Date of Award

Summer 1986

Degree Type

Thesis - Restricted

Degree Name

Master of Science (MS)

Department

Biology

Abstract

All Zymomonas strains isolated so far contain plasmids. The significance of these plasmids is unknown but as Zymomonas strains are resistant to various antibiotics and heavy metals the plasmids may encode for these properties at least in some instances. The genus Zymomonas also has two other interesting aspects: (a) it is the only genus of gram-negative fermentative organisms which utilizes the Entner-Duodoroff pathway instead of the Embden-Meyerhoff pathway for fermentation, and (b) produces almost theoretical levels of ethanol per mole of glucose utilized. In spite of these interesting characteristics and a potential for commercial exploitation, the genetics of this genus has not been investigated. The reason for this is the lack of appropriate cloning vehicles and characterization of the native plasmids of Zymomonas. These studies report examination of a small 1.7 kb plasmid (pZM17) of Z. mobilis ATCC 10988 which has been cloned into a vector plasmid, pSUP202, to produce a chimeric plasmid molecule, pCT4. This hybrid plasmid contains two selectable antibiotic markers and is mobilizable in the presence of a conjugative plasmid. This hybrid molecule can be tested as a shuttle vector, functional in both Zymomonas and E. coli. Successful use as a shuttle vector will allow the elucidation of functions of Zymomonas plasmids, determination of chromosomal genes of this genus and ultimately in the cloning of foreign genes to increase the substrate range of Zymomonas.

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