Process

History

The technology being developed by Celtic Renewables Ltd's is an innovation of the ABE Fermentation Process. The process has been long established at industrial scale and the technology can be readily adapted for re-introduction in a modern biotechnology context.

During the former part of twentieth Century Acetone Butanol (AB) fermentation was a very important biotechnological process, surpassed only by ethanol fermentation, as the most successful industrial process. Its origins sprung from a high demand for natural rubber, where a shortage and expense had prompted research for a cheaper synthetic substitute.

 

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Demonstration of the mobility of solventogenic Clostridium 

This work was led by Chaim Weizmann whose work led to the isolation of a strain of Clostridium acetobutylicum, a strain which he referred to as BY. BY had the ability to produce acetone, butanol and ethanol as fermentation end-products. However, the work of Weizmann became invaluable for another reason. The onset of World War I demanded an abundance of munitions, smokeless gunpowder – cordite, was required in vast quantities.

Cordite manufacture required acetone and with the supply from Austria and Germany interrupted, left only a short supply from the US. Because of the capability of Weizmann’s BY strain to produce acetone, Weizmann made his work known and he was later commissioned to produce acetone using the ABE fermentation or Weizmann process, as it was also called.

Over the next twenty years expansion of AB fermentation continued on a global scale. In addition, improvements were made through the use of molasses, a cheap and plentiful substrate; and new strains, boosting the efficiency and solvent yield of the process. Demand for butanol continued and coupled with the requirement for acetone during World War II the AB industry was at its peak. In the Post–war years there was a very rapid decline in AB fermentation, which eventually led to all but a few plants closing.

The decline of the AB fermentation industry was due to the process being no longer economically viable and reasons for this were two-fold. Firstly, butanol could be synthesised by a more efficient and cheaper method, from crude oil. Secondly, competition had arose for the feedstock used at the time, molasses, which were being used in cattle feed. Leading to this once cheap and plentiful carbon source becoming too expensive for the AB industry to compete with the petrochemical industry.

Research and plant operation continued in very few places post Second World War. Plants in South Africa, China and Russia remained operational for decades afterwards. Eventually research was rekindled again in a wider field, including western societies, prompted by the oil crisis of the 1970s. This led to fuel alternatives being sought and in Brazil the Proalcool program begun, where ethanol produced from the fermentation of sugar cane, replaced the need for the importation of oil as a fuel.
The rare expertise in the ABE process at Celtic Renewables Ltd gives the company a strategic position and competitive advantage in the field of biobutanol development.

The rare expertise in the ABE process at Celtic Renewables Ltd gives the company a strategic position and competitive advantage in the field of biobutanol development.