Submitted to: Encyclopedia of Microbiology
Publication Type: Book / Chapter
Publication Acceptance Date: February 7, 2008
Publication Date: January 1, 2009
Citation: Qureshi, N. 2009. Solvent Production. In: Schaechter, M., editor. Encyclopedia of Microbiology. Oxford: Elsevier. p. 512-528. Technical Abstract: This article describes production of butanol [acetone-butanol-ethanol, (also called AB or ABE or solvent)] by fermentation using both traditional and current technologies. AB production from agricultural commodities such as corn and molasses was an important historical fermentation. Unfortunately, this fermentation ceased operation as it could not compete with butanol production from petrochemical processes. As a result of increased gasoline prices, production of AB is being revived after a gap of approximately 25 years in commercial activities. The old technology had numerous problems such as energy-inefficient recovery of AB by distillation, use of dilute sugar solutions, low reactor productivity, and low AB concentration in fermentation broth. During the last 25 years, significant progress has been made including development of better microbial strains, high productivity systems, simultaneous recovery of AB from bioreactors, use of concentrated sugar solutions, and production of butanol from agricultural residues. Simultaneous butanol fermentation and recovery using novel technologies have dramatically improved longevity of butanol production in batch and fed-batch reactors and solved numerous problems (including inhibition) associated with this fermentation. Additionally, use of novel substrates such as wheat straw has been explored in combination with simultaneous hydrolysis, fermentation, and product recovery.