Fermentations -
In
applied
microbiology,
the
term
fermentation
is
loosely
used
to
denote
any
process
in
which
microorganisms
are
involved
even
if
the
process
involves
strong
aeration
and
is
respiratory
in
nature
as
in
the
antibiotic
fermentations.
Energetically,
fermentations
are
poor
energy
yielding
processes
and
the
products
have
lower
energy
content
than
the
substrates.
In
terms
of
bond
energy,
fermentation
may
be
viewed
as
a
process
in
which
the
H
and
O
atoms
in
an
organic
molecule
are
regrouped
to
yield
a
carboxyl
group
or
CO2.
Fermentation
in
a
broad
sense,
can
be
defined
as
a
reaction
in
which
organic
compounds
serve
both
as
electron
donors
and
electron
acceptors.
Since
there
is
no
net
oxidation
in
a
fermentation,
the
number
of
moles
of
C,
H
and
0
remain
the
same
in
the
products
as
in
the
substrate,
as
it
occurs
in
the
conversion
of
glucose
to
lactic
acid
or
ethanol
F ermentation
differs
from
anaerobic
respiration
in
that
in
the
latter
oxygen
is
replaced
by
an
inorganic
electron
acceptor
such
as
NO3
or
SO4.
Two
typical
fermentations
that
have
been
studied
in
detail
art
(i)
the
ethanol
fermentation
in
yeast,
and
(ii)
the
lactic
acid
fermentation
in
the
lactic
bacteria