Date of Award

8-2009

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Biosystems Engineering

Advisor

Drapcho, Caye M.

Committee Member

Walker , Terry H.

Committee Member

Henson , Michael J.

Abstract

ABSTRACT
Thermotoga neapolitana is a marine hyperthermophilic bacterium that ferments various sugars to hydrogen and acetate. In this study, cull peaches were used as carbon source in a defined medium for biohydrogen production and produced 18 % to 25% hydrogen in the headspace. The hydrogen production varied from 6.4-7.7 mmol H2/g peach (dry weight). The hydrogen concentration did not increase after 20 hours of incubation. The final pH decreased to 4.9 after 20 hours. Unautoclaved peach medium can be used for hydrogen production. The hydrogen production did not increase with the increase in peach concentration from 50 g/L to 100 g/L (wet weight). Yeast extract, as nitrogen source, was found important for hydrogen production. Soybean meal was found to be a good nitrogen source with cull peaches as carbon source for biohydrogen production.
The pH had profound effect on biohydrogen production by Thermotoga neapolitana. The optimum initial pH for hydrogen production using peach medium as was 8.0. The mass of hydrogen produced increased when pH was adjusted after 12 hours of incubation. The hydrogen production increased from 7.07 mmol H2/g peach (dry weight) to 8.73 mmol H2/g peach (dry weight), when pH was adjusted. The incubation time also increased from 20 hours to 40 hours for complete fermentation on pH adjusted medium. The amount of soluble COD utilized increases from 3.81 to 4.95 g COD/L, when pH was adjusted. The number of moles of carbon dioxide produced was same as that of hydrogen. The maximum rate of production of hydrogen observed in this study was 3.31 mmol H2/L.h. The hydrogen production was same when pH was adjusted to two different pH of 6.5 and 7.5 respectively after 12 hours. The amount of hydrogen produced decreased when substrate concentration was increased from 50 g/L to 100 g/L (wet weight0 and pH was adjusted after 12 hours of incubation.

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