Statistical Optimisation of Medium Constituent Variables for Biogas Production from N-acetylglucosamine by Clostridium beijerinckii and Clostridium paraputrificum
Abstract
Statistically
based
experimental
designs
were
applied
to
optimise
medium
constituent
for
biogas
production
utilizing
N-‐acetylglucosamine
as
a
carbon
source
for
Clostridium
beijerinckii
and
Clostridium
paraputrificum.
The
important
medium
constituents
influencing
total
biogas
produced,
identified
by
the
Plackett
and
Burman
method,
were
FeSO4.7H2O
and
initial
pH
for
C.
beijerinckii
cultures
whilst
for
C.
paraputrificum
cultures
N-‐acetylglucosamine,
L-‐
cysteine.HCl.H2O
and
MgCl2.
A
one
factor
L-‐cysteine.HCl.H2O
optimization
design
was
applied
to
investigate
the
ideal
concentration
of
L-‐cysteine.HCl.H2O
required
to
achieve
an
anaerobic
environment
for
optimum
C.
beijerinckii
total
biogas
production.
The
Method
of
Steepest
Ascent
was
then
employed
to
locate
the
optimal
area
of
the
significant
medium
variables.
Using
the
Box-‐behnken
method,
experimental
results
showed
that
there
were
significant
linear
effects
of
independent
variables,
N-‐acetylglucosamine
for
C.
beijerinckii
cultures
and
for
C.
paraputrificum
cultures
N-‐acetylglucosamine,
L-‐cysteine.HCl.H2O
and
MgCl2
on
total
biogas
volume.
Significant
curvature
or
quadratic
effects
of
N-‐
acetylglucosamine
and
L-‐cysteine.HCl.H2O
were
identified
for
C.
paraputrificum
cultures.
There
were
no
significant
interaction
effects
between
medium
constituent
variables
on
resulting
biogas
volume.
The
optimal
conditions
for
the
maximum
volume
of
biogas
produced
for
C.
beijerinckii
cultures
were
21
g/l
of
N-‐
acetylglucosamine,
0.1
g/l
of
FeSO4.7H2O
and
initial
pH
of
6.11
and
for
C.
paraputrificum
were
29
g/l
of
N-‐acetylglucosamine,
0.27
g/l
of
L-‐
cysteine.HCl.H2O
and
0.4
g/l
of
MgCl2.
Using
this
statistical
optimization
strategy,
the
total
biogas
volume
from
N-‐acetylglucosamine
utilization
increased
from
150
ml/l
to
6533
ml
/l
in
the
C.
beijerinckii
cultures
and
100
ml/l
to
5350
ml/l
in
the
C.
paraputificum
cultures.
The
maximum
yield
of
bio-‐hydrogen
by
C.
paraputrificum
from
N-‐acetylglucosamine
was
2.55
mol
of
H2
/
mol
of
N-‐
acetylglucosamine
and
by
C.
beijerinckii
was
2.43
mol
of
H2
/
mol
of
N-‐
acetylglucosamine.
Publication date
2014-05-21Published version
https://doi.org/10.18745/th.13660https://doi.org/10.18745/th.13660