The nature of sorbital (a primary) and sorbose (a secondary) dehydrogenases of Gluconobacter species

The genus <i>Gluconobacter</i> is known to carry out limited oxidations using the NAD(P)-independent membrane-bound dehydrogenases in which the products are released back to the medium. Reports of further limited oxidations of these primary oxidation products by <i>Gluconobacter</i> in single step or sequential oxidations by secondary dehydrogenases are also published. The objective of this project was to evaluate the nature of one primary (sorbitol) dehydrogenase and one secondary (sorbose) dehydrogenase because of their importance in Vitamin C production. My hypotheses were that sorbitol (the primary) dehydrogenase is constitutive, while sorbose (the secondary) dehydrogenase is inducible. Six <i>Gluconobacter</i> strains from three different species grew on plates containing 50/0 sorbose, indicating their ability to oxidize sorbose thus possessing a secondary dehydrogenase. When four strains were tested for their ability to carry out the sequential oxidation of sorbitol and then sorbose on media containing growth-limiting sorbitol concentrations, three strains showed possible biphasic growth. However, thin layer chromatography of culture media did not support sequential sorbitol and sorbose oxidation. F erricyanide assays for sorbitol and sorbose dehydrogenases from membrane fractions isolated from cells grown on glycerol, sorbitol, or sorbose showed that sorbitol dehydrogenase activity in all four strains (three species) tested was always present (constitutive) and its specific activity was always enhanced by growth on sorbose. Membrane fractions showed no or very low constitutive sorbose dehydrogenase activity and no evidence that this secondary dehydrogenase was induced.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Biology

Department dc:contributor.department

Biology

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1996

Author dc:creator

• Anriany, Yuda Adha

Chair dc:contributor.committeechair

• Claus, George William

Committee members dc:contributor.committeemember

• Yousten, Allan A.
• Gregory, Eugene M.

• noninducible
• Gluconobacter
• sorbital dehydrogenase
• sorbase dehydrogenase
• biphasic growth
• constitutive

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-06082009-170814

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/42889