On-line monitoring of microbial fermentation end-products synthesized by Clostridium thermocellum using Titrimetric Off-Gas Analysis (TOGA)

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dc.contributor.supervisor Cicek, Nazim (Biosystems Engineering) en_US
dc.contributor.author Blunt, Warren
dc.date.accessioned 2013-09-04T16:05:40Z
dc.date.available 2013-09-04T16:05:40Z
dc.date.issued 2013-09-04
dc.identifier.uri http://hdl.handle.net/1993/22133
dc.description.abstract Bioprocesses carried out for the production of fuels and other value-added co-products require effective process control strategies. The objective of this research is to apply Titrimetric Off-Gas Analysis (TOGA) for the on-line estimation of fermentation end products using Clostridium thermocellum. The hydrogen ion production, gaseous H2 and CO2, soluble H2 and CO2, as well as ethanol in the liquid phase and vapour phase, were monitored. All parameters, except the dissolved gases, showed good correlation with concurrent off-line analysis. The resulting mass and electron balances were close to theoretical values, and not significantly different from those determined using off-line analysis. Liquid-to-gas mass transfer limitations caused supersaturation of H2(aq) for a wide-range of operating conditions, and on average, ranged between 8-14 times the expected value at thermodynamic equilibrium. The supersaturation of CO2(aq) was conditional, and could be alleviated by increased sparging at agitation such that no significant mass transfer limitation was present. Simultaneous data on ethanol, CO2, and H2 could be obtained with the MIMS probe placed adjacent to the liquid surface in the reactor headspace. From this data, a metabolic model was proposed for the on-line estimation of formate and acetate using a mass balance and an electron balance. The model estimated formate concentrations with reasonable accuracy. Acetate predictions agreed with the qualitative trends, but the concentrations were inaccurate in comparison with off-line analysis. It was demonstrated that the sensor could provide on-line information on all major end-products synthesized by C. thermocellum. In conclusion, TOGA is a valuable instrument for the on-line monitoring and study of fermentation processes for cellulosic biofuels production en_US
dc.subject biofuels en_US
dc.subject on-line en_US
dc.subject monitoring en_US
dc.subject ethanol en_US
dc.subject hydrogen en_US
dc.subject biomass en_US
dc.title On-line monitoring of microbial fermentation end-products synthesized by Clostridium thermocellum using Titrimetric Off-Gas Analysis (TOGA) en_US
dc.degree.discipline Biosystems Engineering en_US
dc.contributor.examiningcommittee Levin, David (Biosystems Engineering) Sparling, Richard (Microbiology) Gapes, Daniel (Scion Research, Rotorua, New Zealand) en_US
dc.degree.level Master of Science (M.Sc.) en_US
dc.description.note October 2013 en_US

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