ABE fermentation
Encyclopedia
Acetone-butanol-ethanol (ABE) fermentation is a process that uses bacterial fermentation to produce acetone
, n-butanol
, and ethanol
from starch
. It was the primary process used to make acetone
during World War II
, such as to produce cordite
. The process is anaerobic (done in the absence of oxygen), similar to how yeast
ferments sugars to produce ethanol
for wine, beer, or fuel. The process produces these solvents in a ratio of 3-6-1, or 3 parts acetone, 6 parts butanol and 1 part ethanol. It usually uses a strain of bacteria from the Clostridia
Class (Clostridium
Family). Clostridium acetobutylicum
is the most well-known strain, although Clostridium beijerinckii
has also been used for this process with good results.
The production of butanol
by biological means was first performed by Louis Pasteur
in 1861. In 1905, Schardinger found that acetone
could similarly be produced. Fernbach's work of 1911 involved the use of potato starch as a feedstock in the production of butanol. Industrial exploitation of ABE fermentation started in 1916 with Chaim Weizmann
's isolation of Clostridium acetobutylicum, as described in U.S. patent 1315585.
In order to make ABE fermentation profitable, many in-situ product recovery systems have been developed. These include gas stripping, pervaporation, membrane extraction, adsorption, and reverse osmosis
. However, at this time none of them have been implemented at an industrial scale.
For gas stripping, the most common gases used are the off-gases from the fermentation itself, a mix of carbon dioxide
and hydrogen
gas.
ABE fermentation, however, is not profitable when compared to the production of these solvents from petroleum. As such there are no currently operating ABE plants. During the 1950s and 1960s, ABE fermentation was replaced by petroleum chemical plants. Due to different raw materials costs, ABE Fermentation was viable in South Africa
until the early 1980s, with the last plant closing in 1983.
Acetone
Acetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...
, n-butanol
N-Butanol
n-Butanol or n-butyl alcohol or normal butanol is a primary alcohol with a 4-carbon structure and the molecular formula C4H9OH. Its isomers include isobutanol, 2-butanol, and tert-butanol...
, and ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
from starch
Starch
Starch or amylum is a carbohydrate consisting of a large number of glucose units joined together by glycosidic bonds. This polysaccharide is produced by all green plants as an energy store...
. It was the primary process used to make acetone
Acetone
Acetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...
during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, such as to produce cordite
Cordite
Cordite is a family of smokeless propellants developed and produced in the United Kingdom from 1889 to replace gunpowder as a military propellant. Like gunpowder, cordite is classified as a low explosive because of its slow burning rates and consequently low brisance...
. The process is anaerobic (done in the absence of oxygen), similar to how yeast
Yeast
Yeasts are eukaryotic micro-organisms classified in the kingdom Fungi, with 1,500 species currently described estimated to be only 1% of all fungal species. Most reproduce asexually by mitosis, and many do so by an asymmetric division process called budding...
ferments sugars to produce ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
for wine, beer, or fuel. The process produces these solvents in a ratio of 3-6-1, or 3 parts acetone, 6 parts butanol and 1 part ethanol. It usually uses a strain of bacteria from the Clostridia
Clostridia
The Clostridia are a class of Firmicutes, including Clostridium and other similar genera. They are distinguished from the Bacilli by lacking aerobic respiration. They are obligate anaerobes and oxygen is toxic to them. Species of the genus Clostridium are all Gram-positive and have the ability to...
Class (Clostridium
Clostridium
Clostridium is a genus of Gram-positive bacteria, belonging to the Firmicutes. They are obligate anaerobes capable of producing endospores. Individual cells are rod-shaped, which gives them their name, from the Greek kloster or spindle...
Family). Clostridium acetobutylicum
Clostridium acetobutylicum
Clostridium acetobutylicum, ATCC 824, is included in the genus Clostridium, is a commercially valuable bacterium sometimes called the "Weizmann Organism", after Jewish-Russian born Chaim Weizmann, then senior lecturer at the University of Manchester, England, used them in 1916 as a bio-chemical...
is the most well-known strain, although Clostridium beijerinckii
Clostridium beijerinckii
Clostridium beijerinckii is a gram positive, rod shaped, motile bacterium of the genus Clostridium. It has been isolated from feces and soil...
has also been used for this process with good results.
The production of butanol
Butanol
Butanol or butyl alcohol can refer to any of the four isomeric alcohols of formula C4H9OH:*n-Butanol, butan-1-ol, 1-butanol, n-butyl alcohol;*Isobutanol, 2-methylpropan-1-ol, isobutyl alcohol;...
by biological means was first performed by Louis Pasteur
Louis Pasteur
Louis Pasteur was a French chemist and microbiologist born in Dole. He is remembered for his remarkable breakthroughs in the causes and preventions of diseases. His discoveries reduced mortality from puerperal fever, and he created the first vaccine for rabies and anthrax. His experiments...
in 1861. In 1905, Schardinger found that acetone
Acetone
Acetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...
could similarly be produced. Fernbach's work of 1911 involved the use of potato starch as a feedstock in the production of butanol. Industrial exploitation of ABE fermentation started in 1916 with Chaim Weizmann
Chaim Weizmann
Chaim Azriel Weizmann, , was a Zionist leader, President of the Zionist Organization, and the first President of the State of Israel. He was elected on 1 February 1949, and served until his death in 1952....
's isolation of Clostridium acetobutylicum, as described in U.S. patent 1315585.
In order to make ABE fermentation profitable, many in-situ product recovery systems have been developed. These include gas stripping, pervaporation, membrane extraction, adsorption, and reverse osmosis
Reverse osmosis
Reverse osmosis is a membrane technical filtration method that removes many types of large molecules and ions from solutions by applying pressure to the solution when it is on one side of a selective membrane. The result is that the solute is retained on the pressurized side of the membrane and...
. However, at this time none of them have been implemented at an industrial scale.
For gas stripping, the most common gases used are the off-gases from the fermentation itself, a mix of carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
and hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
gas.
ABE fermentation, however, is not profitable when compared to the production of these solvents from petroleum. As such there are no currently operating ABE plants. During the 1950s and 1960s, ABE fermentation was replaced by petroleum chemical plants. Due to different raw materials costs, ABE Fermentation was viable in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
until the early 1980s, with the last plant closing in 1983.