Date of Award

8-2013

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Biosystems Engineering

Advisor

Drapcho, Caye M

Committee Member

Nghiem , Nhuan P

Committee Member

Tharayil , Nishanth

Abstract

Biological production of succinic acid from a cull peach based medium was studied using Escherichia coli AFP 184 in a dual-phase batch process including an aerobic growth phase and an anaerobic production phase. Experiments were performed to study the effects of corn steep liquor supplement and exogenous hydrogen supply. About one half of the sucrose in the medium was converted to fermentable sugars glucose and fructose during sterilization. The remaining sucrose was hydrolyzed with invertase. The viscosity of the medium was reduced from 350 cP to 50 cP to allow efficient oxygen transfer by a commercial enzyme product. In the medium without corn steep liquor supplement, fructose consumption was incomplete and the final succinic acid concentration of 38. 8 g/L was achieved at a yield of 0.77 g/g sugars consumed and a succinate:acetate molar ratio of 5.1:1. When corn steep liquor was supplemented to the medium the final succinic acid concentration increased to 47.0 g/L and the yield to 0.87 g/g sugars consumed but the succinate:acetate molar ratio remained at 5.6:1. With hydrogen sparging into the unsupplemented medium the final succinic acid concentration increased to 45.5 g/L and the yield to 0.84 g/g sugars consumed. In addition, the succinate:acetate molar ratio increased to 7.7:1. The potential use of cull peach as feedstock for succinic acid production and the possibility of its integration with other biological processes such as butanol and hydrogen productions in a biorefinery are discussed.

Included in

Engineering Commons

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