Butanol fermentation

Godia, F., Adler, H. I., Scott, C. D., and Davison, B. H., Use of Immobilized Microbial Membrane Fragments to Remove Oxygen and Favor the Acetone-Butanol Fermentation, Biotechnol. Prog., 6 210 (1990)... 

Kansiz et al. has published a paper wherein they used MIR and sequential injections to monitor an acetone-butanol fermentation process.17 In this work, acetone, acetate, n-butanol, butyrate, and glucose were analyzed automatically, using computer-controlled sampling techniques. In this case, gas chromatography was the reference method. The SEPs for the components were acetone, 0.077 acetate, 0.063 butyrate, 0.058 -butanol, 0.301 and glucose, 0.493 g/1. The authors state that the precision and accuracy of the MIR methods were as good as the reference method. 

More than seventy years ago the impressive discovery was made that bioreduction of mannitol, glycerol and starch yields butanol. Fermentations in which butyric acid, butanol and acetone are formed from carbohydrates by different bacilli (butyl bacteria) belong in this group. The term butyl bacteria as a generic name for microbes producing the genetically related substances of the four-carbon series was proposed in 1921" and has been applied since then. The approximate course of these reactions is shown by the following formulations which, however, do not explain the mechanism ... 

The ethyl alcohol fermentation is of course an age-old process and is so well known that little need be said about it here. The acetone-butanol fermentation is perhaps the next most important industrial fermentation process, although starch in the form of maize has been largely used as the basic material more recently suitably treated molasses has been used. The fermentation, a relatively rapid process requiring about thirty hours, produces about 60 parts of butanol, 30 parts of acetone and 10 parts of ethyl alcohol. These products already have large uses in industry and other uses are being explored. One possibility is the use of butanol in motor fuel. Jean has described a fuel, called Jeanite, consisting mainly of butanol and ethyl alcohol, which shows some promise. Of course the admixture of ethyl alcohol with petroleum is well known and an increased use of this mixture is probable. 

Although acetone is used widely as an industrial solvent, nevertheless it has become the by-product of the acetone-butanol fermentation and there is always the fear of overproduction. There is thus a need for an extension of the industrial utilization of acetone. A possibility in this direction may be in its conversion into pinacol, the preparation of which has recently been improved by McHenry, Drum and O Connor. It is obtained together with isopropyl alcohol by electrolytic reduction of acetone under controlled conditions. Pinacol (LXVI) may be dehydrated to 2,3-dimethylbutadiene which can be converted into a synthetic rubber, or converted through pinacolone (LXVII) into neohexane... 

The butanol-acetone fermentation, using whey supplemented with yeast extract, is substantially a butanol fermentation. Volatile solvents from the fermentation consist of 80% butanol, 13% acetone, and 5% ethanol. Approximately 30% of the lactose that is fermented is converted to butanol, 5% to acetone, 2% to ethanol, and the balance largely to CO2 and small quantities of butyric and acetic acids, acetyl-methylcarbinol, and hydrogen. 

Davies, R. 1943. Studies on the acetone-butanol fermentation. IV. Acetonacetic acid decarboxylase of Clostridium acetobutylicum (BY). Biochem. J. 37, 230-238. 

Corn steep liquor (CSL), a byproduct of the com wet-milling process, was used in an immobilized cell continuous biofilm reactor to replace the expensive P2 medium ingredients. The use of CSL resulted in the production of 6.29 g/L of total acetone-butanol-ethanol (ABE) as compared with 6.86 g/L in a control experiment. These studies were performed at a dilution rate of 0.32 hr1. The productivities in the control and CSL experiment were 2.19 and 2.01 g/(Lh), respectively. Although the use of CSL resulted in a 10% decrease in productivity, it is viewed that its application would be economical compared to P2 medium. Hence, CSL may be used to replace the P2 medium. It was also demonstrated that inclusion of butyrate into the feed was beneficial to the butanol fermentation. A control experiment produced 4.77 g/L of total ABE, and the experiment with supplemented sodium butyrate produced 5.70 g/L of total ABE. The butanol concentration increased from 3.14 to 4.04 g/L. Inclusion of acetate in the feed medium of the immobilized cell biofilm reactor was not found to be beneficial for the ABE fermentation, as reported for the batch ABE fermentation. 

