ACS ES&T Engineering,
Journal Year:
2024,
Volume and Issue:
4(9), P. 2177 - 2185
Published: Aug. 5, 2024
This
study
tested
polyhydroxyalkanoate
(PHA)
production
by
usingPseudomonas
putida
KT2440
in
a
5
L
lab-scale
bioreactor,
employing
an
A
cell
dry
mass
concentration
of
8.69
±
0.45
g/L
was
achieved
with
volatile
fatty
acid
(VFA)
removal
efficiency
81.75
3.08%.
Remarkably,
this
the
highest
PHA
fraction
(34.81
1.67%).
Analysis
revealed
that
poly(3-hydroxybutyrate)
(PHB)
contributes
83.6
to
86.1%
total
followed
poly(3-hydroxyhexanoate)
(PHHx)
(6.6–8.6%)
and
poly(3-hydroxy-2-methylvalerate)
(PH2MV)
(4.9–8.3%).
Thermogravimetric
analysis
showed
polymer
started
degrading
at
temperature
150
°C
maximum
weight
loss
occurring
approximately
270
°C.
Differential
scanning
calorimetry
two
peaks
corresponding
melting
polymer:
140.6,
154.87
suggests
resulting
blend
different
copolymers.
outcome
is
poised
advance
development
unified
methods
within
circular
bioeconomy,
enhancing
both
economic
environmental
advantages.
International Journal of Polymer Science,
Journal Year:
2024,
Volume and Issue:
2024, P. 1 - 17
Published: Jan. 19, 2024
Polyhydroxyalkanoates
(PHAs)
are
biodegradable
and
biocompatible
polymers
that
produced
by
microorganisms
as
storage
materials
under
limited
nutrition
excess
carbon.
These
PHAs
have
been
found
to
be
ideal
for
replacing
synthetic
plastics
use
in
packaging
biomedical
applications.
In
this
study,
an
alkaliphilic
moderately
halophilic
bacterium
Halomonas
alkalicola
Ext
was
isolated
from
Lake
Simbi
Nyaima
western
Kenya
investigated
PHA
production.
Sudan
Black
B
Nile
Red
A
staining
showed
had
distinct
ability
accumulation
of
PHAs.
To
optimize
production,
the
grown
submerged
fermentation
varying
culture
conditions
different
sources
concentrations
carbon
nitrogen.
With
one-factor-at-a-time
(OFTA)
approach,
optimal
yields
were
obtained
after
72
hours
at
a
pH
10.0,
temperature
35°C,
2.5%
(w/v)
NaCl.
The
yielded
highest
biomass,
amounts
on
2%
galactose
0.1%
ammonium
sulfate
nitrogen,
respectively.
record
yield
0.071
g
g-1
with
titer
achieved
3.397
g/L
equivalent
41.8%
content.
Using
response
surface
methodology,
increased
1.5%
1.44
g/L,
while
content
improved
1.1-fold
45.57%.
Polymer
analysis
revealed
extracted
poly(3-hydroxybutyrate-co-3-hydroxyvalerate)
(PHBV)
(
id="M2">3−HB:3−HV=92:8
)
two
copolymer
subunits
3-hydroxyvaryrate
(3-HB)
3-hydroxybutyrate
(3-HV).
attained
efficient
conversion
into
PHBV
high
salinity
alkalinity
conditions.
Xylose
fermentation
often
faced
limitations
coupled
with
unbalanced
microbial
intracellular
metabolic
states.
Recent
development
in
cathodic
electro-fermentation
technologies
addresses
this
issue
by
balancing
states
and
influencing
the
intercellular
electron
load
of
various
microorganisms
a
cathode
electrode.
This
research
studied
feeding
strategies
mixed
culture
systems
aiming
at
long-term
enhancement
production
rates
or
yields
carboxylic
acids
e.g.,
propionate
butyrate,
using
xylose
as
raw
material.
The
results
compared
fed-batch
continuous
(poised
potential
-0.4
V
vs.
standard
hydrogen
electrode)
their
community
compositions.
highlighted
prompt
uninterrupted
cathode-assisted
metabolism
towards
butyrate
than
systems,
enhanced
product
yield
coefficients
(propionate
1.57-fold,
1.64-fold)
reactors
poised
to
open-circuit
controls.
16S
rRNA
gene
characterisation
revealed
different
operation
modes
that
influence
presence
bacterial
genera,
including
Clostridium
biofilm
planktonic
cells,
which
notably
played
crucial
role
processes.
