Hybrid thermochemical/biological processing of biomass for the production of polyhydroxyalkanoates and hydrogen gas from <i>Rhodospirillum rubrum</i> cultured on synthesis gas

dc.contributor.advisor Robert C. Brown
dc.contributor.author Chipman, David
dc.contributor.department Mechanical Engineering
dc.date 2018-08-12T03:58:05.000
dc.date.accessioned 2020-06-30T02:32:08Z
dc.date.available 2020-06-30T02:32:08Z
dc.date.copyright Thu Jan 01 00:00:00 UTC 2009
dc.date.embargo 2013-06-05
dc.date.issued 2009-01-01
dc.description.abstract <p>The goal of this research is to optimize PHA production in the syngas fermenting organism <i>Rhodospirillum rubrum</i>. Syngas fermentation is the hybrid thermochemical/ biological approach to processing biomass into valuable fuels and chemicals. The process begins with the gasification of biomass to produce syngas, a flammable gas mixture consisting primarily of carbon monoxide (CO), hydrogen (H<sub>2</sub>), and carbon dioxide (CO<sub>2</sub>). Microorganisms are then used to ferment the syngas into biofuels and chemicals.</p> <p><i>Rhodospirillum rubrum</i>, a non-sulfur purple bacterium, utilizes the CO in syngas to produce H<sub>2</sub> and polyhydroxyalkanoates (PHAs), biobased-biodegradable polymers. Information is limited pertaining to the optimization of growth media as well as the optimal harvest point for <i>R. rubrum</i> in terms of H<sub>2</sub> and PHA production.</p> <p>RRNCO growth media was optimized on the small scale (40 ml). The resulting media recipe was scaled up to 10L for the evaluation of the optimal harvest point. A syngas fermentation facility and control system was designed and developed for fermentation scale (10L) experiments. The results of the small scale experiments did not agree with literature in terms of the effect of the carbon to nitrogen balance on cellular PHA content. Yeast extract may have been acting as an additional source of available carbon and nitrogen in the media.</p> <p>The results of the harvest point optimization indicated that cell density and media acetate levels may serve as good indicators of maximum PHA production. PHA production appeared to maximize when cell growth reached late exponential phase or early stationary phase. Maximum PHA production corresponded well with the point of media acetate exhaustion.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/etd/10945/
dc.identifier.articleid 1968
dc.identifier.contextkey 2807166
dc.identifier.doi https://doi.org/10.31274/etd-180810-594
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath etd/10945
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/25151
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/etd/10945/Chipman_iastate_0097M_10786.pdf|||Fri Jan 14 18:31:29 UTC 2022
dc.subject.disciplines Mechanical Engineering
dc.subject.keywords hydrogen
dc.subject.keywords PHA
dc.subject.keywords polyhydroxyalkanoates
dc.subject.keywords Rhodospirillum rubrum
dc.subject.keywords syngas fermentation
dc.subject.keywords synthesis gas
dc.title Hybrid thermochemical/biological processing of biomass for the production of polyhydroxyalkanoates and hydrogen gas from <i>Rhodospirillum rubrum</i> cultured on synthesis gas
dc.type article
dc.type.genre thesis
dspace.entity.type Publication
relation.isOrgUnitOfPublication 6d38ab0f-8cc2-4ad3-90b1-67a60c5a6f59
thesis.degree.level thesis
thesis.degree.name Master of Science
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