Date of Award


Document Type


Degree Name

Master of Science (MS)


Biological Sciences

Committee Chair

Carmen Scholz

Committee Member

Tatanya Sysoeva

Committee Member

Bernhard Vogler


Waste products as fuel., Butanol., Continuous culture (Microbiology), Bioreactors., Clostridium.


Crude glycerol is generated as a major waste product of the biodiesel industry. Purification of glycerol is difficult and costly due to toxic impurities. Clostridium pasteurianum is capable of converting crude glycerol into butanol, a useful fuel additive. To optimize conversion of glycerol to butanol, a continuous culture chemostat was used to improve cell growth and fermentation. The use of an extraction column containing a hollow fiber membrane was explored as a possible method of separating butanol from the culture. Deionized water and liposome vesicles were both tested as possible extraction solutions. Continuous culture was found to induce a steady state which consistently increased butanol yield by approximately 10% over that of batch cultures and decreased production of 1,3-PDO by at least 11% and minor fermentation products by at least 6.7%. Vesicles do not improve the efficiency of column extraction over deionized water. Three models are proposed for a bioreactor which combines the continuous culture with continuous liquid-based membrane extraction. The first two models use the extraction column to extract, one from the collection reservoir and one from the reactor itself. The third model uses a submerged semi-permeable membrane which separates the live culture and an extraction solution.



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