Acetone–butanol–ethanol (ABE) fermentation using Clostridium acetobutylicum XY16 and in situ recovery by PDMS/ceramic composite membrane

A carbon nanotube filled polydimethylsiloxane hybrid membrane for enhanced butanol recovery

“…The presence of CNTs led to higher permeation, as well as a faster rate of mass transfer for the removal of volatile organics, such as dichloromethane, chloroform, benzene, trichloroethylene and toluene, from water. The PDMS composite membranes with high hydrophobicity and good thermal, chemical, and mechanical stability also showed excellent performance over the PVDF membranes910. In addition, the CNTs/PDMS composite materials have been used and well studied for gas separation, nanosensors and electrodes13171819.…”

“…Among them, pervaporation is a membrane-based technology with great potential to recover solvents from the dilute fermentation broth with low energy consumption910. One of the main challenges faced by pervaporation is its deficiencies in desirable permeation flux, chemical resistance and butanol selectivity.…”

Efficient acetone–butanol–ethanol (ABE) production by a butanol-tolerant mutant of Clostridium beijerinckii in a fermentation–pervaporation coupled process

“…Table 2 summarizes the reported results of PV coupled ABE fermentation process. Inhibition from butanol in fermentation-PV coupled process was reported and ABE productivity was 0.38 g/(L h) due to the presence of 7 g/L butanol in fermenter [31]. Although improving membrane flux [34] or increasing the membrane area [26] could increase solvent productivity to the level of 0.58 and 0.50 g/(L h), it would increase the ABE production cost too.…”

“…The two strains were exposed to different concentration of butanol for 72 h in sealed anaerobic bottles containing culture medium. It was reported that butanol concentration in fermenter integrated with pervaporation varied from 4 to 9 g/L [31], and therefore filtered butanol was added to culture medium to reach the desired concentration of 4 g/L, 6 g/L, 8 g/L, 10 g/L, and 12 g/L. The final cell density (OD 600 ) was detected to evaluate the butanol tolerance of the two strains.…”

“…Among all the in situ removal techniques, pervaporation is a separation process where a binary or multi-component liquid mixture is separated by partial vaporization through a membrane and is regarded as a promising process for separating ABE solvents [15]. The butanol concentration in fermentation broth could be controlled at the level ranging from 4 to 9 g/L by pervaporation [31,33], but inhibition from butanol can be noticed at concentrations as low as 5 g/L in ABE fermentation [25]. Although pervaporation could relieve the inhibition from butanol, cells still suffer greatly, which could be seen from the low solvent productivity in PV coupled fermentations [4,10].…”