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ASU Electronic Theses and Dissertations

This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.

In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.

Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at

The unicellular cyanobacterium Synechocystis sp. PCC 6803 contains a NiFe-type bidirectional hydrogenase that is capable of using reducing equivalents to reduce protons and generate H¬2. In order to achieve sustained H2 production using this cyanobacterium many challenges need to be overcome. Reported H2 production from Synechocystis is of low rate and often transient. Results described in this dissertation show that the hydrogenase activity in Synechocystis is quite different during periods of darkness and light. In darkness, the hydrogenase enzyme acts in a truly bidirectional way and a particular H2 concentration is reached that depends upon the amount of biomass involved …

Dutta, Ipsita, Vermaas, Willem FJ, Garcia-Pichel, Ferran, et al.
Created Date

Some cyanobacteria can generate hydrogen (H2) under certain physiological conditions and are considered potential agents for biohydrogen production. However, they also present low amounts of H2 production, a reaction reversal towards H2 consumption, and O2 sensitivity. Most attempts to improve H2 production have involved genetic or metabolic engineering approaches. I used a bio-prospecting approach instead to find novel strains that are naturally more apt for biohydrogen production. A set of 36, phylogenetically diverse strains isolated from terrestrial, freshwater and marine environments were probed for their potential to produce H2 from excess reductant. Two distinct patterns in H2 production were detected. …

Kothari, Ankita, Garcia-Pichel, Ferran, Vermaas, Willem F J, et al.
Created Date

Euendolithic cyanobacteria have the remarkable ability to actively excavate and grow within certain minerals. Their activity leads to increased erosion of marine and terrestrial carbonates, negatively affecting coral reef and bivalve ecology. Despite their environmental relevance, the boring mechanism has remained elusive and paradoxical, in that cyanobacteria alkalinize their surroundings, typically leading to carbonate precipitation, not dissolution. Thus, euendoliths must rely on unique adaptations to bore. Recent work using the filamentous model euendolith Mastigocoleus testarum strain BC008 indicated that excavation relied on transcellular calcium transport mediated by P-type ATPases, but the phenomenon remained unclear. Here I present evidence that excavation …

Guida, Brandon Scott, Garcia-Pichel, Ferran, Chandler, Douglas, et al.
Created Date