Expression Patterns of Genes and Enzymes Involved in Sugar Catabolism in Industrial Saccharomyces cerevisiae Strains Displaying Novel Fermentation Characteristics
F.
Jon
Meneses1,2
and
Vladimir
Jiranek1,3
1Department
of
Horticulture,
Viticulture
and
Oenology,
The
University
of
Adelaide,
PMB
1
Glen
Osmond,
SA
5064
2Coopers
Brewery
Ltd.,
461
South
Rd,
Regency
Park,
SA
5010
3Corresponding
author.
E-mail:
vladimir.jiranek@adelaide.edu.au
J. Inst. Brew. 108(3), 322-335, 2002 | VIEW ARTICLE
ABSTRACT
The
utilisation
of
maltose
or
sucrose
by
a
selection
of
nine
brewing,
baking
or
laboratory
strains
of
Saccharomyces
cerevisiae
was
either
repressible,
constitutive
or
absent.
Overall
fermentation
rate
showed
a
good
correlation
with
maximum
specific
maltose
transport
rate
(R2
=
0.79),
but
a
poor
correlation
with
maximum
maltase
activity
(R2
=
0.34),
implying
that
transport
rather
than
hydrolysis
of
maltose
was
a
rate-limiting
step
determining
fermentation
performance.
The
genetic
basis
for
differences
seen
between
the
strains
in
terms
of
fermentation
kinetics
was
investigated.
All
strains
were
found
to
possess
genomic
sequences
detectable
with
probes
for
the
MAL11
(AGT1),
MAL31
permease
genes
and
the
SUC2
invertase
gene,
however,
the
loci
present
and
the
pattern
of
expression
of
these
and
other
MAL
genes
varied
widely.
From
comparisons
of
sugar
utilisation
and
gene
expression
patterns,
constitutive
maltose
utilisation
in
strain
NCYC
1681
was
best
explained
by
AGT1
expression.
Such
expression
of
AGT1
was
not,
however,
mirrored
by
changes
in
the
pattern
of
expression
of
the
transcriptional
activator(s)
(MALx3).
Patterns
of
sucrose
utilisation
were
poorly
predicted
by
the
kinetics
of
SUC2
gene
expression,
indicating
that
other
SUC
loci
may
be
of
greater
importance.
Key words:
Fermentation,
gene
expression,
mutants,
Saccharomyces
cerevisiae,
sugar
uptake,
wort
sugars.
Publication no. G-2002-0827-061 ©2002 The Institute & Guild of Brewing