Continuous Production of Butanol by <I>Clostridium acetobutylicum </I> Immobilized in a Fibrous Bed Bioreactor

Abstract

We explored the influence of dilution rate and pH in continuous cultures of Clostridium acetobutylicum. A 200-mL fibrous bed bioreactor was used to produce high cell density and butyrate concentrations at pH 5.4 and 35degreesC. By feeding glucose and butyrate as a cosubstrate, the fermentation was maintained in the solventogenesis phase, and the optimal butanol productivity of 4.6 g/(L h) and a yield of 0.42 g/g were obtained at a dilution rate of 0.9 h-1 and pH 4.3. Compared to the conventional acetone-butanol-ethanol fermentation, the new fermentation process greatly improved butanol yield, making butanol production from corn an attractive alternative to ethanol fermentation.

Butanol production by Clostridium acetobutylicum in a continuous packed bed reactor

“…Mindful of the experience of pH increase from 4.0 to 4.3, the pH further increased at 5.0. After about 4 days of acclimatization to the new operating conditions, the D was set at 0.97 h -1 , in agreement with previous investigations that pointed out high solvent productivities at values of D & 1 h -1 [9,21,26]. The biofilm PBR approached a new steady-state condition (t & 616 h) and it was successfully operated for a further 134 h (about 140 space-time).…”

“…Several attempts are reported in the literature regarding continuous fermentation by means of Clostridia strains confined in the reactor by immobilization [5,9,15,20,22,24]. A variety of supports have been employed for biofilm development, such as sand [7,8], granular activated carbon [11], anthracite coal [12], plastics [19], and various kinds of clays [22].…”

Effect of Buffering System on Acetone-Butanol-Ethanol Fermentation by Clostridium acetobutylicum ATCC 824 using Pretreated Oil Palm Empty Fruit Bunch

“…Thus, many studies have been conducted to find a suitable pH value for solvent production and to control the pH at the same time so that suitable amounts of acids are produced for the solventogenic phase (Huang et al 2004;Li et al 2011;Guo et al 2012). The use of buffer was believed to be the simplest way to control pH conditions in batch fermentation while simultaneously providing the chance for cells to switch from the acidogenic to the solventogenic phase (Lee et al 2008).…”

Continuous acetone–butanol–ethanol production by corn stalk immobilized cells

“…Many researchers [12,13] found that clostridium can automatically stick to the lignocellulosic material and grow on the support without any additional chemicals. The porosity of corn stalk makes the cells not only grow on the surface of the support, but also in the inner side of the supports, resulting in a much higher cell density or cell loading.…”

“…One of the most extensively used classes of natural support is lignocellulosic materials. Some lignocellulosic supports being investigated include sawdust, wood chips/shavings, rice husks, cotton towels, and straw [10][11][12][13][14]. The corn stalk is a readily available and inexpensive material with many advantages as a support material for cell immobilization.…”