Characterization of plasmids among the three species of Gluconobacter

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Virginia Tech


The genus Gluconobacter consists of acetic acid bacteria which have the ability to generate acidic products from their substrates, particularly acetic acid from ethanol. For this reason, the gluconobacters live in acidic, sugary environments such as flowers, honey bees, fruits, cider, vinegar, wine and beer. The gluconobacters carry out a strictly respiratory type of metabolism using only oxygen as a terminal electron acceptor. They do not completely oxidize a substrate to carbon dioxide. Instead, they partially oxidize the substrate using membrane-bound dehydrogenases and excrete the product into the surrounding growth medium. It is these limited oxidations that make the gtuconobacters industrially useful.

Although much is known about the physiology of the limited oxidations in the gluconobacters, little is known of their genetics, particularly, their plasmids. The overall purpose of this dissertation was to determine if Gluconobacter plasmids correlate with oxidative capability and/or antibiotic resistance.

To achieve this goal, I first needed a way to screen strains of Gluconobacter for their ability to oxidize many different substrates. 'developed an assay that used an unusual artificial electron acceptor, tetranitroblue tetrazolium (TNBT) and then tested the ability of six strains to oxidize 13 chemical compounds. Although most strains were able to oxidize the 13 compounds tested, they accomplished this with varying extents of oxidation. These differences were noted even with strains representing the same species.



limited oxidations, antimicrobial susceptibility, hybridizations, phenotype