The present study on butanol fermentation has been focused primarily on the effects of pH and dilution rate (D) in continuous cultures of the mutant strain from C. acetobutylicum ATCC 55025. To overcome the problems of low productivity and yield of butanol, cell immobilization in a convoluted fibrous bed bioreactor (FBB) and feeding with dextrose and butyric acid as cosubstrates to produce butanol and reduce production of ancillary byproducts were used in the fermentation. By changing the dilution rate from 0.1 to 1.2 h 1 at pH 4.3 and varying the pH from 3.5 to 5.5 at the dilution rate of 0.6 hr1, the optimal conditions for high productivity and butanol yield were investigated. 

Ezeji, T.C., Qureshi, N. and Blaschek, H.P. 2007a. Butanol Production from Agricultural Residues Impact of Degradation Products on Clostridium Beijerinckii Growth and Butanol Fermentation. Biotechnol. Bioeng., 97, 1460-1469. 

Marchal, R., Blanchet, D., and Vandecasteele, J.P, Industrial optimization of acetone-butanol fermentation a study of the utilization of Jerusalem artichokes, Appl. Microbiol. Biotechnol., 23, 92-98, 1985. 

Joint use of acetone-butanol fermentation and alcoholic fermentation for the conversion of sugar-yielding plants into a mixture of butanol, acetone, and ethanol... 

The second is the direct production pathway characteristic of the acetone-butanol fermentation by bacteria such as Clostridium butyricum. In this pathway, hydrogen is produced directly without formate production. This pathway, however, may be unified with NADH pathway, because the mass balance of NADH (Nicotinamide Adenine Dinucleotide, reduced form) shows the same result with NADH pathway. 

Another industrial source of 1-butanol is the acetone-butanol fermentation of sugars - or polysaccharides. 

Due to the special situation in the post-war era, the implementation of this endeavor was extremely difficult. With the help of a French chemist, Captain Rambaud, of the French occupation forces, a small team of scientists and engineers succeeded in producing sufficiently pure penicillin within a rather short period of time (1948). Problems of equipment were solved by using various redundant military materials, e.g. V2 missile containers as liquid vessels, self-produced fermenters stirred with the help of motors of submarines and aerated by compressors powered by motors of German Tiger tanks. The necessary pipes were obtained from a bombed Innsbruck cafe. Since corn-steep liquor was not available, yeast extract had to be used, and whey had to serve as a substitute for lactose. Even the necessary butanol for the preparation of the extractant had to be produced by installing a butanol fermentation. 

Growth Inhibition Kinetics for the Acetone-Butanol Fermentation... 

The inhibitory effect of each fermentation product on the cell growth rate and the kinetics of product formation was studied for the acetone-butanol fermentation with Clostridium acetobutylicum ATCC 824. Inhibition of cell growth was studied by challenging cultures with varying concentrations of each product. There was a threshold concentration which must be reached before growth inhibition occurred. This concentration was found to vary with each inhibitor. Above the threshold concentration, there was a linear decrease of the growth rate with an increase in product concentration. 

Product Challenged Growth Studies. To study the inhibitory factors of the acetone-butanol fermentation, the growth rates of Cl. acetobutylicum in the presence of each fermentation product were determined. The end products used in this study included ethanol, butanol, acetone, acetic acid, and butyric acid. From the slopes of the least squares regression lines of optical density vs. time data, the maximum specific growth rates in the presence of varying concentrations of each inhibitor ()j ) were determined. The results for each fermentation product are shown in Figures 1 - 3. There appears to be a threshold concentra-... 

Similar growth challenge experiments were performed using tert-butyl alcohol and n-hexanol. Although tert-butyl alcohol and n-hexanol are not products of this fermentation, the Up and Pq values obtained for these two alcohols were found to lie on the straight line shown in Figure 4, Linden et al. (3) have shown that the end product toxicity in the acetone-butanol fermentation occurs by altering membrane functionality. The linear relationship between and P ay indicate that the inhibition of each of these various compounds occurs by the same mechanism. 

From these studies of growth inhibition and fermentation kinetics in the acetone-butanol fermentation, the following conclusions may be made ... 

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