Analysis of dextrin dextranase from Gluconobacter oxydans
Date
2008-12
Authors
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Publisher
Stellenbosch : Stellenbosch University
Abstract
Dextran is a high value glucose polymer used in medicine and an array of laboratory
techniques. It is synthesised by lactic-acid bacteria from sucrose but has also reportedly
been produced by Gluconobacter oxydans (G. oxydans) from a range of
maltooligosaccharides (MOS) via the action of dextrin dextranase (DDase). In this
study the presence of DDase is investigated in two G. oxydans strains (ATCC 621H
and ATCC 19357) and shown to be present in the ATCC 19357 strain, but not in the
ATCC 621H strain. The enzyme was partially purified from the ATCC 19357 strain,
and its kinetic properties investigated. The partially purified protein was also digested
with trypsin, and de novo peptide sequences obtained from it. Several attempts were
made to obtain the gene coding for the DDase. These include amplifying an open
reading frame from the G. oxydans genome coding for a glycosyltransferase with the
approximate molecular weight of the DDase, using the peptide sequences obtained
from the partially purified protein to design degenerate PCR primers and the production
of a genomic DNA library for functional screening in E. coli. None of these approaches
led to the successful isolation of the extracellular DDase sequence.
Description
Thesis (MSc (Genetics. Institute for Plant Biotechnology (IPB)))--Stellenbosch University, 2008.
Keywords
Dextrin dextranase, Gluconobacter oxydans, Theses -- Plant biotechnology, Dissertations -- Plant biotechnology