Acetone, butanol, and ethanol

Separation of citric acid from fermentation broth Separation of lactic acid from fermentation broth Production of acetone, butanol, and ethanol (ABE) from potato wastes Separation of long-chain unsaturated fatty acids... 

To compare the performance of the reactor and evaluate the effect of CSL incorporation into the feed, the reactor was fed with CSL medium. Fermentation conditions and the dilution rate were kept constant as in Table 1 for the duration of this experiment. The reactor produced 6.29 g/L of total ABE, of which acetone, butanol, and ethanol were 2.00, 4.16, and 0.13 g/L, respectively (Table 1). This resulted in a productivity of 2.01 g/(L h) and a sugar utilization of 30.5% of that available in the feed (67.5 g/L). Compared to the control, the productivity was reduced by 10%. However, it is anticipated that it would be economical to use CSL compared with the P2 medium. This demonstrated that P2 medium can be replaced by economically available CSL. It is suggested, however, that the CSL... 

Next, an experiment was run in which 2.5 g/L of sodium butyrate was added to P2 medium to investigate whether it could be converted to butanol. A control experiment was run containing P2 medium. A separate control experiment was run before each experiment. This is essential because biomass accumulation in the reactor changes with time, thus affecting performance of the reactor (5). The reactor produced 4.77 g/L of total ABE, of which acetone, butanol, and ethanol were 1.51,3.14, and 0.12 g/L, respectively (Table 1). It resulted in a total ABE productivity of 1.53 g/(L-h) and a glucose utilization of 29.4% of that available in the feed of 59.1 g/L. The acid concentration in the effluent was 1.56 g/L. Following this, P2 medium was supplemented with sodium butyrate and the experiment was conducted at the same dilution rate. The reactor produced 1.55 g/L of acetone, 4.04 g/L of butanol, and 0.11 g/L of ethanol, for a total ABE concentration of 5.70 g/L, compared with 4.77 g/L in the control experiment. The productivity was 1.82 g/(L-h), compared with 1.53 g/(L-h) for the control experiment. These experiments suggested that butyrate was used by the culture to produce additional butanol. Note that 0.9 g/L of butanol was produced from 1.65 g/L of butyrate (2.5 g/L in feed, 0.85 g/L in effluent). The yield calculations do not include the amount of butyrate that was utilized by the culture. 

In 1999, the domestic demand for butanol was 841,000 metric t and it is projected to increase 3% per year (49). During the early twentieth century, the primary method of butanol production was anaerobic fermentation with Clostridium acetobutylicum to produce a mixture of acetone, butanol, and ethanol. The butanol yields were low, and as oil prices declined after World War II, petrochemical routes to butanol displaced the fermentation route (50). The primary petrochemical route used today involves the hydrogenation of n-butyraldehyde (49), and production costs hover around 0.66/kg (24). 

After 606 h, the dilution rate in reactor L was decreased from 1.2 to 0.6 hr1. When the pH was adjusted to 3.5 at 623 h, the concentrations of acetone, butanol, and ethanol decreased dramatically and reduced to almost 0 g/L by 700 h (see Fig. 4A). In the meantime, the concentrations of glucose and butyric acid increased with time to reach almost their feed concentrations. Coupled with the low OD value, these findings make it apparent that the fermentation had almost ceased at this low pH value. 

ABE (acetone, butanol, and ethanol) fermentation has a long history of commercial use and perhaps the greatest potential for an industrial comeback. Acetone, butanol, and ethanol can all be isolated from this remarkable metabolic system carbon dioxide and hydrogen are additional products. The solvents were used as paint solvents in the expanding automobile industry. Ultimately these processes proved uncompetitive because of poor yields, low product... 

Kawedia JD, Pangarkar VG, and Niranjan K. Pervaporative stripping of acetone, butanol and ethanol. Bioseparation. 2000 9 (3) 145-154. 

One of the most fascinating stories of the coatings industry involves the production of acetone, butanol, and ethanol by the Weizmann process (11. 12). Because the main objective was to produce acetone for explosives, the butanol piled up until it was found that butyl acetate was an excellent solvent for the new nitrocellulose lacquers. Commercial Solvents Corporation (of Maryland) was formed in 1919 to take over the fermentation plants operating at Terre Haute to make butanol and derivatives. The availability of butyl alcohol and the acetate was of major aid in the success of nitrocellulose lacquers in new automobile paints that permitted a reduction in the time required for painting automobiles from 23 days in 1920 to a matter of about 12 h in 1940 (13). 

