1.1 History of industrial biobutanol production

The initiation of the industrial acetone-butanol-ethanol (ABE) production by Clostridium fermentation is connected with the chemist Chaim Weizmann, working at the University of Manchester UK, who wished to make synthetic rubber containing butadiene or isoprene units from butanol or isoamyl alcohol and concentrated his effort on the isolation of microbial producers of butanol. Further, the development of acetone-butanol process was accelerated by World War I when acetone produced by ABE fermentation from corn in Dorset, UK was used for cordite production. However in 1916, the German blockade hampered the supply of grain and the production was transferred to Canada and later with the entry of the United States to the war, two distilleries in Terre Haute were adapted to

acetone production. After the war, the group of American businessmen bought Terre Haute plant and restored the production in 1920; at that time butanol was appreciated as solvent for automobile lacquers. Subsequently, with decreasing price of molasses new solventogenic strains were isolated and first plant using this feedstock was built at Bromborough in England near the port, in 1935. In 1936 the Weizmann patent expired and new acetone — butanol plants were erected in U. S.A., Japan, India, Australia and South Africa using usually molasses as the substrate. The Second World War again accelerated the process development and acetone became the most required product; the plant at Bromborough was expanded and semi continuous way of fermentation which cut the fermentation time to 30- 32h was accomplished here together with continuous distillation. At the end of the war, two thirds of butanol in U. S.A. was gained by fermentation but rise of petrochemical industry together with increasing price of molasses that started to be used for cattle feeding caused gradual decline of industrial acetone-butanol fermentation. Most of the plants in Western countries were closed by 1960 with the exception of Germiston factory in South Africa where cheap molasses and coal enabled to keep the process till 1983 (Jones & Woods, 1986). In addition to Western countries, the production of acetone and butanol was also supported in the Soviet Union. Here, in Dukshukino plant, in 1980s, the process was operated as semi continuous in multi-stage arrangement with possibility to combine both saccharidic and starchy substrates together with small portion (up to 10%) of lignocellulosic hydrolyzate and continuous distillation (Zverlov et al., 2006). In China, industrial fermentative acetone and butanol production began around 1960 and in 1980s there was the great expansion of the process. Originally, batch fermentation was changed to semi continuous 4-stage process in which the fermentation cycle was reduced to 20 h, the yield was about 35-37% from starch and the productivity was 2.3 times higher in comparison with batch process (Chiao & Sun, 2007). At the end of 20th century the most of Chinese plants were probably closed (Chiao & Sun, 2007) but now hundred thousands of tons of acetone and butanol per year are produced by fermentation in China (Ni & Sun, 2009).

Industrial production of ABE in the former Czechoslovakia started with a slight delay comparing with other already mentioned countries. Bacterial cultures were isolated, selected and tested for many years by professor J. Dyr, head of the Department of Fermentation Technology of the Institute of Chemical Technology in Prague who lead a small research team and preparatory works for the plant design (Dyr & Protiva, 1958). Acetone — butanol plant was fully in operation from 1952 till 1965. The main raw materials were firstly potatoes which were later changed for rye. Various bacteria cultures (all were classified as Clostridium acetobutylicum) were prepared for several main crops (potatoes, rye, molasses) which increased flexibility of the production. Annual production of solvents increased from year to year but did not exceed 1000 tons. Concentration of total solvents in the broth varied around 17-18 g. LA Process itself was run as batch, pH was never controlled, propagation ratio in large fermentation section was 1 : 35. The whole fermentation time was on average 36-38 h. Critical point for each fermentation was "break" in acidity after which started a strong evolution of gases and solvents. In case of potatoes and rye there were no nutrients supplied to the fermentation broth. The only process necessary for the pre-treatment of the raw materials of starch origin was their steaming under pressure in Henze cooker. Initial concentration of starch ranges from 4.5 to 5% wt. In spite of keeping all sanitary precaution (similarly today’s GMP) two types of unexpected failures occurred. Firstly it was contamination by bacteriophage (not possible to analyze it in those times) which appeared approx. three times during the lifetime and always was followed by a total sanitation and complete change of the producing strain. Secondly there appeared another unexpected event, i. e. a final turn to a complete acidification without initiation of solvent production indicated by a spore creation. This situation appeared in the range from 1 to 4% of the total number of batches.