Engineering,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Jan. 1, 2024
n-caproate,
which
is
produced
via
chain
elongation
(CE)
using
waste
biomass,
can
supply
various
fossil-derived
products,
thus
advancing
the
realization
of
carbon
neutrality.
Ammonia
released
from
degradation
nitrogen-rich
biomass
act
as
a
nutrient
or
an
inhibitor
in
anaerobic
bioprocesses,
including
CE,
with
distinction
being
primarily
dependent
on
its
concentration.
Currently,
optimal
concentration
ammonia
and
threshold
toxicity
for
open-culture
n-caproate
production
ethanol
electron
donor,
along
underlying
mechanisms,
remain
unclear.
This
study
revealed
that
was
2
g∙L−1,
whereas
concentrations
exceeding
this
markedly
suppressed
CE
performance.
Exploration
mechanism
involvement
two
forms
(i.e.,
ammonium
ions
free
ammonia)
inhibitory
behavior.
High
levels
(5
g∙L−1)
induced
excessive
oxidation
reverse
β-oxidation
(RBO)
process,
directly
leading
to
enhanced
activities
enzymes
(phosphotransacetylase
acetate
kinase)
responsible
formation
diminished
butyryl-coenzyme
A
(CoA):
acetyl-CoA
transferase,
caproyl-CoA:
butyryl-CoA
transferase
are
involved
syntheses
n-butyrate
n-caproate.
Furthermore,
composition
microbial
community
shifted
Paraclostridium
dominance
(at
0.1
g∙L−1
co-dominance
Fermentimonas,
Clostridium
sensu
stricto
12,
15
at
ammonia.
However,
these
CE-functional
bacteria
were
mostly
absent
presence
ammonia).
Metagenomic
analysis
upregulation
functions
such
RBO,
fatty
acid
synthesis,
K+
efflux,
adenosine
triphosphatase
(ATPase)
metabolism,
metal
cation
export
ammonia,
collectively
contributing
production.
Conversely,
aforementioned
(excluding
export)
influx
by
undermining
both
detoxification
biosynthesis.
The
comprehensive
elucidation
ammonia-driven
mechanisms
influencing
production,
provided
study,
expected
inspire
researchers
devise
effective
strategies
alleviate
ammonia-induced
inhibition.
Fermentation,
Journal Year:
2022,
Volume and Issue:
8(7), P. 325 - 325
Published: July 11, 2022
Utilising
‘wastes’
as
‘resources’
is
key
to
a
circular
economy.
While
there
are
multiple
routes
waste
valorisation,
anaerobic
digestion
(AD)—a
biochemical
means
breakdown
organic
wastes
in
the
absence
of
oxygen—is
favoured
due
its
capacity
handle
variety
feedstocks.
Traditional
AD
focuses
on
production
biogas
and
fertiliser
products;
however,
such
low-value
products
combined
with
longer
residence
times
slow
kinetics
have
paved
way
explore
alternative
product
platforms.
The
intermediate
steps
conventional
AD—acidogenesis
acetogenesis—have
capability
produce
biohydrogen
volatile
fatty
acids
(VFA)
which
gaining
increased
attention
higher
energy
density
(than
biogas)
market
value,
respectively.
This
review
hence
focusses
specifically
VFAs
from
wastes.
With
revived
interest
these
products,
critical
analysis
recent
literature
needed
establish
current
status.
Therefore,
intensification
strategies
this
area
involving
three
main
streams:
substrate
pre-treatment,
parameters
recovery
discussed
detail
based
reported
last
decade.
techno-economic
aspects
future
pointers
clearly
highlighted
drive
research
forward
relevant
areas.
Biotechnology Advances,
Journal Year:
2024,
Volume and Issue:
73, P. 108363 - 108363
Published: April 22, 2024
In
recent
years,
there
has
been
growing
interest
in
harnessing
anaerobic
digestion
technology
for
resource
recovery
from
waste
streams.
This
approach
evolved
beyond
its
traditional
role
energy
generation
to
encompass
the
production
of
valuable
carboxylic
acids,
especially
volatile
fatty
acids
(VFAs)
like
acetic
acid,
propionic
and
butyric
acid.
VFAs
hold
great
potential
various
industries
biobased
applications
due
their
versatile
properties.
Despite
increasing
global
demand,
over
90%
are
currently
produced
synthetically
petrochemicals.
Realizing
large-scale
VFA
streams
offers
significant
eco-friendly
opportunities
but
comes
with
several
key
challenges.
These
include
low
yields,
unstable
acid
compositions,
complex
expensive
purification
methods,
post-processing
needs.
Among
these,
yield
composition
stand
out
as
most
critical
obstacles
impacting
economic
viability
competitiveness.
paper
seeks
offer
a
comprehensive
view
combining
complementary
modeling
approaches,
including
kinetic
microbial
modeling,
understand
workings
communities
metabolic
pathways
production,
enhance
efficiency,
regulate
profiles
through
integration
omics
bioreactor
data.