C. acetohutylicum ATCC 824 is able to ferment glucose, lactose, sucrose, levulose, galactose, mannose, arabinose, xylose, starch, pectin, inulin, mannitol, glycogen, dextrin, melezitose [21], amygdalin, and rafiinose and it produces the solvents acetone, butanol, and ethanol [23]. 

PEBA membrane was used for separation of acetone, butanol, and ethanol from aqueous solution. 

IzaK, P., Schwarz, K., Ruth, W., Bahl, H., Kragl, U. (2008). Increased productivity of Clostridium acetobutylicum fermentation of acetone, butanol, and ethanol by pervaporation through supported ionic liquid membrane. Applied Microbiology and Biotechnology, 78, 597—602. 

As described above, the clostridial ABE fermentative path leads to synthesis of butanol, together with smaller amounts of acetone, ethanol and acetic and butyric acids, together with carhon dioxide and hydrogen (Branduardi et al. 2014). Normally, the solvent ratio of acetone, butanol and ethanol, respectively, is 3 6 1, and the total solvent concentration is around 20 g/L (Connor and Liao 2009). Many natural clostridial strains have the upper butanol tolerance limit at about 11-12 g/L. However, some mutants and engineered strains can tolerate up to 19 g/L of butanol (Jang et al. 2012a). 

Weizmann process A fermentation process used to produce acetone, butanol, and ethanol using the acid-resistant bacterium Clostridium acetobutylicum. The bacteria derived from soil and cereals is able to convert whey, sugar, and starch. The process was developed by Russian-born chemist Chaim Weizmann (1874-1952) and was used in the UK in the First World War for the production of acetone, which was used in the production of cordite. He became a UK citizen in 1910 and then the first president of Israel in 1949. The process is also known as the ABE fermentation. 

The fermentation of carbohydrates to acetone, butanol, and ethanol by solventogenic Clostridia is known for decades. Clostridia produce butanol by conversion of a suitable carbon source into acetyl-CoA. Substrate acetyl-CoA then enters into the solventogenesis pathway to produce butanol using six concerted enzyme reactions. The solvent production process according to the invention comprises of culturing a fast growing microorgan-... 

Acetone, butanol, and ethanol lai e-scale fermentation in England... 

Butanol (C4H9OH) is an alcohol produced from starch through ABE fermentation (ie, using acetone, butanol, and ethanol). It can be used in gasoline engines without modifications. 

Huang et al. (2015c) evaluated acetone, butanol, and ethanol (ABE) fermentation from food waste with and without the use of a vacuum recovery system. Using 129 g/L food waste-based medium, 19.7 g/L of ABE was produced in 48 h without a vacuum system. Glucose concentration peaked at 28.5 g/L at 15 h, and stabilized at 22 g/L after 24 h. ABE productivity of 0.41 g/L-h was observed. At the end of fermentation 21.7 g/L of residual glucose was left in the fermentation broth (Fig. 9.8). When... 

Pervaporation is a membrane-based product recovery technique. In this process, membrane is used to selectively separate volatile compounds (eg, ethanol and butanol). Volatile compounds in the liquid diffuse through the membrane and evaporate into vapor, and are collected by condensation (Yang and Lu, 2013). A partial pressure difference across the membrane is required to volatilize permeates into vapor. Polydimethylsilox-ane (PDMS) membrane has been extensively used for pervaporation separation of acetone, butanol, and ethanol (Liu et al., 2005). 

A hybrid process that combines membrane separation and distillation for bioethanol and biobutanol production is being worked on by MTR [88, 89]. The membrane units use either vapor permeation or PV. The BioSep processes offer more than 50% energy savings and are cost competitive with respect to conventional distillation-molecular sieve technology. They are attractive when the ethanol concentration in the fermentation step is low, such as in cellulose-to-ethanol and algae-to-ethanol. In the case of biobutanol production, the membrane systems concentrate and dehydrate the acetone, butanol and ethanol mixture, saving up to 87% of the energy required to recover biobutanol by conventional separation techniques. 

Elhs JT, Hengge NN, Sims RC, Miller CD. Acetone, butanol, and ethanol production firom wastewater algae. Bioresour Technol. 2012 111 491—495. 

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