strain culture was spread on each plate, which were then incubated until bacterial growth was observed (68).…”

“…The first is to continuously conduct mutagenesis generation by generation (69). The second is to carry out stress treatment by adding the inhibitors like glycerol and 1,3-PD into the fermentation broth (68). However, the most promising technique is immobilization of cells (31).…”

Comprehensive investigations of biobutanol production by a non-acetone and 1,3-propanediol generating Clostridium strain from glycerol and polysaccharides

“…Its abundance and cost competitiveness make glycerol an excellent alternative to other carbon substrates for butanol production. Unfortunately, the most studied bacteria for biobutanol production, such as C. acetobutylicum and C. beijerinckii , can not grow solely in glycerol as it can not re-oxidize the excess NADH generated in the cellular glycerol catabolism [ 8 , 9 ]. Currently, C. pasteurianum is the only solventogenic Clostridium species which possess the metabolic pathway needed for glycerol metabolism.…”